Magnesium Alloy EV31A
ASTM EV31A · UNS M12310
EV31A (Elektron 21, UNS M12310) is a Mg-Nd-Gd-Zr rare-earth casting alloy developed for strength, creep resistance and corrosion resistance up to about 200 °C, supplied as-cast or in T6.
Values for the As Cast condition
EV31A tempers and conditions
EV31A is supplied in 2 conditions, soft to hard. As Cast is the default FabDigit quotes; the values on this page are for it.
Compare all 2 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
As CastDefault no heat treatment after casting | Untreated foundry condition, used only for non-structural parts or as the starting point before T6 solution treatment and ageing. | 110 | 195 | 4 | 55 HB | 9.5 % IACS |
Solution heat treated and artificially aged | Standard supply and design condition for aerospace EV31A castings (AMS 4429 / ASTM B80) — best combination of room- and elevated-temperature strength. | 172 | 280 | 5 | 70 HB | — |
What is EV31A?
EV31A (Elektron 21, UNS M12310) is a Mg-Nd-Gd-Zr rare-earth casting alloy developed for strength, creep resistance and corrosion resistance up to about 200 °C, supplied as-cast or in T6. As-cast values are 110 MPa yield, 195 MPa tensile strength, 4 % elongation and 55 HB, with a default maximum service temperature of 150 °C; T6 is used where higher properties are needed. It is a casting-only alloy, not wrought, and rare-earth additions make it more expensive than AZ91 or AM60B. WE43 is the alternative for higher temperatures and greater ductility. EV31A has a density of 1.82 g/cm³ (0.0658 lb/in³), heavier than 74% of magnesium alloy grades. It melts at 545°C (1,013 °F). EV31A has a yield strength of 110 MPa (16 ksi) and a tensile strength of 195 MPa (28.3 ksi) — weaker than 83% of magnesium alloy grades. Elongation at break is 4% and the elastic modulus is 44 GPa (6.38 Msi).
What is EV31A used for?
- Aircraft engine casings
- Helicopter transmission housings
- Motorsport gearbox castings
- Auxiliary gearbox covers
- Pump and actuator bodies
- Structural aerospace sand castings
Limitations
- Low electrical conductivity — 9.5 % IACS, worse than 100% of magnesium alloy grades
- High embodied carbon — 42 kg CO₂/kg, worse than 99% of magnesium alloy grades
- Low strength — 110 MPa (16 ksi), worse than 83% of magnesium alloy grades
EV31A properties
Typical room-temperature values for EV31A-As Cast; bars are the position among magnesium alloy grades.
Physical3
EV31A has a density of 1.82 g/cm³ (0.0658 lb/in³), heavier than 74% of magnesium alloy grades. It melts at 545°C (1,013 °F).
Mechanical14
EV31A has a yield strength of 110 MPa (16 ksi) and a tensile strength of 195 MPa (28.3 ksi) — weaker than 83% of magnesium alloy grades. Elongation at break is 4% and the elastic modulus is 44 GPa (6.38 Msi).
Thermal6
EV31A is rated for continuous service to 150°C (302 °F). It conducts heat at 100 W/m·K (57.8 BTU/hr·ft·°F), better than 57% of magnesium alloy grades. Thermal expansion is 26.7 µm/m·K (14.8 µin/in·°F).
Electrical3
EV31A conducts electricity at 9.5 % IACS, worse than 100% of magnesium alloy grades.
Chemical & Environmental3
Corrosion resistance is poor (30/100), better than 88% of magnesium alloy grades.
Sustainability4
Producing a kilogram of EV31A takes about 400 MJ of energy and emits 42 kg of CO₂ — more than 98% of magnesium alloy grades. Typical recycled content is 15%.
Manufacturability8
EV31A's machinability is excellent (90/100, worse than 95% of magnesium alloy grades); weldability very good (72/100); formability not recommended (10/100).
Common Calculations5
Values are nominal handbook figures for design screening. Certified mill or lot data ships with every FabDigit order on request.
Strength versus weight in the magnesium alloy family
Yield strength against density for every magnesium alloy grade FabDigit runs. EV31A is highlighted; hover a dot for its name, or open the interactive family chart.
Working with EV31A
Is EV31A easy to machine?
Machines very easily with sharp carbide tools, high speeds and generous rake; use dry or mineral-oil coolant (never water-based) and manage fine chips to avoid ignition.
Can EV31A be welded?
TIG/GTAW repair-weldable with matching EV31A filler under argon; solution/ageing (T6) should be re-applied or a local post-weld age used to restore properties.
Can EV31A be formed, bent or molded?
Sand, investment and permanent-mould casting alloy with good fluidity and low hot-tearing tendency; use protective cover gas (SF6-free alternatives) and 0.6–1.0 % Zr grain refinement — not a wrought/formable alloy.
Manufacturability
The process limits FabDigit's quote engine applies to EV31A. Design inside these and the part quotes instantly; outside them it routes to an engineer.
