{ "spore": "profile", "id": "magnesium-az31b", "spore_version": "0.2", "family": "magnesium-alloys", "name": "Magnesium alloy AZ31B", "abbreviation": "AZ31B", "role": "wrought structural alloy", "category": "metals", "type": "magnesium", "summary": "AZ31B is a wrought magnesium alloy with about 3 wt% aluminium and 1 wt% zinc. The stockist data sheet lists it as plate, sheet, rod and bar, with extrusions made to order. The USGS says magnesium's light weight is an advantage over aluminium and zinc in most wrought applications. Its weak point is corrosion in chloride solutions: in one 14-day test, uncoated AZ31 lost 9.7 mm per year in 5 M sodium chloride.\n", "best_for": "Light wrought sheet, plate and extrusions where weight matters and the part is kept out of chloride solutions. The stockist names aircraft fuselages and phone and laptop cases as uses.", "weakest_at": "Corrosion in chloride solutions (uncoated AZ31: 0.27 mm per year in 3.5 % NaCl and 9.7 mm per year in 5 M NaCl), and fire risk from magnesium metal (GHS statements for the element).", "identity": { "formula": "Wrought Mg-Al-Zn alloy: Al 2.5 to 3.5 wt%, Zn 0.7 to 1.3 wt%, Mn 0.2 min, Si max 0.05, Cu max 0.05, Ca max 0.04, Fe max 0.005, Ni max 0.005, other max 0.30 total, Mg balance. Nominal Mg 96, Al 3, Zn 1 (Goodfellow listing).", "designations": [ { "system": "Name", "code": "AZ31B" }, { "system": "Name", "code": "AZ31B-H24" }, { "system": "Name", "code": "AZ31B-H26" }, { "system": "Name", "code": "AZ31B-O" }, { "system": "UNS", "code": "M11311" }, { "system": "AMS", "code": "4375", "note": "AZ31B-O sheet, plate" }, { "system": "AMS", "code": "4376", "note": "AZ31B-H26 plate" }, { "system": "AMS", "code": "4377", "note": "AZ31B-H24 sheet, plate" }, { "system": "AMS", "code": "4382", "note": "AZ31B-O plate" }, { "system": "ASTM", "code": "B90" }, { "system": "ASTM", "code": "B107" }, { "system": "Name", "code": "QQ-M-44B" }, { "system": "Name", "code": "QQ-M-31B" }, { "system": "BS", "code": "3370 MAG-S-1110" }, { "system": "BS", "code": "3370 MAG-E-111M" }, { "system": "EN name", "code": "W.3504", "note": "aerospace" }, { "system": "EN name", "code": "WS 3.5312" }, { "system": "Name", "code": "EN1753 MG-P-62" }, { "system": "Name", "code": "AZ31", "note": "grade name, Goodfellow" }, { "system": "Name", "code": "MgAl3Zn1", "note": "Goodfellow synonym" }, { "system": "Name", "code": "AZ31B magnesium foil", "note": "Goodfellow synonym" } ], "source": "aircraftmaterials-az31b", "where": "Chemical Composition Limits table (AZ31B row) and Specifications list; UNS number and synonyms from the Goodfellow listing; Wikipedia composition table (AZ31B row)" }, "tags": { "environments": [], "stresses": [], "applications": [ "structures", "electronics-and-chips" ] }, "properties": [ { "benchmark": "density", "value": 1.8, "bound": "exact", "unit": "g/cm3", "scope": "material", "conditions": { "temperature": "not stated", "basis": "one value for the product group on the Goodfellow listing, printed rounded as 1.8" }, "method": "Physical Properties table of a supplier listing (foil and sheet product group)", "status": "ground", "source": "goodfellow-az31-foil", "where": "Physical Properties table, Density row (gcm-3)", "source_detail": { "title": "Goodfellow: AZ31 Magnesium Foil/Sheet, product listing with material properties", "url": "https://www.goodfellow.com/usa/az31-foil-group", "kind": "datasheet", "license": "Supplier web page, cited and not reproduced" } }, { "benchmark": "melting_point", "label": "Melting range", "value": 605, "value_high": 630, "bound": "range", "unit": "°C", "scope": "material", "conditions": { "basis": "range as printed on the listing" }, "method": "Thermal Properties table of a supplier listing", "status": "ground", "source": "goodfellow-az31-foil", "where": "Thermal Properties table, Melting point row", "source_detail": { "title": "Goodfellow: AZ31 Magnesium Foil/Sheet, product listing with material properties", "url": "https://www.goodfellow.com/usa/az31-foil-group", "kind": "datasheet", "license": "Supplier web page, cited and not reproduced" } }, { "benchmark": "specific_heat", "value": 1001, "bound": "exact", "unit": "J/(kg·K)", "scope": "material", "conditions": { "temperature": "not stated" }, "method": "Thermal Properties table of a supplier listing (printed as J K-1 kg-1)", "status": "ground", "source": "goodfellow-az31-foil", "where": "Thermal Properties table, Specific heat row", "source_detail": { "title": "Goodfellow: AZ31 Magnesium Foil/Sheet, product listing with material properties", "url": "https://www.goodfellow.com/usa/az31-foil-group", "kind": "datasheet", "license": "Supplier web page, cited and not