Magnesium Alloy AM100A-T7
Temper
ASTM AM100A · UNS M10100
T7 = solution heat treated and overaged (stabilized)
Choose for dimensional stability and reduced residual stress in castings that see moderate service heat or tight tolerances, trading some strength for stability.
Values for the T7 condition
Other AM100A tempers and conditions
AM100A is listed in 5 conditions; see the grade overview at AM100A.
Compare all 5 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
As fabricated | Lowest-cost condition for lightly loaded, dimensionally stable castings where no heat treatment is justified. | 83 | 150 | 2 | 53 HB | 68 W/m·K |
Solution heat treated and naturally aged | Pick when maximum toughness/ductility and shock resistance matter more than yield strength. | 83 | 275 | 10 | 53 HB | 66 W/m·K |
T7This page Solution heat treated and overaged (stabilized) | Choose for dimensional stability and reduced residual stress in castings that see moderate service heat or tight tolerances, trading some strength for stability. | 110 | 250 | 4 | 63 HB | — |
T6Default Solution heat treated and artificially aged | Standard supply condition: highest yield strength and hardness, accepted at the cost of very low elongation. | 152 | 275 | 1 | 69 HB | 72 W/m·K |
T6 variant, underaged | Use where the maximum hardness and compressive yield of AM100A are needed on thicker permanent-mold sections. | 160 | 275 | 1 | 74 HB | 73 W/m·K |
What is AM100A-T7?
AM100A-T7 is AM100A in the T7 temper — choose for dimensional stability and reduced residual stress in castings that see moderate service heat or tight tolerances, trading some strength for stability. AM100A-T7 has a yield strength of 110 MPa (16 ksi) and a tensile strength of 250 MPa (36.3 ksi) — weaker than 83% of magnesium alloy grades. Elongation at break is 4% and the elastic modulus is 45 GPa (6.53 Msi). AM100A-T7 has a density of 1.81 g/cm³ (0.0654 lb/in³), heavier than 58% of magnesium alloy grades. It melts at 465°C (869 °F). T6 is the default condition FabDigit quotes; T7 is available on request or by drawing note.
Limitations
- Hard to polish — 45/100, worse than 93% of magnesium alloy grades
- Low fracture toughness — 12 MPa·√m (10.9 ksi·√in), worse than 92% of magnesium alloy grades
- Low strength — 110 MPa (16 ksi), worse than 83% of magnesium alloy grades
- Low electrical conductivity — 12 % IACS, worse than 78% of magnesium alloy grades
AM100A-T7 properties
Typical room-temperature values for AM100A-T7; 11 are specific to this condition. Other listed values are AM100A reference data and may not represent this condition. Bars are the position among magnesium alloy grades.
Physical3
AM100A-T7 has a density of 1.81 g/cm³ (0.0654 lb/in³), heavier than 58% of magnesium alloy grades. It melts at 465°C (869 °F).
Mechanical13
AM100A-T7 has a yield strength of 110 MPa (16 ksi) and a tensile strength of 250 MPa (36.3 ksi) — weaker than 83% of magnesium alloy grades. Elongation at break is 4% and the elastic modulus is 45 GPa (6.53 Msi).
Thermal6
AM100A-T7 is rated for continuous service to 150°C (302 °F). It conducts heat at 72 W/m·K (41.6 BTU/hr·ft·°F), worse than 69% of magnesium alloy grades. Thermal expansion is 25.2 µm/m·K (14 µin/in·°F).
Electrical3
AM100A-T7 conducts electricity at 12 % IACS, worse than 78% of magnesium alloy grades.
Chemical & Environmental3
Corrosion resistance is poor (21/100), worse than 68% of magnesium alloy grades.
Sustainability4
Producing a kilogram of AM100A-T7 takes about 320 MJ of energy and emits 30 kg of CO₂ — less than 74% of magnesium alloy grades. Typical recycled content is 25%.
Manufacturability8
AM100A-T7's machinability is excellent (95/100, better than 54% of magnesium alloy grades); weldability good (62/100); formability not recommended (8/100).
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with AM100A-T7
Is AM100A easy to machine?
