Aluminum ZL108-T5
Temper
GB ZL108 · JIS AC8A
T5 = cooled from hot working and artificially aged
Short stabilising age used when quick throughput and stable dimensions matter more than peak strength.
Values for the T5 condition
Other ZL108 tempers and conditions
ZL108 is listed in 5 conditions; see the grade overview at ZL108.
Compare all 5 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
As fabricated | Pick for low-cost parts where dimensional stability at temperature and maximum strength are not required. | 130 | 175 | 1 | 80 HB | 30 % IACS |
T5This page Cooled from hot working and artificially aged | Short stabilising age used when quick throughput and stable dimensions matter more than peak strength. | 160 | 195 | 0.9 | 88 HB | 29 % IACS |
Cooled from hot working and naturally aged | Standard low-cost piston condition: aging only, good dimensional stability without the distortion risk of quenching. | 170 | 205 | 0.8 | 90 HB | 29 % IACS |
Solution heat treated and overaged (stabilized) | Overaged for maximum dimensional and structural stability in long-term hot service (250–300 °C), at some loss of room-temperature strength. | 185 | 225 | 1 | 95 HB | 30 % IACS |
T6Default Solution heat treated and artificially aged | Highest-strength, highest-hardness condition — the default choice for loaded pistons, compressor parts and wear surfaces. | 230 | 265 | 0.7 | 105 HB | 27 % IACS |
What is ZL108-T5?
ZL108-T5 is ZL108 in the T5 temper — short stabilising age used when quick throughput and stable dimensions matter more than peak strength. ZL108-T5 has a yield strength of 160 MPa (23.2 ksi) and a tensile strength of 195 MPa (28.3 ksi) — weaker than 61% of aluminum grades. Elongation at break is 0.9% and the elastic modulus is 79 GPa (11.5 Msi). ZL108-T5 has a density of 2.68 g/cm³ (0.0968 lb/in³), lighter than 72% of aluminum grades. It melts at 516°C (961 °F). T6 is the default condition FabDigit quotes; T5 is available on request or by drawing note.
Advantages
- High service temperature — 230°C (446 °F), better than 95% of aluminum grades
Limitations
- Limited formability — 4/100, worse than 99% of aluminum grades
- Low fracture toughness — 13 MPa·√m (11.8 ksi·√in), worse than 98% of aluminum grades
- Limited ductility — 0.9%, worse than 97% of aluminum grades
- Hard to polish — 40/100, worse than 91% of aluminum grades
- Difficult to machine — 37/100, worse than 84% of aluminum grades
ZL108-T5 properties
Typical room-temperature values for ZL108-T5; 22 are specific to this condition. Other listed values are ZL108 reference data and may not represent this condition. Bars are the position among aluminum grades.
Physical3
ZL108-T5 has a density of 2.68 g/cm³ (0.0968 lb/in³), lighter than 72% of aluminum grades. It melts at 516°C (961 °F).
Mechanical12
ZL108-T5 has a yield strength of 160 MPa (23.2 ksi) and a tensile strength of 195 MPa (28.3 ksi) — weaker than 61% of aluminum grades. Elongation at break is 0.9% and the elastic modulus is 79 GPa (11.5 Msi).
Thermal6
ZL108-T5 is rated for continuous service to 230°C (446 °F). It conducts heat at 132 W/m·K (76.3 BTU/hr·ft·°F), worse than 61% of aluminum grades. Thermal expansion is 19.5 µm/m·K (10.8 µin/in·°F).
Electrical3
ZL108-T5 conducts electricity at 29 % IACS, worse than 78% of aluminum grades.
Chemical & Environmental3
Corrosion resistance is fair (42/100), worse than 69% of aluminum grades.
Sustainability4
Producing a kilogram of ZL108-T5 takes about 200 MJ of energy and emits 12 kg of CO₂ — less than 60% of aluminum grades. Typical recycled content is 60%.
Manufacturability8
ZL108-T5's machinability is fair (37/100, worse than 84% of aluminum grades); weldability fair (40/100); formability not recommended (4/100).
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with ZL108-T5
Is ZL108 easy to machine?