reproduced" } }, { "benchmark": "thermal_conductivity", "value": 96, "bound": "exact", "unit": "W/(m·K)", "scope": "material", "conditions": { "temperature": "not stated" }, "method": "Thermal Properties table of a supplier listing (printed as W m-1 K-1)", "status": "ground", "source": "goodfellow-az31-foil", "where": "Thermal Properties table, Thermal conductivity row", "source_detail": { "title": "Goodfellow: AZ31 Magnesium Foil/Sheet, product listing with material properties", "url": "https://www.goodfellow.com/usa/az31-foil-group", "kind": "datasheet", "license": "Supplier web page, cited and not reproduced" } }, { "benchmark": "cte", "label": "Coefficient of thermal expansion, 20 to 100 °C", "value": 26, "bound": "exact", "unit": "ppm/K", "scope": "material", "conditions": { "temperature_range": "20 to 100 °C", "unit_in_source": "x10-6 K-1 (same as ppm/K)" }, "method": "Thermal Properties table of a supplier listing", "status": "ground", "source": "goodfellow-az31-foil", "where": "Thermal Properties table, Coefficient of thermal expansion row (printed 26 at 20-100 °C)", "source_detail": { "title": "Goodfellow: AZ31 Magnesium Foil/Sheet, product listing with material properties", "url": "https://www.goodfellow.com/usa/az31-foil-group", "kind": "datasheet", "license": "Supplier web page, cited and not reproduced" } }, { "benchmark": "elastic_modulus", "value": 45, "bound": "exact", "unit": "GPa", "scope": "material", "conditions": { "temper": "As Rolled (printed on the listing)", "product_form": "foil, film and sheet listing (a 0.25 mm disc is also listed)", "temperature": "not stated" }, "method": "Mechanical Properties table of a supplier listing", "status": "ground", "source": "goodfellow-az31-foil", "where": "Mechanical Properties table, Modulus of elasticity row", "source_detail": { "title": "Goodfellow: AZ31 Magnesium Foil/Sheet, product listing with material properties", "url": "https://www.goodfellow.com/usa/az31-foil-group", "kind": "datasheet", "license": "Supplier web page, cited and not reproduced" } }, { "benchmark": "ultimate_tensile_strength", "label": "Tensile strength, As Rolled foil and sheet listing", "value": 290, "bound": "exact", "unit": "MPa", "scope": "material", "conditions": { "temper": "As Rolled (printed on the listing; not O or H24)", "product_form": "foil, film and sheet listing", "temperature": "not stated" }, "method": "Mechanical Properties table of a supplier listing", "status": "ground", "source": "goodfellow-az31-foil", "where": "Mechanical Properties table, Tensile strength row", "source_detail": { "title": "Goodfellow: AZ31 Magnesium Foil/Sheet, product listing with material properties", "url": "https://www.goodfellow.com/usa/az31-foil-group", "kind": "datasheet", "license": "Supplier web page, cited and not reproduced" } }, { "benchmark": "elongation", "label": "Elongation at break, As Rolled foil and sheet listing", "value": 15, "bound": "exact", "unit": "%", "scope": "material", "conditions": { "temper": "As Rolled (printed on the listing; not O or H24)", "product_form": "foil, film and sheet listing", "temperature": "not stated" }, "method": "Mechanical Properties table of a supplier listing", "status": "ground", "source": "goodfellow-az31-foil", "where": "Mechanical Properties table, Elongation at break row", "source_detail": { "title": "Goodfellow: AZ31 Magnesium Foil/Sheet, product listing with material properties", "url": "https://www.goodfellow.com/usa/az31-foil-group", "kind": "datasheet", "license": "Supplier web page, cited and not reproduced" } }, { "benchmark": "hardness_brinell", "label": "Hardness, Brinell", "value": 73, "bound": "exact", "unit": "HB", "scope": "material", "conditions": { "temper": "As Rolled (printed on the listing; not O or H24)", "product_form": "foil, film and sheet listing" }, "method": "Mechanical Properties table of a supplier listing (printed as Hardness - Brinell)", "status": "ground", "note": "Not in spores/property-canon.yaml; the snake_case name hardness_brinell is used.", "source": "goodfellow-az31-foil", "where": "Mechanical Properties table, Hardness - Brinell row", "source_detail": { "title": "Goodfellow: AZ31 Magnesium Foil/Sheet, product listing with material properties", "url": "https://www.goodfellow.com/usa/az31-foil-group", "kind": "datasheet", "license": "Supplier web page, cited and not reproduced" } }, { "benchmark": "elongation", "label": "Elongation in 4D, H24 sheet, by thickness band", "value": 6, "value_high": 8, "bound": "range", "unit": "%", "scope": "material", "conditions": { "temper": "H24 (page condition: cold rolled, partially annealed)", "product_form": "sheet, thickness bands from 0.016 to 3.00 