Magnesium Alloy ZM5-T6
Temper
T6 = solution heat treated and artificially aged
Choose when maximum yield strength and hardness are needed and low elongation is acceptable.
Values for the T6 condition
Other ZM5 tempers and conditions
ZM5 is listed in 6 conditions; see the grade overview at ZM5.
Compare all 6 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
Cooled from hot working, cold worked and naturally aged | Low-temperature anneal used to relieve casting or machining stresses and stabilise dimensions before finish machining. | 85 | 160 | 3 | 52 HB | 13 % IACS |
T4Default Solution heat treated and naturally aged | Most-used ZM5 condition: best combination of strength, ductility and impact resistance for structural castings. | 90 | 250 | 8 | 55 HB | 11.5 % IACS |
As fabricated | Lowest-cost condition for lightly loaded housings and covers where dimensional stability matters more than strength. | 90 | 165 | 2.5 | 55 HB | 12 % IACS |
Cooled from hot working and naturally aged | Simple ageing (≈175 °C) of the as-cast part to raise yield strength and hardness without a solution treatment or distortion risk. | 110 | 180 | 2 | 62 HB | 13 % IACS |
T6This page Solution heat treated and artificially aged | Choose when maximum yield strength and hardness are needed and low elongation is acceptable. | 140 | 255 | 4 | 70 HB | 13.5 % IACS |
Die cast, as-cast | High-pressure die-cast ZM5/AZ91D: fine chill structure gives higher strength than sand casting, but heat treatment is limited by gas porosity. | 150 | 230 | 3 | 63 HB | 12 % IACS |
What is ZM5-T6?
ZM5-T6 is ZM5 in the T6 temper — choose when maximum yield strength and hardness are needed and low elongation is acceptable. ZM5-T6 has a yield strength of 140 MPa (20.3 ksi) and a tensile strength of 255 MPa (37 ksi) — weaker than 61% of magnesium alloy grades. Elongation at break is 4% and the elastic modulus is 45 GPa (6.53 Msi). ZM5-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
ZM5-T6 properties
Typical room-temperature values for ZM5-T6; 21 are specific to this condition. Other listed values are ZM5 reference data and may not represent this condition. Bars are the position among magnesium alloy grades.
Physical3
ZM5-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).
Mechanical15
ZM5-T6 has a yield strength of 140 MPa (20.3 ksi) and a tensile strength of 255 MPa (37 ksi) — weaker than 61% of magnesium alloy grades. Elongation at break is 4% and the elastic modulus is 45 GPa (6.53 Msi).
Thermal6
ZM5-T6 is rated for continuous service to 130°C (266 °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
ZM5-T6 conducts electricity at 13.5 % IACS, worse than 64% of magnesium alloy grades.
Chemical & Environmental3
Corrosion resistance is poor (20/100), worse than 77% of magnesium alloy grades.
Sustainability4
Producing a kilogram of ZM5-T6 takes about 330 MJ of energy and emits 30 kg of CO₂ — less than 56% of magnesium alloy grades. Typical recycled content is 30%.
Manufacturability8
ZM5-T6's machinability is excellent (95/100, better than 54% of magnesium alloy grades); weldability good (55/100); formability not recommended (12/100).
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with ZM5-T6
Is ZM5 easy to machine?
Cuts extremely easily with sharp positive-rake tools and high speeds; use dry or mineral-oil cutting (no water-based coolant) and control fine chips — magnesium swarf is a fire hazard.
Can ZM5 be welded?
GTAW/GMAW with AZ92A or AZ101 filler under argon works well; preheat thick sections, avoid welding heavily die-cast (gas-porous) parts, and stress relieve after welding.
Can ZM5 be formed, bent or molded?
A casting alloy — excellent fluidity and low hot-tearing tendency in sand, permanent-mould and high-pressure die casting; melt must be protected with SF6-free cover gas or flux.
What surface finishes work on ZM5?
Always apply chromate/phosphate conversion, Dow 17/HAE anodize or micro-arc oxidation plus paint; avoid direct contact with steel, copper or graphite to prevent galvanic corrosion.
ZM5 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 element (Mg17Al12) | 7.5 – 9 | 8.3 |
| Zn | 0.2 – 0.8 | 0.5 |
| Mnties up Fe, improves corrosion behaviour | 0.15 – 0.5 | 0.3 |
| Siimpurity limit | ≤ 0.3 | — |
| Cuimpurity limit; AZ91D high-purity variants ≤0.030 | ≤ 0.1 | — |
| FeAZ91D high-purity variants ≤0.005 | ≤ 0.05 | — |
| NiAZ91D high-purity variants ≤0.002 | ≤ 0.01 | — |
| Beoptional melt-protection addition | 1×10⁻⁴ – 0 | 8×10⁻⁴ |
| Others (total) | ≤ 0.5 | — |
| Mg | balance | — |
ZM5-T6 — frequently asked
What is ZM5-T6 used for?
ZM5-T6 is typically used for gearbox housings, engine covers, electronic enclosures and automotive brackets. In short: general-purpose AZ91 equivalent; best-casting magnesium alloy; weldable with AZ92A filler.
What is the yield strength of ZM5-T6?
ZM5-T6 has a typical yield strength of 140 MPa (20.3 ksi) and a tensile strength of 255 MPa (37 ksi) — weaker than 61% of magnesium alloy grades. Strength varies by condition: see the 6 listed tempers.
Is ZM5-T6 easy to machine?
Yes — machinability is rated excellent (95/100, better than 54% of magnesium alloy grades). Cuts extremely easily with sharp positive-rake tools and high speeds; use dry or mineral-oil cutting (no water-based coolant) and control fine chips — magnesium swarf is a fire hazard.
Can ZM5-T6 be welded?
Yes — weldability is rated good (55/100). GTAW/GMAW with AZ92A or AZ101 filler under argon works well; preheat thick sections, avoid welding heavily die-cast (gas-porous) parts, and stress relieve after welding.
What surface finishes work on ZM5-T6?
Always apply chromate/phosphate conversion, Dow 17/HAE anodize or micro-arc oxidation plus paint; avoid direct contact with steel, copper or graphite to prevent galvanic corrosion.
Can ZM5-T6 be formed, bent or molded?
A casting alloy — excellent fluidity and low hot-tearing tendency in sand, permanent-mould and high-pressure die casting; melt must be protected with SF6-free cover gas or flux.
What is the maximum service temperature of ZM5-T6?
ZM5-T6 is rated for continuous use to about 130°C (266 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
What is the difference between ZM5-T4 and ZM5 DC-F?
T4 is the default condition — most-used ZM5 condition: best combination of strength, ductility and impact resistance for structural castings. DC-F: high-pressure die-cast ZM5/AZ91D: fine chill structure gives higher strength than sand casting, but heat treatment is limited by gas porosity. Yield strength is 90 MPa in T4 versus 150 MPa in DC-F.
Sources
- GB/T 1177 (ZM5 / ZMgAl8Zn) — SAC / (2018)
- ASTM B80 / B94 (AZ91C, AZ91D magnesium castings) — ASTM International (2021)
- ASM Handbook Vol.2 — Properties and Selection: Nonferrous Alloys — ASM International (1990)
- ASM Specialty Handbook: Magnesium and Magnesium Alloys — ASM International (1999)
- ASM Handbook Vol.13B — Corrosion of Magnesium Alloys — ASM International (2005)
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.