Aluminum ZL108
GB ZL108 · JIS AC8A
ZL108 is a eutectic Al-Si-Cu-Mg casting alloy (GB/T 1173 family, also listed as AC8A) with 1–2 % Cu plus Mg for heat-treatable strength, low thermal expansion and abrasive eutectic silicon for wear resistance; it cross-references closely to 336.0.
Reference datasheet — ZL108 is not in the instant-quote catalog. Upload your part and an engineer will quote it in this grade or suggest the closest stocked equivalent.
Values for the T6 condition
ZL108 tempers and conditions
ZL108 is supplied in 5 conditions, soft to hard. T6 is the default FabDigit quotes; the values on this page are for it.
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 |
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?
ZL108 is a eutectic Al-Si-Cu-Mg casting alloy (GB/T 1173 family, also listed as AC8A) with 1–2 % Cu plus Mg for heat-treatable strength, low thermal expansion and abrasive eutectic silicon for wear resistance; it cross-references closely to 336.0. It is specified for gravity die-cast pistons and similar parts that need dimensional stability up to 250 °C together with 121 W/m·K thermal conductivity. Elongation is only 0.7 %, machinability rates 38 and corrosion resistance 42, so PCD tooling and protective coatings are normal; nickel-bearing ZL109 is the usual step up for higher hot strength. ZL108 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). ZL108 has a yield strength of 230 MPa (33.4 ksi) and a tensile strength of 265 MPa (38.4 ksi) — stronger than 60% of aluminum grades. Elongation at break is 0.7% and the elastic modulus is 79 GPa (11.5 Msi).
What is ZL108 used for?
- Gasoline engine pistons
- Diesel engine piston blanks
- Reciprocating compressor pistons
- Air-conditioning compressor pistons
- Piston crowns and ring-belt sections
- Wear-resistant cast bushings and guides
Advantages
- High service temperature — 250°C (482 °F), better than 97% of aluminum grades
Limitations
- Limited ductility — 0.7%, worse than 98% of aluminum grades
- Limited formability — 5/100, worse than 94% of aluminum grades
- Low fracture toughness — 15 MPa·√m (13.7 ksi·√in), worse than 93% of aluminum grades
- Hard to polish — 40/100, worse than 91% of aluminum grades
- Low electrical conductivity — 27 % IACS, worse than 86% of aluminum grades
ZL108 properties
Typical room-temperature values for ZL108-T6; bars are the position among aluminum grades.
Physical3
ZL108 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 has a yield strength of 230 MPa (33.4 ksi) and a tensile strength of 265 MPa (38.4 ksi) — stronger than 60% of aluminum grades. Elongation at break is 0.7% and the elastic modulus is 79 GPa (11.5 Msi).
Thermal6
ZL108 is rated for continuous service to 250°C (482 °F). It conducts heat at 121 W/m·K (69.9 BTU/hr·ft·°F), worse than 76% of aluminum grades. Thermal expansion is 19.5 µm/m·K (10.8 µin/in·°F).
Electrical3
ZL108 conducts electricity at 27 % IACS, worse than 86% of aluminum grades.
Chemical & Environmental3
Corrosion resistance is fair (42/100), worse than 69% of aluminum grades.
Sustainability4
Producing a kilogram of ZL108 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's machinability is fair (38/100, worse than 84% of aluminum grades); weldability fair (40/100); formability not recommended (5/100).
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 aluminum family
Yield strength against density for every aluminum grade FabDigit runs. ZL108 is highlighted; hover a dot for its name, or open the interactive family chart.
Working with ZL108
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.
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 |
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.
Surface treatments FabDigit runs on aluminum 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).
Organic Coating
Equivalent designations
Standards and trade names that resolve to Aluminum ZL108 in FabDigit's catalog. Equivalence is nominal — check the exact specification when certification matters.
How much does ZL108 cost?
ZL108 is a standard-cost aluminum ($$), cheaper than about 71% 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.
ZL108 — frequently asked
What is ZL108 used for?
ZL108 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?
ZL108 has a typical yield strength of 230 MPa (33.4 ksi) and a tensile strength of 265 MPa (38.4 ksi) — stronger than 60% of aluminum grades. Strength varies by condition: see the 5 listed tempers.
Is ZL108 easy to machine?
Not especially — machinability is rated fair (38/100, 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 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?
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 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?
ZL108 is rated for continuous use to about 250°C (482 °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.
How much does ZL108 cost?
ZL108 is a standard-cost aluminum ($$), cheaper than about 71% 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.
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; 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.