in", "basis": "elongation in 4D by thickness band" }, "method": "Typical Mechanical Properties table of a stockist technical data sheet", "status": "ground", "source": "aircraftmaterials-az31b", "where": "Typical Mechanical Properties table, Elongation in 4D (%) column, Cold Rolled partially annealed rows", "source_detail": { "title": "AircraftMaterialsUK technical data sheet: Magnesium Alloy AZ31B (composition, typical mechanical properties, specifications)", "url": "https://aircraftmaterials.com/data/magnesium/az31b.html", "kind": "datasheet", "license": "Stockist web page, cited and not reproduced" } }, { "benchmark": "corrosion_rate", "label": "Corrosion rate, uncoated AZ31, 3.5 % NaCl", "value": 0.27, "bound": "exact", "unit": "mm/year", "scope": "material", "conditions": { "alloy_as_tested": "AZ31 (Mg-Al 3 wt%, Zn 1 wt%, from Goodfellow), not AZ31B", "solution": "3.5 wt % NaCl (35 g/L)", "temperature": "37 °C", "exposure": "14 days immersion, mass loss" }, "method": "Immersion test; corrosion rate from mass loss over 14 days (the paper's equation)", "status": "ground", "note": "Not in spores/property-canon.yaml; the snake_case name corrosion_rate is used.", "source": "pmc-az31-corrosion", "where": "Results, paragraph on the 14-day immersion (AZ31 in 3.5% NaCl)", "source_detail": { "title": "Evaluation of Corrosion Performance of AZ31 Mg Alloy in Physiological and Highly Corrosive Solutions", "id": "PMC10952013; ACS Appl Bio Mater 2024, 7(3), 1735-1747", "url": "https://pmc.ncbi.nlm.nih.gov/articles/PMC10952013", "year": 2024, "kind": "paper", "license": "PMC copy of the journal article, cited and not reproduced" } }, { "benchmark": "corrosion_rate", "label": "Corrosion rate, uncoated AZ31, 5 M NaCl, continuous", "value": 9.7, "bound": "exact", "unit": "mm/year", "scope": "material", "conditions": { "alloy_as_tested": "AZ31 (Mg-Al 3 wt%, Zn 1 wt%), not AZ31B", "solution": "5 M NaCl (292 g/L), continuous immersion", "temperature": "37 °C", "exposure": "14 days immersion, mass loss" }, "method": "Immersion test; corrosion rate from mass loss over 14 days (the paper's equation)", "status": "ground", "source": "pmc-az31-corrosion", "where": "Results, paragraph on the 14-day immersion (continuous 5 M NaCl)", "source_detail": { "title": "Evaluation of Corrosion Performance of AZ31 Mg Alloy in Physiological and Highly Corrosive Solutions", "id": "PMC10952013; ACS Appl Bio Mater 2024, 7(3), 1735-1747", "url": "https://pmc.ncbi.nlm.nih.gov/articles/PMC10952013", "year": 2024, "kind": "paper", "license": "PMC copy of the journal article, cited and not reproduced" } }, { "benchmark": "corrosion_rate", "label": "Corrosion rate, uncoated AZ31, 5 M NaCl, intermittent", "value": 7.8, "bound": "exact", "unit": "mm/year", "scope": "material", "conditions": { "alloy_as_tested": "AZ31 (Mg-Al 3 wt%, Zn 1 wt%), not AZ31B", "solution": "5 M NaCl (292 g/L), intermittent (samples removed from the solution in the interrupted test)", "temperature": "37 °C", "exposure": "14 days immersion, mass loss" }, "method": "Immersion test; corrosion rate from mass loss over 14 days (the paper's equation)", "status": "ground", "source": "pmc-az31-corrosion", "where": "Results, paragraph on the 14-day immersion (intermittent 5 M NaCl)", "source_detail": { "title": "Evaluation of Corrosion Performance of AZ31 Mg Alloy in Physiological and Highly Corrosive Solutions", "id": "PMC10952013; ACS Appl Bio Mater 2024, 7(3), 1735-1747", "url": "https://pmc.ncbi.nlm.nih.gov/articles/PMC10952013", "year": 2024, "kind": "paper", "license": "PMC copy of the journal article, cited and not reproduced" } } ], "corrosion": [ { "environment": "Immersion in 3.5 % NaCl at 37 °C for 14 days (uncoated AZ31)", "headline": "Uncoated AZ31 corroded at 0.27 mm per year in 3.5 % NaCl.", "effect": "Mass-loss immersion gave 0.27 mm per year. The paper says the corrosion products formed in all the saline solutions it tested were similar.", "rating": "moderate", "conditions": { "temperature": "37 °C", "duration": "14 days", "basis": "mass loss; the rating is set by the profile writer from the rate, not from a standard" }, "source": "pmc-az31-corrosion", "where": "Results, 14-day immersion paragraph" }, { "environment": "Immersion in 5 M NaCl at 37 °C for 14 days, continuous and intermittent (uncoated AZ31)", "headline": "Uncoated AZ31 corroded at 9.7 mm per year in continuous 5 M NaCl.", "effect": "The study gives 9.7 mm per year for continuous 5 M NaCl and 7.8 mm per year for intermittent (interrupted) 5 M NaCl. The corrosion products were similar in all saline solutions.", "rating": "severe", "conditions": { "temperature": "37 °C", "duration": "14 days", "basis": "mass