Beryllium copper BeCu
Cu with 1.80 to 2.00 wt% Be, 0.20 wt% minimum Ni plus Co, and 0.6 wt% maximum Ni plus Co plus Fe
Also known as UNS C17200, EN 2.1247, EN name CW101C, SAE J461, JIS H3270, CDA 172 · 6 more
Beryllium copper C17200 (CuBe2, Alloy 25) is a copper alloy with 1.80 to 2.00 wt% beryllium that is sold age-hardened for strength.
Evidence level
2 of 5
Lab-measured
- 0Predicted only. No one has made it, or no measurement exists.
- 1Calculated. Only calculated or predicted values from sources.
- 2Lab-measured. Measured properties with their conditions stated.
- 3Space-relevant tests. Measured in conditions relevant to space, such as vacuum or atomic oxygen.
- 4Ground-qualified. Qualified for an application on the ground.
- 5Flown or field-proven. Flight or field results exist.
Strength when aged
1000 to 1380 MPa yield
Conductivity
25 to 30 %IACS
Stiffness
131 GPa
Weight
8.36 g/cm3
Non-magnetic
< 1.0006
Recipe, share of the weight
- Be not statedBeryllium
- Ni+Co not statedNickel plus cobalt
- Cu not statedCopper
Best for
High strength with useful conductivity and non-magnetic behaviour in springs, bushings, bearings and connectors, once beryllium exposure is controlled
Weakest at
Health: beryllium dust, mist and fume are a serious inhalation hazard. Strength also depends on temper, since annealed stock yields at only 130 to 250 MPa
Risk at a glance
- People Moderate. Serious inhalation hazard
- If it fails Moderate. Low strength in the annealed temper
- Corrosion Low. Wikipedia says C17200 has effective corrosion-resistant properties in harsh conditions such as seawater and down-hole environments.
Quick facts: BeCu
| Property | Value | Basis |
|---|---|---|
| Density | 8.36 g/cm³ | 1 sourced value |
| Yield strength | 130 to 1,380 MPa | 4 sourced values across conditions |
| Tensile strength | 410 to 1,550 MPa | 4 sourced values across conditions |
| Young's modulus | 131 GPa | 1 sourced value |
| Thermal conductivity | 105 W/(m·K) | 1 sourced value |
| Thermal expansion (CTE) | 17.5 ppm/K | 1 sourced value |
| Melting point | 870 °C | 1 sourced value |
| Electrical resistivity | 5.8e-8 to 6.9e-8 Ω·m | 1 sourced value |
What is the density of Beryllium copper (BeCu)?
Beryllium copper (BeCu) has a density of 8.36 g/cm³. The source and test conditions are listed in the properties table on this page.
What is the thermal conductivity of Beryllium copper (BeCu)?
Beryllium copper (BeCu) has a thermal conductivity of 105 W/(m·K). The source and test conditions are listed in the properties table on this page.
What is the coefficient of thermal expansion of Beryllium copper (BeCu)?
Beryllium copper (BeCu) has a coefficient of thermal expansion of 17.5 ppm/K. The source and test conditions are listed in the properties table on this page.
What is the melting point of Beryllium copper (BeCu)?
Beryllium copper (BeCu) has a melting point of 870 °C. The source and test conditions are listed in the properties table on this page.
What is the yield strength of Beryllium copper (BeCu)?
Beryllium copper (BeCu) has a yield strength of 130 to 1,380 MPa. The range covers 4 sourced values across the tempers, forms and test conditions the sources report; room-temperature values are used where a source states a temperature.
What are the other names and codes for Beryllium copper (BeCu)?
Beryllium copper (BeCu) is also written as UNS C17200, EN 2.1247, EN name CW101C, SAE J461, JIS H3270, CDA 172. Each code is printed in the source listed beside it in the designations table.
What is Beryllium copper (BeCu) used for?
Uses recorded in the sources include Bushings, bearings and springs; Circular and coaxial connectors, test probes and compression contacts.
Why it exists
Beryllium copper is used where a copper alloy must be strong and springy. Materion gives it as the highest-strength copper alloy, with conductivity considerably higher than other high-strength copper alloys, and it is non-magnetic and non-sparking. Its strength comes from age-hardening with 1.80 to 2.00 wt% beryllium, so the same alloy can be soft and easy to form in one temper and very strong in another. The price of that strength is beryllium, whose dust and fume are a serious health hazard.
Where it's used
Bearings and bushings
Materion lists bushings and bearings for aircraft among the typical applications of its tube, and Wikipedia lists springs and load cells as uses where the alloy must keep its shape under repeated stress.
Connectors and contacts
Materion lists circular and coaxial connectors, test probes and compression contacts among typical rod and bar applications.
Recipe
Cu with 1.80 to 2.00 wt% Be, 0.20 wt% minimum Ni plus Co, and 0.6 wt% maximum Ni plus Co plus Fe; UNS C17200 (CuBe2, Alloy 25)
C17200 is a copper alloy (Cu) with 1.80 to 2.00 wt% beryllium, plus small amounts of nickel and cobalt. It is sold in a solution-annealed (A) condition and age-hardened to its high-strength tempers at 600 to 675 °F (315 to 357 °C) (Materion).
| Ingredient | Share of the weight | What it does |
|---|---|---|
| Beryllium Be | not stated | The age-hardening element. Materion calls the alloy precipitation age-hardened, which gives the high-strength tempers. |
| Nickel plus cobalt Ni+Co | not stated | Minor additions. Materion sets a maximum of 0.6 wt% for nickel, cobalt and iron together. |
| Copper Cu | not stated | The matrix and the main metal. |
Weight shares are as printed in the sources.
What it can do
Strength when aged
1000 to 1380 MPa yield
measured
In the AT and HT tempers, the 0.2% offset yield strength is 1000 to 1210 MPa (AT) and 1100 to 1380 MPa (HT) for thin sections, according to Materion.
Conductivity
25 to 30 %IACS
measured
Materion gives 25 to 30 %IACS for the age-hardened condition, against 5.8 to 6.9 µΩ-cm resistivity.
Stiffness
131 GPa
measured
The modulus of elasticity is 131 GPa (19,000 ksi) in the age-hardened condition.
Weight
8.36 g/cm3
measured
Density is 8.36 g/cm3 after heat treatment and 8.30 g/cm3 before it, per Materion's footnote.
Non-magnetic
< 1.0006
measured
The tube datasheet gives a relative magnetic permeability below 1.0006.
How it compares
Materion describes C17200 as having the highest strength of any copper alloy, with electrical and thermal conductivity considerably greater than other high-strength copper alloys. The USGS says copper alloys with nickel and silicon, tin, titanium or phosphor bronze may replace beryllium-copper, but with reduced performance. Read the rows below as values for this alloy only.