Abrasive eutectic silicon demands PCD or diamond-coated carbide tooling, high speed/low feed and flood coolant; chips are short and finishing is good once tooling is right.
Can ZL108 be welded?
Repair-weldable by TIG with 4047/ZL102-type filler, but the 1–2 % Cu makes it hot-crack sensitive — preheat 150–200 °C and re-age after welding.
Can ZL108 be formed, bent or molded?
Gravity die (metal mould) casting is standard — excellent fluidity and low shrinkage; use P modification for the primary silicon, avoid Na, and feed heavy sections well since the alloy has essentially no cold formability.
What surface finishes work on ZL108?
Hard anodizing of crowns/ring grooves works well; decorative anodizing is dark and mottled, so paint, chemical conversion or Sn/graphite skirt coatings are the usual alternatives.
ZL108 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 |
|---|---|---|
| Sinear-eutectic; usually P-modified for primary Si refinement | 11 – 13 | 12 |
| Cu | 1 – 2 | 1.5 |
| Mg | 0.4 – 1 | 0.8 |
| Mn | 0.3 – 0.9 | 0.5 |
| Feimpurity limit, metal-mould castings | ≤ 0.8 | — |
| Znimpurity | ≤ 0.3 | — |
| Niimpurity | ≤ 0.3 | — |
| Tiimpurity / grain refiner residue | ≤ 0.2 | — |
| others (each)total ≤ 0.15 | ≤ 0.05 | — |
| Al | balance | — |
ZL108-T5 — frequently asked
What is ZL108-T5 used for?
ZL108-T5 is typically used for gasoline engine pistons, diesel engine piston blanks, reciprocating compressor pistons, air-conditioning compressor pistons, piston crowns and ring-belt sections and wear-resistant cast bushings and guides. In short: low-expansion piston alloy; wear-resistant eutectic Al-Si; stable to 250 °C.
What is the yield strength of ZL108-T5?
ZL108-T5 has a typical yield strength of 160 MPa (23.2 ksi) and a tensile strength of 195 MPa (28.3 ksi) — weaker than 61% of aluminum grades. Strength varies by condition: see the 5 listed tempers.
Is ZL108-T5 easy to machine?
Not especially — machinability is rated fair (37/100, worse than 84% of aluminum grades). Abrasive eutectic silicon demands PCD or diamond-coated carbide tooling, high speed/low feed and flood coolant; chips are short and finishing is good once tooling is right.
Can ZL108-T5 be welded?
With care — weldability is rated fair (40/100). Repair-weldable by TIG with 4047/ZL102-type filler, but the 1–2 % Cu makes it hot-crack sensitive — preheat 150–200 °C and re-age after welding.
What surface finishes work on ZL108-T5?
Hard anodizing of crowns/ring grooves works well; decorative anodizing is dark and mottled, so paint, chemical conversion or Sn/graphite skirt coatings are the usual alternatives.
Can ZL108-T5 be formed, bent or molded?
Gravity die (metal mould) casting is standard — excellent fluidity and low shrinkage; use P modification for the primary silicon, avoid Na, and feed heavy sections well since the alloy has essentially no cold formability.
What is the maximum service temperature of ZL108-T5?
ZL108-T5 is rated for continuous use to about 230°C (446 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
What is the difference between ZL108-T6 and ZL108-F?
T6 is the default condition — highest-strength, highest-hardness condition — the default choice for loaded pistons, compressor parts and wear surfaces. F: pick for low-cost parts where dimensional stability at temperature and maximum strength are not required. Yield strength is 230 MPa in T6 versus 130 MPa in F.
Sources
- GB/T 1173 (ZL108 / ZAlSi12Cu2Mg1) (2013)
- JIS H 5202 Aluminium alloy castings (AC8A) — JSA (2010)
- ASM Handbook Vol.2: Properties and Selection — Nonferrous Alloys (336.0) — ASM International (1990)
- ASM Specialty Handbook: Aluminum and Aluminum Alloys — ASM International (1993)
- Aluminum Association Pink Sheets — Designations and Chemical Composition Limits for Aluminum Alloys in the Form of Castings and Ingot — The Aluminum Association (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.