loss; the rating is set by the profile writer from the rate, not from a standard" }, "source": "pmc-az31-corrosion", "where": "Results, 14-day immersion paragraph; Methods, immersion tests" }, { "environment": "Chloride-rich saline environments (general statement, magnesium alloys)", "headline": "Chloride-rich saline environments are the main corrosion concern for magnesium alloys.", "effect": "The introduction of the study says susceptibility to corrosion, particularly in chloride-rich saline environments, compromises the structural integrity of magnesium alloys, and that the rapid emission of hydrogen gas and gas bubbles restrict their wider use.", "rating": "severe", "conditions": { "basis": "general statement in the introduction of the study, not a test result" }, "source": "pmc-az31-corrosion", "where": "Introduction, first paragraphs" }, { "environment": "5 M NaCl at 37 °C, intermittent, with a PF or PFS coating", "headline": "Coatings cut the rate to about 0.25 to 0.30 mm per year.", "effect": "PF (phosphate and fluoride) and PFS (phosphate, silicate and fluoride) soft-sparking coatings of 15 µm gave about 0.30 and 0.25 mm per year in intermittent 5 M NaCl. The paper says that is more than 30 times lower than uncoated AZ31 (7.8 mm per year in the same test).", "rating": "low", "conditions": { "coating": "PF or PFS, 15 µm", "temperature": "37 °C", "duration": "14 days", "basis": "mass loss, same method as the uncoated tests" }, "source": "pmc-az31-corrosion", "where": "Results, coated samples paragraph; Methods, sample preparation" } ], "risks": { "hazards": [ { "text": "PubChem's aggregated GHS reports for magnesium metal (2,205 company reports from 27 ECHA notifications) give H228 (flammable solid) in 44.9% of reports, H250 (catches fire spontaneously if exposed to air) in 36.5%, H260 (in contact with water releases flammable gases which may ignite spontaneously) in 36.7%, H261 (in contact with water releases flammable gas) in 44.8% and H252 (self-heating in large quantities; may catch fire) in 18%. 18.4% of reports (405 of 2,205) say the element does not meet GHS criteria. These are element-level statements, not a classification of the alloy as supplied.", "ghs": [ "H228", "H250", "H260", "H261", "H252" ], "source": "pubchem-mg", "where": "Safety and Hazards, GHS Classification (CID 5462224)" } ], "failure_risks": [ { "mode": "Chloride corrosion of uncoated AZ31", "trigger": "Immersion in chloride solutions (3.5 % and 5 M NaCl in the study)", "consequence": "Corrosion rate of 9.7 mm per year in continuous 5 M NaCl and 0.27 mm per year in 3.5 % NaCl; the study says susceptibility to corrosion compromises structural integrity", "severity": "high", "source": "pmc-az31-corrosion", "where": "Results, 14-day immersion paragraph; Introduction" }, { "mode": "Hydrogen gas evolution during corrosion", "trigger": "Degradation of magnesium alloys in chloride-rich saline environments", "consequence": "Rapid emission of hydrogen gas and gas bubble formation; the study says this restricts wider use in tissue", "severity": "moderate", "source": "pmc-az31-corrosion", "where": "Introduction, first paragraphs" }, { "mode": "Fire or flammable gas from magnesium metal", "trigger": "Contact with water (H260, H261) or exposure to air of pyrophoric forms (H250)", "consequence": "The GHS statements say the element can release flammable gas, catch fire spontaneously or be a flammable solid (element-level, not the alloy as supplied)", "severity": "high", "source": "pubchem-mg", "where": "GHS Classification (CID 5462224)" }, { "mode": "Lower yield and maximum stress along the rolling direction (H24 sheet)", "trigger": "Tensile loading parallel to the rolling direction", "consequence": "Yield and maximum stress are lower than for loading across the rolling direction; both fall as the test temperature rises (room temperature to 400 °C)", "severity": "moderate", "source": "hereon-az31-h24-tension", "where": "Abstract" } ], "side_effects": [], "handling": [ { "text": "The GHS statements say that contact with water releases flammable gas (H261). Keep the metal dry and away from water.", "source": "pubchem-mg", "where": "GHS Classification, H261 and H260 statements (CID 5462224)" }, { "text": "Goodfellow's listing says a safety data sheet is available. Read the SDS for the exact product before cutting, grinding or welding.", "source": "goodfellow-az31-foil", "where": "Product page, SDS notice" }, { "text": "Uncoated AZ31 corrodes fast in chloride solutions. Keep uncoated parts out of salt water.", "source": "pmc-az31-corrosion", "where": "Results, 14-day immersion paragraph" } ], "mitigations": [ { "text": "In the PMC study, PF