The same measurements for each material, so you can compare them. Each row names the key condition under the value; the full conditions and methods are in the numbered notes under Technical details. Other materials are shown beside it; each was measured under its own conditions, so open its page before comparing closely. Compare every grade in the family.
| Measurement | BeCu | Cu | C360 | C954 | C630 | C510 | C260 | Cu-Ag | CuCrZr | CuNi 70/30 | C21000 | CW614N | C75200 | C521 | C655 | Cu-Te | Sn/Cu |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Thermal behavior and safety | |||||||||||||||||
| Melting point (solidus), C17200Value printed in a Materion datasheet | 870 °C2 | 1083 °C | 954 °C | 1027 °C | 1060 °C | 954 to 1049 °C | 916 °C | no data | 1081 °C | 1170 to 1240 °C | 954 °C | 875 to 890 °C | 1060 to 1110 °C | 882 to 1027 °C | 971 to 1027 °C | 1080 °C | 231.9 °C |
| Thermal conductivity at 25 °C, C17200 age-hardenedValue printed in a Materion datasheet | 105 W/(m·K)6 | 391 W/(m·K) | 116 W/(m·K) | 58.7 W/(m·K) | 63 W/(m·K) | 84 W/(m·K) | 121.2 W/(m·K) | no data | 323 W/(m·K) | 29 W/(m·K) | 234 W/(m·K) | 123 W/(m·K) | 32 W/(m·K) | 67 W/(m·K) | 36.3 W/(m.K) | 355 W/(m·K) | 66.6 W/(m·K) |
| Physical and electrical | |||||||||||||||||
| Density, C17200 age-hardened | 8.36 g/cm³1 | 8.9 g/cm³ | 8.5 g/cm³ | 7.45 g/cm³ | 7.58 g/cm³ | 8.86 g/cm³ | 8.53 g/cm³ | no data | 8.94 g/cm³ | 8.94 g/cm³ | 8.86 g/cm³ | 8.46 g/cm³ | 8.7 g/cm³ | 8.79 g/cm³ | 8.53 g/cm³ | 8.94 g/cm³ | 7.28 g/cm³ |
| Electrical conductivity, C17200 age-hardenedRange printed in a Materion datasheet | 25 to 30 %IACS4 | 58 MS/m | 26 %IACS | 13 %IACS | 7 %IACS | 15 %IACS | 28 %IACS | > 58 MS/m | > 46.4 MS/m | no data | 56 %IACS | 25 %IACS | 6 %IACS | 13 %IACS | 7 %IACS | 93 %IACS | 58 MS/m |
| Electrical resistivity, C17200 age-hardenedRange printed in a Materion datasheet | 5.8 to 6.9 μΩ-cm5 | no data | 6.63 µΩ·cm | 13.33 µΩ·cm | 0.172 µΩ·m | 8.7×10^-6 ohm·cm | 6.15 µΩ·cm | no data | no data | 37.4 µΩ·cm | 3.08 µΩ·cm | no data | no data | no data | 24.6 microohm-cm | no data | 11.5 µΩ·cm |
| Other measurements | |||||||||||||||||
| Modulus of elasticity, C17200 age-hardenedValue printed in a Materion datasheet | 131 GPa3 | 117 GPa | no data | 1.07×10^5 MPa | 117 GPa | 110 GPa | 1.1×10^5 MPa | no data | 117 GPa | no data | 117 GPa | 97 GPa | 135 GPa | 115 GPa | 1.03×10^5 MPa | 1.17×10^5 MPa | 50 GPa |
| Coefficient of thermal expansion, C17200 | 17.5 ppm/K7 | 17.6 ppm/K | 20.5 ppm/K | 16.2 ppm/K | 15 ppm/K | 17.8 µm/(m·°C) | 20 ppm/K | no data | 17.1 ppm/K | 13.2 to 16.2 ppm/K | 18 ppm/K | 21.4 ppm/K | 17.7 ppm/K | 17.4 µm/(m·°C) | 18 um/(m.°C) | 16.5 ppm/K | 22 ppm/K |
| Relative magnetic permeability, C17200 age-hardenedUpper limit printed in a Materion tube datasheet | < 1.001 -8 | no data | no data | no data | no data | no data | no data | no data | no data | no data | no data | no data | no data | no data | no data | no data | no data |
| Yield strength 0.2% offset, annealed temper A (TB00) | 130 to 250 MPa9 | 69 MPa | > 130 MPa | > 221 MPa | > 295 MPa | 550 MPa | 103 MPa | no data | > 450 MPa | 124 to 179 MPa | no data | > 220 MPa | no data | > 350 MPa | 310 MPa | > 205 MPa | no data |
| Yield strength 0.2% offset, hard temper H (TD04) | 520 to 720 MPa10 | 69 MPa | > 130 MPa | > 221 MPa | > 295 MPa | 550 MPa | 103 MPa | no data | > 450 MPa | 124 to 179 MPa | no data | > 220 MPa | no data | > 350 MPa | 310 MPa | > 205 MPa | no data |
| Yield strength 0.2% offset, age-hardened temper AT (TF00) | 1000 to 1210 MPa11 | 69 MPa | > 130 MPa | > 221 MPa | > 295 MPa | 550 MPa | 103 MPa | no data | > 450 MPa | 124 to 179 MPa | no data | > 220 MPa | no data | > 350 MPa | 310 MPa | > 205 MPa | no data |
| Yield strength 0.2% offset, age-hardened temper HT (TH04) | 1100 to 1380 MPa12 | 69 MPa | > 130 MPa | > 221 MPa | > 295 MPa | 550 MPa | 103 MPa | no data | > 450 MPa | 124 to 179 MPa | no data | > 220 MPa | no data | > 350 MPa | 310 MPa | > 205 MPa | no data |
| Tensile strength, annealed temper A (TB00) | 410 to 590 MPa13 | 179 to 262 MPa | > 330 MPa | > 586 MPa | > 585 MPa | > 485 MPa | 324 MPa | 180 N/mm2 | 480 to 560 MPa | 358 to 414 MPa | 235 MPa | > 360 MPa | 370 to 430 MPa | 475 to 580 MPa | 538 MPa | > 260 MPa | no data |
| Tensile strength, hard temper H (TD04) | 620 to 900 MPa14 | 179 to 262 MPa | > 330 MPa | > 586 MPa | > 585 MPa | > 485 MPa | 324 MPa | 180 N/mm2 | 480 to 560 MPa | 358 to 414 MPa | 235 MPa | > 360 MPa | 370 to 430 MPa | 475 to 580 MPa | 538 MPa | > 260 MPa | no data |
| Tensile strength, age-hardened temper AT (TF00) | 1140 to 1380 MPa15 | 179 to 262 MPa | > 330 MPa | > 586 MPa | > 585 MPa | > 485 MPa | 324 MPa | 180 N/mm2 | 480 to 560 MPa | 358 to 414 MPa | 235 MPa | > 360 MPa | 370 to 430 MPa | 475 to 580 MPa | 538 MPa | > 260 MPa | no data |
| Tensile strength, age-hardened temper HT (TH04) | 1280 to 1550 MPa16 | 179 to 262 MPa | > 330 MPa | > 586 MPa | > 585 MPa | > 485 MPa | 324 MPa | 180 N/mm2 | 480 to 560 MPa | 358 to 414 MPa | 235 MPa | > 360 MPa | 370 to 430 MPa | 475 to 580 MPa | 538 MPa | > 260 MPa | no data |
| Elongation, annealed temper A (TB00) | 20 to 75 %17 | 35 % | > 15 % | > 12 % | > 10 % | > 13 % | 62 % | > 37 % | > 10 % | 30 to 45 % | 45 % | > 20 % | 40 % | > 25 % | 17 % | > 8 % | no data |
| Elongation, hard temper H (TD04) | 8 to 30 %18 | 35 % | > 15 % | > 12 % | > 10 % | > 13 % | 62 % | > 37 % | > 10 % | 30 to 45 % | 45 % | > 20 % | 40 % | > 25 % | 17 % | > 8 % | no data |
| Elongation, age-hardened temper AT (TF00) | 4 to 10 %19 | 35 % | > 15 % | > 12 % | > 10 % | > 13 % | 62 % | > 37 % | > 10 % | 30 to 45 % | 45 % | > 20 % | 40 % | > 25 % | 17 % | > 8 % | no data |
| Elongation, age-hardened temper HT (TH04) | 2 to 9 %20 | 35 % | > 15 % | > 12 % | > 10 % | > 13 % | 62 % | > 37 % | > 10 % | 30 to 45 % | 45 % | > 20 % | 40 % | > 25 % | 17 % | > 8 % | no data |
Why choose it, and why not
Good for
- Springs, bushings and bearings that need high strength and a non-magnetic, non-sparking alloy
- Connectors, contacts and test probes that need strength together with conductivity
- Recycling: the USGS says scrap may supply as much as 20% to 25% of beryllium consumption
Watch out for
- Beryllium dust, mist and fume: inhalation can cause chronic beryllium disease, and IARC lists beryllium as a Category 1 carcinogen
- Temper matters: annealed stock is soft, and the high strengths need the printed ageing step
- Supply is concentrated: the United States, Brazil, China and Nigeria produced about 99% of 2025 mine output in the USGS table (shares computed from the table, with rounded world total)
- No space-environment test data were found for this alloy
Beryllium copper C17200 is a strong, conductive, non-magnetic copper alloy whose age-hardened tempers reach 1000 to 1380 MPa yield strength and 25 to 30 %IACS conductivity. Its beryllium content makes dust and fume a serious health hazard, and its strength depends on the temper chosen. This profile has no space-environment data.