CNC machining
| Machinability | Excellent90 / 100 |
|---|---|
| ISO material group | N.7 |
| Cutting speed (rough / finish) | 400 / 460 m/min |
| Minimum wall | 0.8 mm |
| Minimum internal radius | 1.5 mm |
| Drill depth limit | 8× diameter |
| Best surface (machined / polished) | Ra 0.8 / — |
| Hardenable after machining | No |
EV31A chemical composition (wt %)
Limits by weight percent from the governing specification, written the way the spec states them — a single maximum for impurities, a range for alloying elements, and the base element as balance. Nominal is the typical mid-range value.
| Element | Spec limit (wt %) | Nominal |
|---|---|---|
| Ndprincipal RE strengthener | 2.6 – 3.1 | 2.85 |
| Gdheavy RE for elevated-temperature stability | 1 – 1.7 | 1.3 |
| Zn | 0.2 – 0.5 | 0.35 |
| Zrgrain refiner | 0.4 – 1 | 0.6 |
| Feimpurity limit | ≤ 0.01 | |
| Cuimpurity limit | ≤ 0.03 | |
| Niimpurity limit | ≤ 0.01 | |
| Siimpurity limit | ≤ 0.01 | |
| Others (each)total others 0.30 max | ≤ 0.01 | |
| Mg | balance |
What surface finishes work on EV31A?
Apply chromate-free conversion coat plus epoxy primer/topcoat, or plasma-electrolytic (Keronite/Tagnite) coating; insulate all joints to steel or carbon fibre to prevent galvanic attack.
Surface treatments FabDigit runs on magnesium alloy parts — pick them in the quote configurator or call them out on the drawing. Each links to its datasheet in the surface-finish library (thickness, specs, call-out, material verdicts).
Conversion Coating
Organic Coating
Equivalent designations
Standards and trade names that resolve to Magnesium Alloy EV31A in FabDigit's catalog. Equivalence is nominal — check the exact specification when certification matters.
- UNS
- M12310
- Trade names
- Elektron 21
- Also called
- EV31A-T6
How much does EV31A cost?
EV31A is a standard-cost magnesium alloy ($$), cheaper than about 59% of the materials FabDigit quotes. Part price depends far more on geometry, tolerance and quantity than on the raw stock — upload a CAD file for a live quote.
EV31A — frequently asked
What is EV31A used for?
EV31A is typically used for aircraft engine casings, helicopter transmission housings, motorsport gearbox castings, auxiliary gearbox covers, pump and actuator bodies and structural aerospace sand castings. In short: high-temp powertrain magnesium.
What is the yield strength of EV31A?
EV31A has a typical yield strength of 110 MPa (16 ksi) and a tensile strength of 195 MPa (28.3 ksi) — weaker than 83% of magnesium alloy grades. Strength varies by condition: see the 2 listed tempers.
Is EV31A easy to machine?
Yes — machinability is rated excellent (90/100, worse than 95% of magnesium alloy grades). Machines very easily with sharp carbide tools, high speeds and generous rake; use dry or mineral-oil coolant (never water-based) and manage fine chips to avoid ignition.
Can EV31A be welded?
Yes — weldability is rated very good (72/100). TIG/GTAW repair-weldable with matching EV31A filler under argon; solution/ageing (T6) should be re-applied or a local post-weld age used to restore properties.
What surface finishes work on EV31A?
Apply chromate-free conversion coat plus epoxy primer/topcoat, or plasma-electrolytic (Keronite/Tagnite) coating; insulate all joints to steel or carbon fibre to prevent galvanic attack.
Can EV31A be formed, bent or molded?
Sand, investment and permanent-mould casting alloy with good fluidity and low hot-tearing tendency; use protective cover gas (SF6-free alternatives) and 0.6–1.0 % Zr grain refinement — not a wrought/formable alloy.
What is the maximum service temperature of EV31A?
EV31A is rated for continuous use to about 150°C (302 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
What is the difference between EV31A As Cast and EV31A-T6?
As Cast is the default condition — untreated foundry condition, used only for non-structural parts or as the starting point before T6 solution treatment and ageing. T6: standard supply and design condition for aerospace EV31A castings (AMS 4429 / ASTM B80) — best combination of room- and elevated-temperature strength. Yield strength is 110 MPa in As Cast versus 172 MPa in T6.
How much does EV31A cost?
EV31A is a standard-cost magnesium alloy ($$), cheaper than about 59% of the materials FabDigit quotes. Part price depends far more on geometry, tolerance and quantity than on the raw stock — upload a CAD file for a live quote.
Can FabDigit make parts in EV31A?
Yes — EV31A is available for CNC machining with instant online pricing. Upload a STEP file to get a price and a DFM check.
Sources
- Elektron 21 (EV31A) alloy datasheet — Magnesium Elektron / Luxfer MEL Technologies (2020)
- AMS 4429 — Magnesium Alloy Castings, EV31A-T6 — SAE International (2018)
- ASTM B80 — Standard Specification for Magnesium-Alloy Sand Castings — ASTM (2020)
- ASM Handbook Vol. 2 — Properties and Selection: Nonferrous Alloys — ASM International (1990)
Property data is compiled from published supplier and standards handbooks and normalised for comparison; hardness values on non-Brinell scales are converted approximately for charting only. Manufacturability limits are FabDigit quote-engine defaults and may be relaxed by engineering review. Nothing on this page is a certification — request mill certs, CoC or material test reports with your order.