and PFS soft-sparking coatings of 15 µm cut the intermittent 5 M NaCl rate to about 0.30 and 0.25 mm per year, more than 30 times lower than uncoated AZ31 (7.8 mm per year).", "source": "pmc-az31-corrosion", "where": "Results, coated samples paragraph; Methods, sample preparation" } ] }, "uses": [ { "application": "structures", "device": "Aircraft fuselages", "example": "The stockist data sheet names aircraft fuselages among the uses of AZ31B.", "source": "aircraftmaterials-az31b", "where": "Technical data sheet, description paragraph" }, { "application": "electronics-and-chips", "device": "Cell phone and laptop cases", "example": "The same data sheet names cell phone and laptop cases, with speaker cones and concrete tools.", "source": "aircraftmaterials-az31b", "where": "Technical data sheet, description paragraph" } ], "supply": [ { "subject": "Magnesium metal, world primary (smelter) production", "abundance": "USGS: resources for magnesium range from large to virtually unlimited and are globally widespread; magnesium-bearing brines are estimated to be a resource in the billions of tons.", "producers": [ { "country": "China", "share_percent": 87.7, "year": 2025 }, { "country": "Russia", "share_percent": 5.5, "year": 2025 }, { "country": "Brazil", "share_percent": 1.8, "year": 2025 }, { "country": "Israel", "share_percent": 1.8, "year": 2025 }, { "country": "Turkey", "share_percent": 1.4, "year": 2025 }, { "country": "Kazakhstan", "share_percent": 1.2, "year": 2025 }, { "country": "Iran", "share_percent": 0.5, "year": 2025 }, { "country": "United States", "share_percent": 0, "year": 2025 } ], "critical_lists": [ { "list": "USGS 2025 final List of Critical Minerals (magnesium; page read through the fetch tool)", "listed": true } ], "recycling": "USGS: about 110 thousand metric tons of secondary magnesium was recovered from scrap in 2025 (estimate). The only US primary smelter, in Utah, stopped in 2022.", "substitutes": [ "USGS: aluminium and zinc may substitute for magnesium in castings and wrought products. Magnesium's light weight is an advantage over them in most applications; its high cost is a disadvantage." ], "source": "usgs-mcs2026-magnesium-metal", "where": "World Primary Production and Reserves table, smelter production 2025 (world total 1,100 thousand t, rounded; shares calculated by Space Mushroom over the listed 2025 values, sum 1,083 thousand t). Recycling; Substitutes. Domestic Production and Use: about 69% of 2025 primary consumption went into castings, principally automotive. Salient Statistics: US net import reliance above 75% of apparent consumption (2025 estimate)." }, { "subject": "Magnesium metal imported to the United States, 2021 to 2024 (99.8 % purity)", "producers": [ { "country": "Israel", "share_percent": 47 }, { "country": "Turkey", "share_percent": 31 }, { "country": "Russia", "share_percent": 8 }, { "country": "China", "share_percent": 6 } ], "critical_lists": [], "substitutes": [], "source": "usgs-mcs2026-magnesium-metal", "where": "Import Sources (2021 to 2024), magnesium metal (99.8% purity) row; the other 8% is not listed by country" } ], "media": [], "documents": [ { "title": "AircraftMaterialsUK technical data sheet: Magnesium Alloy AZ31B", "type": "datasheet", "url": "https://aircraftmaterials.com/data/magnesium/az31b.html" }, { "title": "Goodfellow: AZ31 Magnesium Foil/Sheet, product listing with material properties", "type": "datasheet", "url": "https://www.goodfellow.com/usa/az31-foil-group" }, { "title": "USGS Mineral Commodity Summaries 2026: Magnesium Metal", "type": "report", "url": "https://pubs.usgs.gov/periodicals/mcs2026/mcs2026-magnesium-metal.pdf", "year": 2026 }, { "title": "USGS: About the 2025 List of Critical Minerals", "type": "report", "url": "https://www.usgs.gov/programs/mineral-resources-program/science/about-2025-list-critical-minerals", "year": 2025 }, { "title": "PubChem: Magnesium, CID 5462224, Safety and Hazards, GHS Classification", "type": "database", "url": "https://pubchem.ncbi.nlm.nih.gov/compound/5462224" }, { "title": "Evaluation of Corrosion Performance of AZ31 Mg Alloy in Physiological and Highly Corrosive Solutions (ACS Appl Bio Mater, 2024)", "type": "paper", "url": "https://pmc.ncbi.nlm.nih.gov/articles/PMC10952013", "year": 2024 }, { "title": "Hereon publications record: Effect of temperature on tensile properties of hot rolled AZ31 Mg alloy sheets (Balik, Lukac, Bohlen, Kainer; Kovove materialy 2007)", "type": "paper", "url": "https://publications.hereon.de/id/26479/index.php", "year": 2007 }, { "title": "DLR eLib record: Influence of tension-compression asymmetry on the mechanical behavior of AZ31B magnesium alloy sheets