Technical details
For scientists and researchers. Everything above comes from the record below: every number with its method, its conditions and its source.
Other names and standards
The same grade under other systems, as datasheets and standards print them. Each code was checked against the page it comes from.
| System | Codes |
|---|---|
| UNS | C17200 |
| EN | 2.1247 |
| EN name | CW101C |
| SAE | J461 |
| JIS | H3270 |
| CDA | 172 |
| ASTM | B196 (rod and bar), B643 (tube) |
| AMS | 4533 (rod and bar), 4535 (tube) |
| Trade name | CuBe2, Alloy 25 |
Notes
The method, full conditions and any caveat for the numbered rows above.
| # | Measurement | Method | Conditions | Caveat |
|---|---|---|---|---|
| 1 | Density, C17200 age-hardened | Value printed in a Materion datasheet for the age-hardened condition | grade C17200 (Alloy 25)temper precipitation age-hardened (heat treated)unit in source 0.302 lb/in3before heat treatment 8.30 g/cm3 (0.300 lb/in3), as a note in the same table | — |
| 2 | Melting point (solidus), C17200 | — | grade C17200 (Alloy 25)unit in source 1600 °Fproperty type solidus | — |
| 3 | Modulus of elasticity, C17200 age-hardened | — | grade C17200 (Alloy 25)temper precipitation age-hardened (heat treated)unit in source 19,000 ksi | — |
| 4 | Electrical conductivity, C17200 age-hardened | — | grade C17200 (Alloy 25)temper precipitation age-hardened (heat treated)unit in source 25 - 30% IACS | — |
| 5 | Electrical resistivity, C17200 age-hardened | — | grade C17200 (Alloy 25)temper precipitation age-hardened (heat treated)unit in source 5.8 - 6.9 μΩ - cm | — |
| 6 | Thermal conductivity at 25 °C, C17200 age-hardened | — | grade C17200 (Alloy 25)temper precipitation age-hardened (heat treated)temperature 25 °Cunit in source 60 BTU/ft hr °F | — |
| 7 | Coefficient of thermal expansion, C17200 | Value printed in a Materion datasheet, metric line | grade C17200 (Alloy 25)temperature not stated in the tableunit in source 17.5 x 10-6 m/m °C | — |
| 8 | Relative magnetic permeability, C17200 age-hardened | — | grade C17200 (Alloy 25)temper precipitation age-hardened (heat treated)unit in source < 1.0006 | — |
| 9 | Yield strength 0.2% offset, annealed temper A (TB00) | Range printed in a Materion datasheet, mechanical properties table | grade C17200 (Alloy 25)temper A (TB00), solution annealedsize 0.030 to 14 in (0.76 to 356 mm) diameter or thicknessunit in source 20 - 35 ksi | — |
| 10 | Yield strength 0.2% offset, hard temper H (TD04) | Range printed in a Materion datasheet, mechanical properties table | grade C17200 (Alloy 25)temper H (TD04), hardsize 0.030 to 0.375 in (0.76 to 9.5 mm) diameter or thicknessunit in source 75 - 105 ksi | — |
| 11 | Yield strength 0.2% offset, age-hardened temper AT (TF00) | Range printed in a Materion datasheet, mechanical properties table | grade C17200 (Alloy 25)temper AT (TF00), precipitation age-hardenedsize 0.030 to 3 in (0.76 to 76 mm) diameter or thicknessheat treatment 600 to 675 °F (315 to 357 °C), after 3 hoursunit in source 145 - 175 ksi | — |
| 12 | Yield strength 0.2% offset, age-hardened temper HT (TH04) | Range printed in a Materion datasheet, mechanical properties table | grade C17200 (Alloy 25)temper HT (TH04), precipitation age-hardenedsize 0.030 to 0.375 in (0.76 to 9.5 mm) diameter or thicknessheat treatment 600 to 675 °F (315 to 357 °C), after 2 to 3 hoursunit in source 160 - 200 ksi | — |
| 13 | Tensile strength, annealed temper A (TB00) | Range printed in a Materion datasheet, mechanical properties table | grade C17200 (Alloy 25)temper A (TB00), solution annealedsize 0.030 to 14 in (0.76 to 356 mm) diameter or thicknessunit in source 60 - 85 ksi | — |
| 14 | Tensile strength, hard temper H (TD04) | Range printed in a Materion datasheet, mechanical properties table | grade C17200 (Alloy 25)temper H (TD04), hardsize 0.030 to 0.375 in (0.76 to 9.5 mm) diameter or thicknessunit in source 90 - 130 ksi | — |
| 15 | Tensile strength, age-hardened temper AT (TF00) | Range printed in a Materion datasheet, mechanical properties table | grade C17200 (Alloy 25)temper AT (TF00), precipitation age-hardenedsize 0.030 to 3 in (0.76 to 76 mm) diameter or thicknessheat treatment 600 to 675 °F (315 to 357 °C), after 3 hoursunit in source 165 - 200 ksi | — |
| 16 | Tensile strength, age-hardened temper HT (TH04) | Range printed in a Materion datasheet, mechanical properties table | grade C17200 (Alloy 25)temper HT (TH04), precipitation age-hardenedsize 0.030 to 0.375 in (0.76 to 9.5 mm) diameter or thicknessheat treatment 600 to 675 °F (315 to 357 °C), after 2 to 3 hoursunit in source 185 - 225 ksi | — |
| 17 | Elongation, annealed temper A (TB00) | Range printed in a Materion datasheet, mechanical properties table (percent column) | grade C17200 (Alloy 25)temper A (TB00), solution annealedsize 0.030 to 14 in (0.76 to 356 mm) diameter or thickness | — |
| 18 | Elongation, hard temper H (TD04) | Range printed in a Materion datasheet, mechanical properties table (percent column) | grade C17200 (Alloy 25)temper H (TD04), hardsize 0.030 to 0.375 in (0.76 to 9.5 mm) diameter or thickness | — |
| 19 | Elongation, age-hardened temper AT (TF00) | Range printed in a Materion datasheet, mechanical properties table (percent column) | grade C17200 (Alloy 25)temper AT (TF00), precipitation age-hardenedsize 0.030 to 3 in (0.76 to 76 mm) diameter or thicknessheat treatment 600 to 675 °F (315 to 357 °C), after 3 hours | — |
| 20 | Elongation, age-hardened temper HT (TH04) | Range printed in a Materion datasheet, mechanical properties table (percent column) | grade C17200 (Alloy 25)temper HT (TH04), precipitation age-hardenedsize 0.030 to 0.375 in (0.76 to 9.5 mm) diameter or thicknessheat treatment 600 to 675 °F (315 to 357 °C), after 2 to 3 hours | — |
Corrosion and compatibility
What happens when it meets other materials and environments.
| Environment | Concern | What happens |
|---|---|---|
| Seawater and down-hole oil and gas environments | low | Wikipedia says C17200 has effective corrosion-resistant properties in harsh conditions such as seawater and down-hole environments.1 |
| General service | low | Materion and voestalpine both list corrosion resistance among the alloy's properties, with no rate or test condition.2 |
| # | Environment | Details | Test conditions |
|---|---|---|---|
| 1 | Seawater and down-hole oil and gas environments | The same page says the alloy withstands sulphide and chloride stress corrosion cracking and resists the effects of carbon dioxide and hydrogen embrittlement. No corrosion rate, test duration or specimen was read in any source. | basis Qualitative statements in a web encyclopaedia; no test data read |
| 2 | General service | Materion names high fatigue strength and resistance to wear, corrosion, galling and stress relaxation. voestalpine says the alloy has excellent conductivity and corrosion resistance and is suited to connectors and harsh-environment components. | basis Manufacturer and supplier statements; no test data read |
Risks and side effects
Hazards to people, what happens when a cell overheats, and how the material is handled and stored.