Machines faster and with lower cutting forces than any other structural metal — use sharp tools, high speed, dry or mineral-oil cutting fluid (never water-based), and keep fine chips/dust collected wet or inert to avoid fire.
Can AM100A be welded?
GTAW/GMAW with AZ92A or AZ101A filler works well in the F condition; preheat thick sections, avoid mixing with steel spatter, and re-solution/re-age after welding T6 parts to restore properties.
Can AM100A be formed, bent or molded?
A casting alloy only — good sand and permanent-mold fluidity with SF6-free cover-gas or flux melting; not cold formable, so shape must come from the mold.
What surface finishes work on AM100A?
Always clean/pickle then apply a chromate or chrome-free conversion coat, Dow 17/HAE anodize or PEO before primer and paint; isolate all steel, brass and aluminium fasteners to prevent galvanic attack.
AM100A 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 |
|---|---|---|
| Alprincipal strengthening/ageing element (Mg17Al12) | 9.3 – 10.7 | 10 |
| Mn0.10 % min; controls Fe for corrosion | 0.1 – 0.35 | 0.15 |
| Zn | ≤ 0.3 | 0.1 |
| Si | ≤ 0.3 | — |
| Cuimpurity limit | ≤ 0.1 | — |
| Niimpurity limit | ≤ 0.01 | — |
| Fetypical high-purity practice limit; older specs control Fe via Fe/Mn ratio | ≤ 0.01 | — |
| Other (each/total)others total | ≤ 0.3 | — |
| Mg | balance | — |
AM100A-T7 — frequently asked
What is AM100A-T7 used for?
AM100A-T7 is typically used for engine covers, gearbox housings and brackets. In short: superseded by AZ91; very low cast ductility; excellent machinability, poor corrosion.
What is the yield strength of AM100A-T7?
AM100A-T7 has a typical yield strength of 110 MPa (16 ksi) and a tensile strength of 250 MPa (36.3 ksi) — weaker than 83% of magnesium alloy grades. Strength varies by condition: see the 5 listed tempers.
Is AM100A-T7 easy to machine?
Yes — machinability is rated excellent (95/100, better than 54% of magnesium alloy grades). Machines faster and with lower cutting forces than any other structural metal — use sharp tools, high speed, dry or mineral-oil cutting fluid (never water-based), and keep fine chips/dust collected wet or inert to avoid fire.
Can AM100A-T7 be welded?
Yes — weldability is rated good (62/100). GTAW/GMAW with AZ92A or AZ101A filler works well in the F condition; preheat thick sections, avoid mixing with steel spatter, and re-solution/re-age after welding T6 parts to restore properties.
What surface finishes work on AM100A-T7?
Always clean/pickle then apply a chromate or chrome-free conversion coat, Dow 17/HAE anodize or PEO before primer and paint; isolate all steel, brass and aluminium fasteners to prevent galvanic attack.
Can AM100A-T7 be formed, bent or molded?
A casting alloy only — good sand and permanent-mold fluidity with SF6-free cover-gas or flux melting; not cold formable, so shape must come from the mold.
What is the maximum service temperature of AM100A-T7?
AM100A-T7 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 AM100A-T6 and AM100A-F?
T6 is the default condition — standard supply condition: highest yield strength and hardness, accepted at the cost of very low elongation. F: lowest-cost condition for lightly loaded, dimensionally stable castings where no heat treatment is justified. Yield strength is 152 MPa in T6 versus 83 MPa in F.
Sources
- ASTM B199 — Magnesium-Alloy Permanent Mold Castings — ASTM International (2019)
- ASTM B80 — Magnesium-Alloy Sand Castings — ASTM International (2015)
- ASTM B93/B93M — Magnesium Alloys in Ingot Form for Sand, Permanent Mold and Die Castings — ASTM International (2020)
- ASM Specialty Handbook: Magnesium and Magnesium Alloys — ASM International (1999)
- ASM Handbook Vol.2 — Properties and Selection: Nonferrous Alloys — ASM International (1990)
- SAE AMS 4455 / UNS M10100 designation records — SAE International (2018)
Property data is compiled from published supplier and standards handbooks and normalised for comparison. Nothing on this page is a certification — request mill certs, CoC or material test reports with your order.