in bending (2016)", "type": "paper", "url": "https://elib.dlr.de/98810/", "year": 2016 }, { "title": "Wikipedia: Magnesium alloy (compositions table)", "type": "database", "url": "https://en.wikipedia.org/wiki/Magnesium_alloy" } ], "gaps": [ "O-temper strength: no readable source with a printed unit was found. The Alloys International AZ31B-O page is rendered in the browser (no values in the HTML). MakeItFrom (a JavaScript and cookie check) and SuppliersOnline (no content) could not be read with curl, and the Smiths datasheet link returned an error page.", "ASTM B90 (sheet and plate) and ASTM B107 (extrusions) minimums: the standards are paywalled and were not read. The copy of an older revision found on a university server was not used.", "H24 yield and tensile strength are not recorded. The one stockist page that lists them prints no unit. No source read in this run gives a yield strength for AZ31B.", "The Goodfellow values are for the foil and sheet listing with temper As Rolled, not O or H24. Density is printed rounded (1.8), and the thermal and specific heat values give no test temperature (the CTE range is 20 to 100 °C).", "Not found in a readable source: Poisson's ratio, shear modulus, electrical resistivity, compressive yield, cryogenic and space-environment data, outgassing, and an ignition temperature for chips or dust.", "Property names: hardness_brinell and corrosion_rate are not in spores/property-canon.yaml and are used as snake_case names.", "The Hereon H24 study (room temperature to 400 °C) and the DLR record (AZ31B-O sheet in tension, compression and bending) were read as abstracts only. Their numbers were not reachable.", "The DTIC report ADA494926 (AZ31B-H24 plate, Army Research Lab and Magnesium Elektron) returned a blocked page to curl, so its plate values are not used.", "The International Magnesium Association page on magnesium as the lightest structural metal returned a bot-check page, so that phrase is not used. The USGS wording (lighter than aluminium and zinc in most applications) is used instead.", "EU critical raw materials: the Commission page fetched did not show the list entries, so no EU listing is recorded.", "Corrosion rates come from a biomedical study of AZ31 (Goodfellow composition Mg-Al 3 wt%, Zn 1 wt%), 14-day immersion at 37 °C by mass loss. No standard corrosion test of AZ31B was found.", "No safety data sheet for the alloy was opened. The PubChem GHS data are element-level and do not cover dust or fume from machining or welding.", "The Wikipedia composition row marks manganese 0.2 with a question mark, so Wikipedia is used only for the composition row. The stockist's Mn 0.2 min is the value used." ], "story": { "why": "AZ31B is a wrought magnesium alloy, which the stockist describes as having good room-temperature strength and ductility, with corrosion resistance and weldability. The Goodfellow listing gives the nominal composition as Mg 96, Al 3, Zn 1, and the stockist gives aluminium at 2.5 to 3.5 wt% and zinc at 0.7 to 1.3 wt%. The stockist also says most magnesium alloys are not heat treatable like aluminium. Magnesium's light weight is an advantage over aluminium and zinc in most wrought applications, according to the USGS. About 69% of the primary magnesium consumed in 2025 went into castings, principally automotive, so the wrought sheet, plate and extrusion this profile covers is a smaller part of the market.", "uses": [ { "where": "Aircraft structure", "line": "The AircraftMaterials data sheet names aircraft fuselages among the uses of AZ31B." }, { "where": "Phone and laptop cases", "line": "The same data sheet names cell phone and laptop cases, with speaker cones and concrete tools." }, { "where": "Superformed automotive parts", "line": "The data sheet says AZ31B can be superformed at elevated temperatures into intricate components for automotive uses." } ], "can_do": [ { "label": "Weight", "line": "The Goodfellow listing gives density as 1.8 g/cm3. The USGS says magnesium's light weight is an advantage over aluminium and zinc in most wrought applications.", "benchmark": "density", "scope": "material", "value": "1.8 g/cm3" }, { "label": "Strength, as rolled listing", "line": "The Goodfellow listing for foil and sheet, with temper As Rolled, gives 290 MPa tensile strength and 15 % elongation at break.", "benchmark": "ultimate_tensile_strength", "scope": "material", "value": "290 MPa tensile" }, { "label": "Heat conduction", "line": "Thermal conductivity is 96 W/(m·K) on the Goodfellow listing, at a temperature the listing does not state.", "benchmark": "thermal_conductivity", "scope": "material", "value": "96 W/(m·K)" }, { "label": "Thermal