For people
The alloy itself is a solid copper alloy, but processing it can release beryllium dust or fume, and that is the serious hazard.
- Lungs
- Inhaled beryllium can cause chronic beryllium disease, which restricts the exchange of oxygen between the lungs and the bloodstream. Materion says processing beryllium-containing alloys poses a health risk without safe practice.
- Limits
- US law sets an 8-hour average limit of 0.2 µg/m3 and a 15-minute limit of 2.0 µg/m3, with an action level of 0.1 µg/m3.
- Carcinogen
- IARC lists beryllium and its compounds as Category 1 carcinogens, according to Wikipedia.
If it fails
These failure routes come from the datasheets and are about temper and heat treatment, not corrosion failure.
- Soft stock
- Annealed rod and bar yields at 130 to 250 MPa, against 1000 to 1380 MPa for the aged AT and HT tempers.
- Wrong ageing
- Materion gives its values only for the precipitation age-hardened condition, so a part aged outside the printed window is outside the quoted properties.
Handling and storage
- Follow the sheet
- Read the Safety Data Sheet and Materion's beryllium safety guidance before working with the material.
- Specify the temper
- Properties vary with diameter or thickness, so state the temper and size on every order.
Test details
The original wording and numbers from the sources, for readers who want them.
Failure risks
| Failure | Trigger and consequence |
|---|---|
| Low strength in the annealed tempermoderate severity | Using A (TB00) stock where a high-strength part is needed without an age-hardening stepAnnealed rod and bar has a 0.2% offset yield strength of 130 to 250 MPa, against 1000 to 1380 MPa for the aged AT and HT tempers (thin sections). |
| Properties outside the stated ageing windowmoderate severity | Age-hardening outside 600 to 675 °F (315 to 357 °C) or for a time other than the printed oneMaterion gives its properties for the precipitation age-hardened condition only, so a part aged outside the printed window is outside the quoted values. The datasheet gives no measured consequence of that deviation. |
Side effects on surrounding parts
| Affects | Effect |
|---|---|
| Choice of substitute alloy in a design | The USGS says copper alloys with nickel and silicon, tin, titanium or other alloying elements, and phosphor bronze, may replace beryllium-copper, but the substitution can result in substantially reduced performance. |
Handling and storage
- Read and follow the Safety Data Sheet and Materion's beryllium safety guidance before working with this material.
- Specify the temper and size. Materion says properties may vary by diameter (rod) or thickness (bar) and specifies the physical and mechanical values only for the precipitation age-hardened condition.
Supply and geography
How common the raw materials are and where they come from.
Beryllium (mine production)
- Top producers (2025)
- United States 53.5%, Brazil 18.6%, China 17.9%, Nigeria 9.3%
- Recycling
- USGS: recovered beryllium from new and old scrap may account for as much as 20% to 25% of total beryllium consumption. The leading US producer recovered about 40% of the beryllium content of new and old beryllium alloy scrap under its programme.
- Substitutes
- USGS: copper alloys with nickel and silicon, tin, titanium or other alloying elements, and phosphor bronze, may be substituted for beryllium-copper alloys, with reduced performance.
Documents
Datasheets, safety data sheets, papers and standards you can open.
Full record
The complete spore, as stored. Free to reuse under CC-BY-4.0. Images keep the licence shown with each one.
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spore: profile
id: beryllium-copper
spore_version: 0.2
family: copper-alloys
name: Beryllium copper
abbreviation: BeCu
role: high-strength, non-magnetic conductive spring alloy
category: metals
type: copper-alloys
summary: |
Beryllium copper C17200 (CuBe2, Alloy 25) is a copper alloy with 1.80 to 2.00 wt% beryllium that is sold age-hardened for strength. Materion gives a 0.2% offset yield strength of 1000 to 1210 MPa in the AT temper and 1100 to 1380 MPa in the HT temper for thin sections, an electrical conductivity of 25 to 30 %IACS and a density of 8.36 g/cm3. The alloy is non-magnetic and non-sparking. Its main hazard is beryllium dust and fume: inhalation can cause chronic beryllium disease, and the legal exposure limits are very low.
best_for: High strength with useful conductivity and non-magnetic behaviour in springs, bushings, bearings and connectors, once beryllium exposure is controlled
weakest_at: 'Health: beryllium dust, mist and fume are a serious inhalation hazard. Strength also depends on temper, since annealed stock yields at only 130 to 250 MPa'
identity:
formula: Cu with 1.80 to 2.00 wt% Be, 0.20 wt% minimum Ni plus Co, and 0.6 wt% maximum Ni plus Co plus Fe; UNS C17200 (CuBe2, Alloy 25)
source: materion-rodbar
where: Chemical composition table, row C17200 (Beryllium 1.80 to 2.00, Nickel plus Cobalt 0.20 min, Nickel plus Cobalt plus Iron 0.6 max, Copper balance). The same composition is printed in the Aircraft Materials AMS 4533 sheet (Be 1.8-2.0, Co 0.2 min).
