Magnesium Alloy ML5-T6
Temper
T6 = solution heat treated and artificially aged
Pick when maximum yield strength, hardness and dimensional stability matter more than ductility.
Values for the T6 condition
Other ML5 tempers and conditions
ML5 is listed in 5 conditions; see the grade overview at ML5.
Compare all 5 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
Cooled from hot working, cold worked and naturally aged | Use when residual stress from casting, welding or heavy machining must be removed and strength is secondary. | 85 | 160 | 3 | 52 HB | 13 % IACS |
T4Default Solution heat treated and naturally aged | Standard aerospace condition for ML5 castings — best combination of strength, ductility and impact resistance. | 95 | 260 | 8 | 60 HB | 72 W/m·K |
As fabricated | Lowest cost condition for lightly loaded housings and covers where ductility is not critical. | 95 | 165 | 2.5 | 55 HB | 72 W/m·K |
Cooled from hot working and naturally aged | Simple ageing of the as-cast part to raise yield strength and stabilise dimensions without a solution treatment. | 110 | 195 | 2 | 65 HB | 12.5 % IACS |
T6This page Solution heat treated and artificially aged | Pick when maximum yield strength, hardness and dimensional stability matter more than ductility. | 135 | 275 | 4 | 70 HB | 72 W/m·K |
What is ML5-T6?
ML5-T6 is ML5 in the T6 temper — pick when maximum yield strength, hardness and dimensional stability matter more than ductility. ML5-T6 has a yield strength of 135 MPa (19.6 ksi) and a tensile strength of 275 MPa (39.9 ksi) — weaker than 67% of magnesium alloy grades. Elongation at break is 4% and the elastic modulus is 45 GPa (6.53 Msi). ML5-T6 has a density of 1.81 g/cm³ (0.0654 lb/in³), heavier than 58% of magnesium alloy grades. It melts at 470°C (878 °F). T4 is the default condition FabDigit quotes; T6 is available on request or by drawing note.
Limitations
- Low fracture toughness — 12 MPa·√m (10.9 ksi·√in), worse than 92% of magnesium alloy grades
- Low electrical conductivity — 12 % IACS, worse than 78% of magnesium alloy grades
ML5-T6 properties
Typical room-temperature values for ML5-T6; 12 are specific to this condition. Other listed values are ML5 reference data and may not represent this condition. Bars are the position among magnesium alloy grades.
Physical3
ML5-T6 has a density of 1.81 g/cm³ (0.0654 lb/in³), heavier than 58% of magnesium alloy grades. It melts at 470°C (878 °F).
Mechanical13
ML5-T6 has a yield strength of 135 MPa (19.6 ksi) and a tensile strength of 275 MPa (39.9 ksi) — weaker than 67% of magnesium alloy grades. Elongation at break is 4% and the elastic modulus is 45 GPa (6.53 Msi).
Thermal6
ML5-T6 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 26 µm/m·K (14.4 µin/in·°F).
Electrical3
ML5-T6 conducts electricity at 12 % IACS, worse than 78% of magnesium alloy grades.
Chemical & Environmental3
Corrosion resistance is poor (20/100), worse than 77% of magnesium alloy grades.
Sustainability4
Producing a kilogram of ML5-T6 takes about 320 MJ of energy and emits 30 kg of CO₂ — less than 74% of magnesium alloy grades. Typical recycled content is 30%.
Manufacturability8
ML5-T6's machinability is excellent (96/100, better than 87% of magnesium alloy grades); weldability good (65/100); formability poor (15/100).
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with ML5-T6
Is ML5 easy to machine?
Outstanding machinability with sharp, high-rake tooling and high speeds; use dry or mineral-oil cutting (never water-based) and manage fine chips against fire risk.
Can ML5 be welded?
Readily GTAW/GMAW welded with AZ92A or AZ101 filler in argon; preheat thick sections and stress-relieve or re-solution treat after welding.
Can ML5 be formed, bent or molded?
Sand and permanent-mould casting alloy with good fluidity and low hot-tearing tendency; melt must be flux- or SF6/SO2-protected and grain refined by superheat.
What surface finishes work on ML5?
No conventional anodizing — use chromate/Dow 17/HAE conversion coatings or plasma-electrolytic oxidation, then epoxy primer and paint; isolate from steel and aluminium fasteners to avoid galvanic attack.
ML5 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 |
|---|---|---|
| Alprimary strengthening element (Mg17Al12) | 7.5 – 9 | 8.3 |
| Zn | 0.2 – 0.8 | 0.5 |
| Mncontrols Fe for corrosion resistance | 0.15 – 0.5 | 0.3 |
| Siimpurity | ≤ 0.25 | — |
| Cuimpurity | ≤ 0.1 | — |
| Feimpurity | ≤ 0.06 | — |
| Niimpurity, strongly harmful to corrosion | ≤ 0.01 | — |
| Bemelt oxidation inhibitor | ≤ 0 | — |
| Mg | balance | — |
ML5-T6 — frequently asked
What is ML5-T6 used for?
ML5-T6 is typically used for gearbox housings, aircraft fitting castings and machinery housings. In short: best-machining cast magnesium; weldable AZ91C-type casting; heat-treatable to T6.
What is the yield strength of ML5-T6?
ML5-T6 has a typical yield strength of 135 MPa (19.6 ksi) and a tensile strength of 275 MPa (39.9 ksi) — weaker than 67% of magnesium alloy grades. Strength varies by condition: see the 5 listed tempers.
Is ML5-T6 easy to machine?
Yes — machinability is rated excellent (96/100, better than 87% of magnesium alloy grades). Outstanding machinability with sharp, high-rake tooling and high speeds; use dry or mineral-oil cutting (never water-based) and manage fine chips against fire risk.
Can ML5-T6 be welded?
Yes — weldability is rated good (65/100). Readily GTAW/GMAW welded with AZ92A or AZ101 filler in argon; preheat thick sections and stress-relieve or re-solution treat after welding.
What surface finishes work on ML5-T6?
No conventional anodizing — use chromate/Dow 17/HAE conversion coatings or plasma-electrolytic oxidation, then epoxy primer and paint; isolate from steel and aluminium fasteners to avoid galvanic attack.
Can ML5-T6 be formed, bent or molded?
Sand and permanent-mould casting alloy with good fluidity and low hot-tearing tendency; melt must be flux- or SF6/SO2-protected and grain refined by superheat.
What is the maximum service temperature of ML5-T6?
ML5-T6 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 ML5-T4 and ML5-T6?
T4 is the default condition — standard aerospace condition for ML5 castings — best combination of strength, ductility and impact resistance. T6: pick when maximum yield strength, hardness and dimensional stability matter more than ductility. Yield strength is 95 MPa in T4 versus 135 MPa in T6.
Sources
- GOST 2856-79 Magnesium casting alloys — grades — Gosstandart (1979)
- ASTM B80 / ASTM B403 Magnesium-Alloy Sand and Investment Castings (AZ91C/AZ91E) — ASTM International (2020)
- ASM Handbook Vol. 2 — Properties and Selection: Nonferrous Alloys — ASM International (1990)
- ASM Specialty Handbook: Magnesium and Magnesium Alloys — ASM International (1999)
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.