expansion", "line": "The Goodfellow listing gives a mean coefficient of thermal expansion of 26 ppm/K over 20 to 100 °C.", "benchmark": "cte", "scope": "material", "value": "26 ppm/K" }, { "label": "Corrosion in salt water", "line": "Uncoated AZ31 lost 0.27 mm per year in 3.5 % NaCl over 14 days at 37 °C in the PMC study.", "benchmark": "corrosion_rate", "scope": "material", "value": "0.27 mm/year" } ], "compare": "The USGS says aluminium and zinc can substitute for magnesium in castings and wrought products, and that magnesium's light weight is an advantage over them in most applications, although its high cost is a disadvantage. This profile holds no strength-per-mass figures for aluminium or zinc, so it does not rank AZ31B against them. The stockist says most magnesium alloys are not heat treatable like aluminium, and its H24 rows are cold rolled and partially annealed.", "compare_rows": [ { "label": "Density", "benchmark": "density", "scope": "material" }, { "label": "Thermal conductivity", "benchmark": "thermal_conductivity", "scope": "material" }, { "label": "Thermal expansion", "benchmark": "cte", "scope": "material" } ], "handling": [ "Keep the metal dry. The GHS statements say contact with water releases flammable gas (H261 in 44.8% of reports).", "Read the supplier's safety data sheet before cutting, grinding or welding. The Goodfellow listing offers one.", "Keep uncoated parts out of chloride solutions. The PMC study lost 9.7 mm per year in continuous 5 M NaCl.", "If chloride exposure cannot be avoided, the study's PF or PFS coatings cut the rate to about 0.25 to 0.30 mm per year in intermittent 5 M NaCl." ], "good_for": [ "Light sheet and plate parts. Density is 1.8 g/cm3 on the Goodfellow listing.", "Aircraft fuselage and phone or laptop case parts, the two uses named on the stockist data sheet.", "Parts that are formed hot. The stockist says AZ31B can be superformed at elevated temperatures into intricate components." ], "watch_out": [ "Corrosion in chloride. Uncoated AZ31 lost 9.7 mm per year in continuous 5 M NaCl and 0.27 mm per year in 3.5 % NaCl (14 days at 37 °C, PMC study).", "Direction and temperature. The Hereon study of H24 sheet, tested from room temperature to 400 °C, found yield and maximum stress lower along the rolling direction than across it, and both fall as the temperature rises.", "Temper. The 290 MPa tensile value is for the As Rolled listing, not O or H24, and no O-temper strength was found in a readable source.", "Fire. The GHS statements for magnesium metal include flammable solid (H228) and catches fire spontaneously if exposed to air (H250)." ], "verdict": "AZ31B is a light, weldable wrought magnesium alloy that the stockist names for aircraft fuselages and phone and laptop cases. Its weak point is corrosion in salt solutions: uncoated AZ31 corroded fast in the PMC study. The strength figures here are a listing and typical values, and no O-temper value was found.", "recipe": { "line": "Wrought magnesium alloy with aluminium and zinc additions. The stockist data sheet gives Al 2.5 to 3.5 wt%, Zn 0.7 to 1.3 wt%, Mn 0.2 min, magnesium as the balance, and maximum limits on silicon, copper, calcium, iron and nickel. The Goodfellow listing gives the nominal formula Mg 96, Al 3, Zn 1. The data sheet says the alloy is available as plate, tooling plate, sheet, rod and bar, with extrusions made to order.", "parts": [ { "name": "Magnesium", "symbol": "Mg", "role": "The base metal and the balance of the alloy.", "share_note": "balance (the rest)", "source": "aircraftmaterials-az31b", "where": "Chemical Composition Limits table, Mg row (bal)" }, { "name": "Aluminium", "symbol": "Al", "role": "Main alloying addition.", "share_percent": 2.5, "share_high": 3.5, "source": "aircraftmaterials-az31b", "where": "Chemical Composition Limits table, Al row" }, { "name": "Zinc", "symbol": "Zn", "role": "Second alloying addition.", "share_percent": 0.7, "share_high": 1.3, "source": "aircraftmaterials-az31b", "where": "Chemical Composition Limits table, Zn row" }, { "name": "Manganese", "symbol": "Mn", "role": "Minor addition, minimum limit.", "share_percent": 0.2, "share_note": "minimum (0.2 min on the data sheet)", "source": "aircraftmaterials-az31b", "where": "Chemical Composition Limits table, Mn row" }, { "name": "Impurity limits", "symbol": "Si, Cu, Ca, Fe, Ni", "role": "Limits on impurities; the alloy is made to these maxima.", "share_note": "maximum: Si 0.05, Cu 0.05, Ca 0.04, Fe 0.005, Ni 0.005; other elements 0.30 total", "source": "aircraftmaterials-az31b", "where": "Chemical Composition Limits table, Si, Cu, Ca, Fe, Ni and Others rows" } ] }, "risk_groups": [ { "title": "For people", "lead": "The