designations:
- system: UNS
code: C17200
source: materion-rodbar
where: Industry standards and specifications line, first entry C17200; title line Alloy 25 (C17200) Rod and Bar
- system: EN name
code: CW101C
source: harald-cube2
where: 'Designations line: EN CW101C, CW101C'
- system: EN
code: '2.1247'
source: harald-cube2
where: 'Designations line: W.Nr. 2.1247'
- system: Trade name
code: CuBe2
source: harald-cube2
where: 'Designations line: CuBe2'
- system: Trade name
code: Alloy 25
source: materion-rodbar
where: 'Title line: Alloy 25 (C17200) Rod and Bar'
- system: CDA
code: '172'
source: aircraft-ams4533
where: 'Page title: Beryllium Copper Alloy 25 (UNS C17200 / CDA 172); composition table column CDA 172'
- system: ASTM
code: B196
note: rod and bar
source: materion-rodbar
where: 'Industry standards and specifications line: ASTM B-196'
- system: ASTM
code: B643
note: tube
source: materion-tube
where: 'Industry standards and specifications line: ASTM B643'
- system: AMS
code: '4533'
note: rod and bar
source: materion-rodbar
where: 'Industry standards and specifications line: AMS 4533'
- system: AMS
code: '4535'
note: tube
source: materion-tube
where: 'Industry standards and specifications line: AMS 4535'
- system: SAE
code: J461
source: materion-rodbar
where: 'Industry standards and specifications line: SAE J 461'
- system: JIS
code: H3270
source: materion-rodbar
where: 'Industry standards and specifications line: JIS H3270'
tags:
environments: []
applications:
- mechanisms
- electronics-and-chips
properties:
- benchmark: density
label: Density, C17200 age-hardened
value: 8.36
unit: g/cm3
scope: material
conditions:
grade: C17200 (Alloy 25)
temper: precipitation age-hardened (heat treated)
unit_in_source: 0.302 lb/in3
before_heat_treatment: 8.30 g/cm3 (0.300 lb/in3), as a note in the same table
method: Value printed in a Materion datasheet for the age-hardened condition
status: ground
source: materion-rodbar
where: Physical properties table, column Density, footnote **
- benchmark: melting_point
label: Melting point (solidus), C17200
value: 870
unit: °C
scope: material
conditions:
grade: C17200 (Alloy 25)
unit_in_source: 1600 °F
property_type: solidus
method: Value printed in a Materion datasheet
status: ground
source: materion-rodbar
where: Physical properties table, column Melting Point (Solidus)
- benchmark: elastic_modulus
label: Modulus of elasticity, C17200 age-hardened
value: 131
unit: GPa
scope: material
conditions:
grade: C17200 (Alloy 25)
temper: precipitation age-hardened (heat treated)
unit_in_source: 19,000 ksi
method: Value printed in a Materion datasheet
status: ground
source: materion-rodbar
where: Physical properties table, column Elastic Modulus
- benchmark: electrical_conductivity
label: Electrical conductivity, C17200 age-hardened
value: 25
value_high: 30
bound: range
unit: '%IACS'
scope: material
conditions:
grade: C17200 (Alloy 25)
temper: precipitation age-hardened (heat treated)
unit_in_source: 25 - 30% IACS
method: Range printed in a Materion datasheet
status: ground
source: materion-rodbar
where: Physical properties table, column Electrical Conductivity/Resistivity, first line
- benchmark: electrical_resistivity
label: Electrical resistivity, C17200 age-hardened
value: 5.8
value_high: 6.9
bound: range
unit: μΩ-cm
scope: material
conditions:
grade: C17200 (Alloy 25)
temper: precipitation age-hardened (heat treated)
unit_in_source: 5.8 - 6.9 μΩ - cm
method: Range printed in a Materion datasheet
status: ground
source: materion-rodbar
where: Physical properties table, column Electrical Conductivity/Resistivity, second line
- benchmark: thermal_conductivity
label: Thermal conductivity at 25 °C, C17200 age-hardened
value: 105
unit: W/(m·K)
scope: material
conditions:
grade: C17200 (Alloy 25)
temper: precipitation age-hardened (heat treated)
temperature: 25 °C
unit_in_source: 60 BTU/ft hr °F
method: Value printed in a Materion datasheet
status: ground
source: materion-rodbar
where: Physical properties table, column Thermal Conductivity (25 °C), metric line
- benchmark: cte
label: Coefficient of thermal expansion, C17200
value: 17.5
unit: ppm/K
scope: material
conditions:
grade: C17200 (Alloy 25)
temperature: not stated in the table
unit_in_source: 17.5 x 10-6 m/m °C
method: Value printed in a Materion datasheet, metric line
status: ground
source: materion-rodbar
where: Physical properties table, column Thermal Expansion Coefficient, metric line
- benchmark: relative_magnetic_permeability
label: Relative magnetic permeability, C17200 age-hardened
value: 1.0006
bound: upper
unit: '-'
scope: material
conditions:
grade: C17200 (Alloy 25)
temper: precipitation age-hardened (heat treated)
unit_in_source: < 1.0006
method: Upper limit printed in a Materion tube datasheet
status: ground
source: materion-tube
where: Physical properties table, column Relative Magnetic Permeability
- benchmark: yield_strength
label: Yield strength 0.2% offset, annealed temper A (TB00)
value: 130
value_high: 250
bound: range
unit: MPa
scope: material
conditions:
grade: C17200 (Alloy 25)
temper: A (TB00), solution annealed
size: 0.030 to 14 in (0.76 to 356 mm) diameter or thickness
unit_in_source: 20 - 35 ksi
method: Range printed in a Materion datasheet, mechanical properties table
status: ground
source: materion-rodbar
where: Mechanical properties table, row A (TB00), column 0.2% Offset Yield Strength, MPa
- benchmark: yield_strength
label: Yield strength 0.2% offset, hard temper H (TD04)
value: 520
value_high: 720
bound: range
unit: MPa
scope: material
conditions:
grade: C17200 (Alloy 25)
temper: H (TD04), hard
size: 0.030 to 0.375 in (0.76 to 9.5 mm) diameter or thickness
unit_in_source: 75 - 105 ksi
method: Range printed in a Materion datasheet, mechanical properties table
status: ground
source: materion-rodbar
where: Mechanical properties table, row H (TD04) 0.030 - 0.375, column 0.2% Offset Yield Strength, MPa
- benchmark: yield_strength
label: Yield strength 0.2% offset, age-hardened temper AT (TF00)
value: 1000
value_high: 1210
bound: range
unit: MPa
scope: material
conditions:
grade: C17200 (Alloy 25)
temper: AT (TF00), precipitation age-hardened
size: 0.030 to 3 in (0.76 to 76 mm) diameter or thickness
heat_treatment: 600 to 675 °F (315 to 357 °C), after 3 hours
unit_in_source: 145 - 175 ksi
method: Range printed in a Materion datasheet, mechanical properties table
status: ground
source: materion-rodbar
where: Mechanical properties table, row AT (TF00) 0.030 - 3, column 0.2% Offset Yield Strength, MPa
- benchmark: yield_strength
label: Yield strength 0.2% offset, age-hardened temper HT (TH04)
value: 1100
value_high: 1380
bound: range
unit: MPa
scope: material
conditions:
grade: C17200 (Alloy 25)
temper: HT (TH04), precipitation age-hardened
size: 0.030 to 0.375 in (0.76 to 9.5 mm) diameter or thickness
heat_treatment: 600 to 675 °F (315 to 357 °C), after 2 to 3 hours
unit_in_source: 160 - 200 ksi
method: Range printed in a Materion datasheet, mechanical properties table
status: ground
source: materion-rodbar
where: Mechanical properties table, row HT (TH04) 0.030 - 0.375, column 0.2% Offset Yield Strength, MPa
- benchmark: ultimate_tensile_strength
label: Tensile strength, annealed temper A (TB00)
value: 410
value_high: 590
bound: range
unit: MPa
scope: material
conditions:
grade: C17200 (Alloy 25)
temper: A (TB00), solution annealed
size: 0.030 to 14 in (0.76 to 356 mm) diameter or thickness
unit_in_source: 60 - 85 ksi
method: Range printed in a Materion datasheet, mechanical properties table
status: ground
source: materion-rodbar
where: Mechanical properties table, row A (TB00), column Ultimate Tensile Strength, MPa
- benchmark: ultimate_tensile_strength
label: Tensile strength, hard temper H (TD04)
value: 620
value_high: 900
bound: range
unit: MPa
scope: material
conditions:
grade: C17200 (Alloy 25)
temper: H (TD04), hard
size: 0.030 to 0.375 in (0.76 to 9.5 mm) diameter or thickness
unit_in_source: 90 - 130 ksi
method: Range printed in a Materion datasheet, mechanical properties table
status: ground
source: materion-rodbar
where: Mechanical properties table, row H (TD04) 0.030 - 0.375, column Ultimate Tensile Strength, MPa
- benchmark: ultimate_tensile_strength
label: Tensile strength, age-hardened temper AT (TF00)
value: 1140
value_high: 1380
bound: range
unit: MPa
scope: material
conditions:
grade: C17200 (Alloy 25)
temper: AT (TF00), precipitation age-hardened
size: 0.030 to 3 in (0.76 to 76 mm) diameter or thickness
heat_treatment: 600 to 675 °F (315 to 357 °C), after 3 hours
unit_in_source: 165 - 200 ksi
method: Range printed in a Materion datasheet, mechanical properties table
status: ground
source: materion-rodbar
where: Mechanical properties table, row AT (TF00) 0.030 - 3, column Ultimate Tensile Strength, MPa
- benchmark: ultimate_tensile_strength
label: Tensile strength, age-hardened temper HT (TH04)
value: 1280
value_high: 1550
bound: range
unit: MPa
scope: material
conditions:
grade: C17200 (Alloy 25)
temper: HT (TH04), precipitation age-hardened
size: 0.030 to 0.375 in (0.76 to 9.5 mm) diameter or thickness
heat_treatment: 600 to 675 °F (315 to 357 °C), after 2 to 3 hours
unit_in_source: 185 - 225 ksi
method: Range printed in a Materion datasheet, mechanical properties table
status: ground
source: materion-rodbar
where: Mechanical properties table, row HT (TH04) 0.030 - 0.375, column Ultimate Tensile Strength, MPa
- benchmark: elongation
label: Elongation, annealed temper A (TB00)
value: 20
value_high: 75
bound: range
unit: '%'
scope: material
conditions:
grade: C17200 (Alloy 25)
temper: A (TB00), solution annealed
size: 0.030 to 14 in (0.76 to 356 mm) diameter or thickness
method: Range printed in a Materion datasheet, mechanical properties table (percent column)
status: ground
source: materion-rodbar
where: Mechanical properties table, row A (TB00), column Elongation, Percent
- benchmark: elongation
label: Elongation, hard temper H (TD04)
value: 8
value_high: 30
bound: range
unit: '%'
scope: material
conditions:
grade: C17200 (Alloy 25)
temper: H (TD04), hard
size: 0.030 to 0.375 in (0.76 to 9.5 mm) diameter or thickness
method: Range printed in a Materion datasheet, mechanical properties table (percent column)
status: ground
source: materion-rodbar
where: Mechanical properties table, row H (TD04) 0.030 - 0.375, column Elongation, Percent
- benchmark: elongation
label: Elongation, age-hardened temper AT (TF00)
value: 4
value_high: 10
bound: range
unit: '%'
scope: material
conditions:
grade: C17200 (Alloy 25)
temper: AT (TF00), precipitation age-hardened
size: 0.030 to 3 in (0.76 to 76 mm) diameter or thickness
heat_treatment: 600 to 675 °F (315 to 357 °C), after 3 hours
method: Range printed in a Materion datasheet, mechanical properties table (percent column)
status: ground
source: materion-rodbar
where: Mechanical properties table, row AT (TF00) 0.030 - 3, column Elongation, Percent
- benchmark: elongation
label: Elongation, age-hardened temper HT (TH04)
value: 2
value_high: 9
bound: range
unit: '%'
scope: material
conditions:
grade: C17200 (Alloy 25)
temper: HT (TH04), precipitation age-hardened
size: 0.030 to 0.375 in (0.76 to 9.5 mm) diameter or thickness
heat_treatment: 600 to 675 °F (315 to 357 °C), after 2 to 3 hours
method: Range printed in a Materion datasheet, mechanical properties table (percent column)
status: ground
source: materion-rodbar
where: Mechanical properties table, row HT (TH04) 0.030 - 0.375, column Elongation, Percent
corrosion:
- environment: Seawater and down-hole oil and gas environments
headline: Wikipedia says C17200 has effective corrosion-resistant properties in harsh conditions such as seawater and down-hole environments.
effect: The same page says the alloy withstands sulphide and chloride stress corrosion cracking and resists the effects of carbon dioxide and hydrogen embrittlement. No corrosion rate, test duration or specimen was read in any source.
rating: low
conditions:
basis: Qualitative statements in a web encyclopaedia; no test data read
source: wikipedia-becu
where: Corrosion resistance paragraph
- environment: General service
headline: Materion and voestalpine both list corrosion resistance among the alloy's properties, with no rate or test condition.
effect: Materion names high fatigue strength and resistance to wear, corrosion, galling and stress relaxation. voestalpine says the alloy has excellent conductivity and corrosion resistance and is suited to connectors and harsh-environment components.
rating: low
conditions:
basis: Manufacturer and supplier statements; no test data read
source: materion-rodbar
where: Overview paragraph (first paragraph of the rod and bar datasheet)
risks:
hazards:
- text: Beryllium dust, mist and fume are the main hazard. Inhalation can cause chronic beryllium disease, which restricts the exchange of oxygen between the lungs and the bloodstream.
ghs: []
source: wikipedia-beryllium
where: Toxicity, Inhalation section
- text: Materion warns that processing beryllium-containing alloys poses a health risk if safe practices are not followed, and that inhalation of airborne beryllium can cause serious lung diseases in some individuals.
ghs: []
source: materion-rodbar
where: Health and Safety section
- text: 'US occupational limits for airborne beryllium: an 8-hour time-weighted average of 0.2 µg/m3, a 15-minute short-term limit of 2.0 µg/m3, and an action level of 0.1 µg/m3 as an 8-hour TWA.'
ghs: []
source: cornell-1910-1024
where: 29 CFR 1910.1024, paragraph (c)(1) time-weighted average PEL, paragraph (c)(2) short-term exposure limit, and paragraph (b) definition of action level
- text: The GHS box for elemental beryllium lists signal word Danger and hazard statements H301, H315, H317, H319, H330, H335, H350i and H372. These describe the element, not this alloy; the alloy's own safety data sheet was not read.
ghs:
- H301
- H315
- H317
- H319
- H330
- H335
- H350i
- H372
source: wikipedia-beryllium
where: GHS labelling box in the infobox, Hazards
- text: Wikipedia says IARC lists beryllium and its compounds as Category 1 carcinogens, and that the NTP also lists beryllium as a carcinogen.
ghs: []
source: wikipedia-beryllium
where: Toxicity, Inhalation section (IARC statement)
failure_risks:
- mode: Low strength in the annealed temper
trigger: Using A (TB00) stock where a high-strength part is needed without an age-hardening step
consequence: Annealed rod and bar has a 0.2% offset yield strength of 130 to 250 MPa, against 1000 to 1380 MPa for the aged AT and HT tempers (thin sections).
severity: moderate
source: materion-rodbar
where: Mechanical properties table, rows A (TB00), AT (TF00) and HT (TH04)
- mode: Properties outside the stated ageing window
trigger: Age-hardening outside 600 to 675 °F (315 to 357 °C) or for a time other than the printed one
consequence: Materion gives its properties for the precipitation age-hardened condition only, so a part aged outside the printed window is outside the quoted values. The datasheet gives no measured consequence of that deviation.
severity: moderate
source: materion-rodbar
where: Physical properties footnote (*) and Heat Treatment Required column of the mechanical properties table
side_effects:
- text: The USGS says copper alloys with nickel and silicon, tin, titanium or other alloying elements, and phosphor bronze, may replace beryllium-copper, but the substitution can result in substantially reduced performance.
affects: Choice of substitute alloy in a design
source: usgs-mcs2026-beryllium
where: Substitutes paragraph
handling:
- text: Read and follow the Safety Data Sheet and Materion's beryllium safety guidance before working with this material.
source: materion-rodbar
where: Health and Safety section
- text: Specify the temper and size. Materion says properties may vary by diameter (rod) or thickness (bar) and specifies the physical and mechanical values only for the precipitation age-hardened condition.
source: materion-rodbar
where: Physical properties footnote (*), and mechanical properties footnote (*)
mitigations: []
uses:
- application: mechanisms
device: Bushings, bearings and springs
example: Materion lists bushings and bearings for aircraft among the typical applications of its tube. Wikipedia lists springs, spring wire and load cells as uses where the alloy must keep its shape under repeated stress.