only hazard data opened is PubChem's GHS data for magnesium metal. It is element-level, not a classification of AZ31B as supplied.", "points": [ { "label": "Fire statements", "line": "Magnesium metal is listed as a flammable solid (H228), as catching fire spontaneously if exposed to air (H250), and as releasing flammable gases on contact with water (H260, H261). Self-heating is also reported (H252)." } ], "gap": "No safety data sheet for the alloy was opened, and no dust or fume data for machining or welding was found." }, { "title": "If it fails", "lead": "The failure routes come from the corrosion tests, the study's introduction and the GHS statements.", "points": [ { "label": "Chloride corrosion", "line": "Uncoated AZ31 corroded at 0.27 mm per year in 3.5 % NaCl and 9.7 mm per year in continuous 5 M NaCl in the 14-day tests." }, { "label": "Hydrogen gas", "line": "The study's introduction says the rapid emission of hydrogen gas and gas bubbles restricts wider use of magnesium alloys in tissue." }, { "label": "Rolling direction", "line": "The Hereon study of H24 sheet found lower yield and maximum stress along the rolling direction than across it." } ] }, { "title": "Handling and storage", "points": [ { "label": "Water", "line": "Contact with water releases flammable gas (H261), so keep the metal dry." }, { "label": "Chlorides", "line": "Uncoated AZ31 corrodes fast in chloride solutions. PF and PFS coatings cut the rate in the study." } ] } ] }, "updated": "2026-10-24", "review": { "status": "draft", "method": "assistant", "checked_values": 15, "unreachable": 0, "caveats": 7, "note": "Written 2026-10-24 from pages fetched in this run (curl and the fetch tool). Values are as printed. The H24 strengths of one stockist page were left out because it prints no unit. Caveats: Goodfellow density rounded (1); corrosion rates are for AZ31, not AZ31B (3 values)." }, "sources": { "aircraftmaterials-az31b": { "title": "AircraftMaterialsUK technical data sheet: Magnesium Alloy AZ31B (composition, typical mechanical properties, specifications)", "url": "https://aircraftmaterials.com/data/magnesium/az31b.html", "kind": "datasheet", "license": "Stockist web page, cited and not reproduced" }, "goodfellow-az31-foil": { "title": "Goodfellow: AZ31 Magnesium Foil/Sheet, product listing with material properties", "url": "https://www.goodfellow.com/usa/az31-foil-group", "kind": "datasheet", "license": "Supplier web page, cited and not reproduced" }, "usgs-mcs2026-magnesium-metal": { "title": "USGS Mineral Commodity Summaries 2026: Magnesium Metal", "id": "USGS MCS 2026, February 2026", "url": "https://pubs.usgs.gov/periodicals/mcs2026/mcs2026-magnesium-metal.pdf", "year": 2026, "kind": "report", "license": "public domain (USGS)" }, "usgs-crit2025": { "title": "About the 2025 List of Critical Minerals (USGS, final list)", "url": "https://www.usgs.gov/programs/mineral-resources-program/science/about-2025-list-critical-minerals", "year": 2025, "kind": "web", "license": "public domain (USGS)" }, "pubchem-mg": { "title": "Magnesium, PubChem compound CID 5462224: Safety and Hazards, GHS Classification", "id": "PubChem CID 5462224; aggregated from ECHA C&L notifications", "url": "https://pubchem.ncbi.nlm.nih.gov/compound/5462224", "kind": "database", "license": "PubChem (NCBI) public data" }, "pmc-az31-corrosion": { "title": "Evaluation of Corrosion Performance of AZ31 Mg Alloy in Physiological and Highly Corrosive Solutions", "id": "PMC10952013; ACS Appl Bio Mater 2024, 7(3), 1735-1747", "url": "https://pmc.ncbi.nlm.nih.gov/articles/PMC10952013", "year": 2024, "kind": "paper", "license": "PMC copy of the journal article, cited and not reproduced" }, "hereon-az31-h24-tension": { "title": "Effect of temperature on tensile properties of hot rolled AZ31 Mg alloy sheets (Balik, Lukac, Bohlen, Kainer), Kovove materialy / Metallic materials 45 (2007) 135-140", "url": "https://publications.hereon.de/id/26479/index.php", "year": 2007, "kind": "paper", "license": "Hereon publications repository record (abstract read)" }, "dlr-az31b-bending": { "title": "Influence of tension-compression asymmetry on the mechanical behavior of AZ31B magnesium alloy sheets in bending (DLR eLib record)", "url": "https://elib.dlr.de/98810/", "year": 2016, "kind": "paper", "license": "DLR eLib repository record (abstract read)" }, "wikipedia-magnesium-alloy": { "title": "Wikipedia: Magnesium alloy (compositions table, AZ31B row)", "url": "https://en.wikipedia.org/wiki/Magnesium_alloy", "kind": "web", "license": "CC BY-SA (Wikipedia), cited for composition only" } }, "license": "CC-BY-4.0", "url": "https://spacemushroom.com/profiles/magnesium-az31b/" }