source: materion-tube
where: Typical applications paragraph (tube datasheet); Uses section of wikipedia-becu
- application: electronics-and-chips
device: Circular and coaxial connectors, test probes and compression contacts
example: Materion lists these as typical applications of its rod and bar, citing high fatigue strength and resistance to wear and stress relaxation. voestalpine says the alloy is non-magnetic and non-sparking and suited to connectors.
source: materion-rodbar
where: Overview paragraph; voestalpine C17200 page (voestalpine-c17200)
supply:
- subject: Beryllium (mine production)
producers:
- country: United States
share_percent: 53.5
year: 2025
- country: Brazil
share_percent: 18.6
year: 2025
- country: China
share_percent: 17.9
year: 2025
- country: Nigeria
share_percent: 9.3
year: 2025
critical_lists: []
recycling: 'USGS: recovered beryllium from new and old scrap may account for as much as 20% to 25% of total beryllium consumption. The leading US producer recovered about 40% of the beryllium content of new and old beryllium alloy scrap under its programme.'
substitutes:
- 'USGS: copper alloys with nickel and silicon, tin, titanium or other alloying elements, and phosphor bronze, may be substituted for beryllium-copper alloys, with reduced performance.'
source: usgs-mcs2026-beryllium
where: World Mine Production and Reserves table, 2025e world total (rounded) 430 t of beryllium content; shares calculated by Space Mushroom from the country values 230, 80, 77 and 40 over that total. Import sources 2021 to 24 (Kazakhstan 31%, Latvia 25%, Japan 19%, Germany 5%, other 20%) in Domestic Production and Use. Recycling and Substitutes sections.
documents:
- title: Materion Alloy 25 (C17200) Rod and Bar Data Sheet, DS-AM-23 (2020), hosted by voestalpine
type: datasheet
url: https://voestalpine.com/specialtymetals/nam/app/uploads/sites/255/2024/07/Alloy-25-C17200-Rod-and-Bar-Data-Sheet.pdf
year: 2020
- title: Materion Alloy 25 (C17200) Tube Data Sheet, hosted by voestalpine
type: datasheet
url: https://voestalpine.com/specialtymetals/nam/app/uploads/sites/255/2024/07/Alloy-25-C17200-Tube-Data-Sheet.pdf
- title: 'USGS Mineral Commodity Summaries 2026: Beryllium'
type: report
url: https://pubs.usgs.gov/periodicals/mcs2026/mcs2026-beryllium.pdf
year: 2026
- title: Aircraft Materials, Beryllium Copper Alloy 25 (UNS C17200 / CDA 172) technical data sheet, AMS 4533
type: datasheet
url: https://aircraftmaterials.com/data/copper/ams4533.html
- title: 29 CFR 1910.1024 Beryllium, Cornell Legal Information Institute
type: standard
url: https://www.law.cornell.edu/cfr/text/29/1910.1024
- title: Beryllium copper, Wikipedia
type: report
url: https://en.wikipedia.org/wiki/Beryllium_copper
- title: Beryllium, Wikipedia (toxicity and GHS box)
type: report
url: https://en.wikipedia.org/wiki/Beryllium
- title: Harald Pihl, Copper Alloy 25 / CuBe2 (CW101C) product page
type: report
url: https://www.haraldpihl.com/en/products/copper-alloys/cube2-cw101c/
- title: voestalpine Specialty Metals, C17200 BeCu / Alloy 25 product page
type: report
url: https://www.voestalpine.com/specialtymetals/nam/en/materials/c17200-becu-alloy-25/
gaps:
- Outgassing, atomic-oxygen, radiation and thermal-vacuum test results for beryllium copper were not found in any source opened in this run; the profile has no space-environment data.
- The alloy's own safety data sheet was not read. The hazard entries use OSHA's regulation text, Wikipedia's toxicity section and the GHS box for elemental beryllium, which describes the element and not C17200.
- NIOSH IDLH and REL values for beryllium were not entered. The CDC page returned HTTP 403, and the only other copy found was an unofficial 1994 archive, so it was not used.
- 'PubChem records were not used: the site returned a bot-check page.'
- The USGS 2026 beryllium summary does not state a critical minerals list, so critical_lists is empty.
- 'Hardness values are not entered: the datasheets read in this run do not print a hardness, and the Wikipedia Rockwell figures are not from a datasheet.'
- Electrical conductivity and thermal conductivity are given for the age-hardened condition only; values for the annealed temper were not printed in the datasheets read.
- Fatigue strength, stress-relaxation, galling and cold-welding figures were not found as numbers; Materion names these properties without values.
- Cryogenic behaviour and radiation effects were not looked up.
- Wikipedia gives a solidus of 866 °C in its own text. The Materion value of 870 °C from the datasheet is used instead, and the Wikipedia value is not entered.
- relative_magnetic_permeability is a snake_case name that is not in the canonical property list, so the canonical unit conversion may not apply.
- The voestalpine page states NACE MR0175 and ISO 15156 sour-service listings for C17200. These were not checked against the standards and are not entered.
- Density of the annealed (before heat treatment) condition is kept in the conditions field as printed; no separate property row was added.
sources:
materion-rodbar:
title: Materion Alloy 25 (C17200) Rod and Bar Data Sheet, DS-AM-23 (2020)
id: Materion Performance Alloys and Composites, DS-AM-23, copyright 2020
url: https://voestalpine.com/specialtymetals/nam/app/uploads/sites/255/2024/07/Alloy-25-C17200-Rod-and-Bar-Data-Sheet.pdf
year: 2020
kind: datasheet
license: Manufacturer datasheet (cited, not reproduced)
materion-tube:
title: Materion Alloy 25 (C17200) Tube Data Sheet
id: Materion Performance Alloys and Composites, tube data sheet
url: https://voestalpine.com/specialtymetals/nam/app/uploads/sites/255/2024/07/Alloy-25-C17200-Tube-Data-Sheet.pdf
kind: datasheet
license: Manufacturer datasheet (cited, not reproduced)
usgs-mcs2026-beryllium:
title: 'Mineral Commodity Summaries 2026: Beryllium'
id: USGS MCS 2026
url: https://pubs.usgs.gov/periodicals/mcs2026/mcs2026-beryllium.pdf
year: 2026
kind: report
license: public domain (USGS)
aircraft-ams4533:
title: Beryllium Copper Alloy 25 (UNS C17200 / CDA 172) Technical Data Sheet, Aircraft Materials
id: AMS 4533, CDA 172
url: https://aircraftmaterials.com/data/copper/ams4533.html
kind: datasheet
license: Supplier data sheet (cited, not reproduced)
cornell-1910-1024:
title: 29 CFR 1910.1024 Beryllium, Cornell Legal Information Institute
url: https://www.law.cornell.edu/cfr/text/29/1910.1024
kind: standard
license: US federal regulation (public domain)
wikipedia-becu:
title: Beryllium copper, Wikipedia
url: https://en.wikipedia.org/wiki/Beryllium_copper
kind: web
license: CC BY-SA 4.0 (cited, not reproduced)
wikipedia-beryllium:
title: Beryllium, Wikipedia
url: https://en.wikipedia.org/wiki/Beryllium
kind: web
license: CC BY-SA 4.0 (cited, not reproduced)
harald-cube2:
title: Harald Pihl, Copper Alloy 25 / CuBe2 (CW101C) product page
url: https://www.haraldpihl.com/en/products/copper-alloys/cube2-cw101c/
kind: web
license: Supplier web page (cited, not reproduced)
voestalpine-c17200:
title: voestalpine Specialty Metals, C17200 BeCu / Alloy 25 product page
url: https://www.voestalpine.com/specialtymetals/nam/en/materials/c17200-becu-alloy-25/
kind: web
license: Supplier web page (cited, not reproduced)
license: CC-BY-4.0
updated: '2026-10-25'
review:
status: draft
method: assistant
checked_values: 20
unreachable: 1
caveats: 5
note: 'Values were read by an AI assistant on 2026-10-25 from the Materion datasheets (rod and bar, tube), extracted from the PDFs. Unreachable: the CDC NIOSH IDLH page (HTTP 403). Caveats: all mechanical and physical values are Materion''s nominal values for age-hardened stock of stated sizes, not minimum specification values; the Wikipedia corrosion and toxicity statements are qualitative; the OSHA limits come from the regulation text; the GHS box describes elemental beryllium, not the alloy; no space-environment data were found.'
story:
risk_groups:
- title: For people
lead: The alloy itself is a solid copper alloy, but processing it can release beryllium dust or fume, and that is the serious hazard.
level: 2
verdict: Serious inhalation hazard
points:
- label: Lungs
line: Inhaled beryllium can cause chronic beryllium disease, which restricts the exchange of oxygen between the lungs and the bloodstream. Materion says processing beryllium-containing alloys poses a health risk without safe practice.
- label: Limits
line: US law sets an 8-hour average limit of 0.2 µg/m3 and a 15-minute limit of 2.0 µg/m3, with an action level of 0.1 µg/m3.
- label: Carcinogen
line: IARC lists beryllium and its compounds as Category 1 carcinogens, according to Wikipedia.
- title: If it fails
lead: These failure routes come from the datasheets and are about temper and heat treatment, not corrosion failure.
points:
- label: Soft stock
line: Annealed rod and bar yields at 130 to 250 MPa, against 1000 to 1380 MPa for the aged AT and HT tempers.
- label: Wrong ageing
line: Materion gives its values only for the precipitation age-hardened condition, so a part aged outside the printed window is outside the quoted properties.
- title: Handling and storage
points:
- label: Follow the sheet
line: Read the Safety Data Sheet and Materion's beryllium safety guidance before working with the material.
- label: Specify the temper
line: Properties vary with diameter or thickness, so state the temper and size on every order.
why: Beryllium copper is used where a copper alloy must be strong and springy. Materion gives it as the highest-strength copper alloy, with conductivity considerably higher than other high-strength copper alloys, and it is non-magnetic and non-sparking. Its strength comes from age-hardening with 1.80 to 2.00 wt% beryllium, so the same alloy can be soft and easy to form in one temper and very strong in another. The price of that strength is beryllium, whose dust and fume are a serious health hazard.
uses:
- where: Bearings and bushings
line: Materion lists bushings and bearings for aircraft among the typical applications of its tube, and Wikipedia lists springs and load cells as uses where the alloy must keep its shape under repeated stress.
- where: Connectors and contacts
line: Materion lists circular and coaxial connectors, test probes and compression contacts among typical rod and bar applications.
can_do:
- label: Strength when aged
value: 1000 to 1380 MPa yield
benchmark: yield_strength
line: In the AT and HT tempers, the 0.2% offset yield strength is 1000 to 1210 MPa (AT) and 1100 to 1380 MPa (HT) for thin sections, according to Materion.
- label: Conductivity
value: 25 to 30 %IACS
benchmark: electrical_conductivity
line: Materion gives 25 to 30 %IACS for the age-hardened condition, against 5.8 to 6.9 µΩ-cm resistivity.
- label: Stiffness
value: 131 GPa
benchmark: elastic_modulus
line: The modulus of elasticity is 131 GPa (19,000 ksi) in the age-hardened condition.
- label: Weight
value: 8.36 g/cm3
benchmark: density
line: Density is 8.36 g/cm3 after heat treatment and 8.30 g/cm3 before it, per Materion's footnote.
- label: Non-magnetic
value: < 1.0006
benchmark: relative_magnetic_permeability
line: The tube datasheet gives a relative magnetic permeability below 1.0006.
compare: Materion describes C17200 as having the highest strength of any copper alloy, with electrical and thermal conductivity considerably greater than other high-strength copper alloys. The USGS says copper alloys with nickel and silicon, tin, titanium or phosphor bronze may replace beryllium-copper, but with reduced performance. Read the rows below as values for this alloy only.
compare_rows:
- label: Density
benchmark: density
- label: Yield strength
benchmark: yield_strength
- label: Electrical conductivity
benchmark: electrical_conductivity
handling:
- Specify the temper and size, because yield strength runs from 130 to 250 MPa in the annealed condition up to 1380 MPa when aged.
- Follow the Safety Data Sheet and treat all machining, grinding and fume as a beryllium exposure risk.
- Keep exposure below the OSHA limits of 0.2 µg/m3 (8-hour TWA) and 2.0 µg/m3 (15-minute short-term).
good_for:
- Springs, bushings and bearings that need high strength and a non-magnetic, non-sparking alloy
- Connectors, contacts and test probes that need strength together with conductivity
- 'Recycling: the USGS says scrap may supply as much as 20% to 25% of beryllium consumption'
watch_out:
- 'Beryllium dust, mist and fume: inhalation can cause chronic beryllium disease, and IARC lists beryllium as a Category 1 carcinogen'
- 'Temper matters: annealed stock is soft, and the high strengths need the printed ageing step'
- 'Supply is concentrated: the United States, Brazil, China and Nigeria produced about 99% of 2025 mine output in the USGS table (shares computed from the table, with rounded world total)'
- No space-environment test data were found for this alloy
verdict: Beryllium copper C17200 is a strong, conductive, non-magnetic copper alloy whose age-hardened tempers reach 1000 to 1380 MPa yield strength and 25 to 30 %IACS conductivity. Its beryllium content makes dust and fume a serious health hazard, and its strength depends on the temper chosen. This profile has no space-environment data.
recipe:
line: C17200 is a copper alloy (Cu) with 1.80 to 2.00 wt% beryllium, plus small amounts of nickel and cobalt. It is sold in a solution-annealed (A) condition and age-hardened to its high-strength tempers at 600 to 675 °F (315 to 357 °C) (Materion).
parts:
- name: Beryllium
symbol: Be
share: 1.80 to 2.00 wt%
role: The age-hardening element. Materion calls the alloy precipitation age-hardened, which gives the high-strength tempers.
- name: Nickel plus cobalt
symbol: Ni+Co
share: 0.20 wt% minimum
role: Minor additions. Materion sets a maximum of 0.6 wt% for nickel, cobalt and iron together.
- name: Copper
symbol: Cu
share: balance
role: The matrix and the main metal.
References
Every number above carries a reference number. Click one to see the source and where in it the value comes from.
| # | Source | Type | Year | Used for |
|---|---|---|---|---|
| Materion Alloy 25 (C17200) Rod and Bar Data Sheet, DS-AM-23 (2020) | datasheet | 2020 | 27 values | |
| Materion Alloy 25 (C17200) Tube Data Sheet | datasheet | 2 values | ||
| Mineral Commodity Summaries 2026: Beryllium | report | 2026 | 2 values | |
| Beryllium Copper Alloy 25 (UNS C17200 / CDA 172) Technical Data Sheet, Aircraft Materials | datasheet | 0 values | ||
| 29 CFR 1910.1024 Beryllium, Cornell Legal Information Institute | standard | 1 value | ||
| Beryllium copper, Wikipedia | web | 1 value | ||
| Beryllium, Wikipedia | web | 3 values | ||
| Harald Pihl, Copper Alloy 25 / CuBe2 (CW101C) product page | web | 0 values | ||
| voestalpine Specialty Metals, C17200 BeCu / Alloy 25 product page | web | 0 values |