Aluminum Al2O3f/AC8A-F (As fabricated)
Temper
Pick for prototype pistons or where subsequent T5/T6 ageing is done downstream; lowest strength, highest residual stress.
Values for the F condition
Other Al2O3f/AC8A tempers and conditions
Al2O3f/AC8A is listed in 7 conditions; see the grade overview at Al2O3f/AC8A.
Compare all 7 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
FThis page As fabricated | Pick for prototype pistons or where subsequent T5/T6 ageing is done downstream; lowest strength, highest residual stress. | 150 | 195 | 0.9 | 95 HB | 27 % IACS |
Cooled from hot working and artificially aged | Low-distortion option for thin-wall pistons: modest strength gain without a solution quench. | 185 | 220 | 0.7 | 108 HB | 26 % IACS |
Solution heat treated and overaged (stabilized) | Choose when long-term dimensional stability and growth resistance at 300–350 °C matter more than peak strength. | 200 | 230 | 1 | 108 HB | 29 % IACS |
5 vol% Al2O3-SiO2 short fibre, T6 | Low fibre loading for easier infiltration and better thermal conduction where only moderate groove wear resistance is needed. | 215 | 255 | 1 | 115 HB | 27 % IACS |
T6Default Solution heat treated and artificially aged | Standard production condition for fibre-reinforced diesel pistons — highest room- and elevated-temperature strength and ring-groove wear resistance. | 230 | 260 | 0.6 | 125 HB | 24 % IACS |
12 vol% Al2O3-SiO2 short fibre, T6 | The classic Toyota ring-groove reinforcement level — best balance of wear resistance, thermal fatigue life and machinability. | 230 | 260 | 0.6 | 125 HB | 24 % IACS |
20 vol% Al2O3-SiO2 short fibre, T6 | Maximum stiffness and wear/creep resistance for high-BMEP diesel pistons; lowest ductility, hardest to infiltrate and machine. | — | 250 | 0.3 | 145 HB | 88 W/m·K |
What is Al2O3f/AC8A-F?
Al2O3f/AC8A-F is Al2O3f/AC8A in the F temper — pick for prototype pistons or where subsequent T5/T6 ageing is done downstream; lowest strength, highest residual stress. Al2O3f/AC8A-F has a yield strength of 150 MPa (21.8 ksi) and a tensile strength of 195 MPa (28.3 ksi) — weaker than 65% of aluminum grades. Elongation at break is 0.9% and the elastic modulus is 93 GPa (13.5 Msi). Al2O3f/AC8A-F has a density of 2.79 g/cm³ (0.101 lb/in³), heavier than 77% of aluminum grades. It melts at 520°C (968 °F). T6 is the default condition FabDigit quotes; F is available on request or by drawing note.
Advantages
- Stiff — 93 GPa (13.5 Msi), better than 99% of aluminum grades
- Low embodied carbon — 9 kg CO₂/kg, better than 99% of aluminum grades
- High service temperature — 250°C (482 °F), better than 97% of aluminum grades
Limitations
- Difficult to weld — 12/100, worse than 98% of aluminum grades
- Limited ductility — 0.9%, worse than 97% of aluminum grades
- Low fracture toughness — 14 MPa·√m (12.7 ksi·√in), worse than 97% of aluminum grades
- Difficult to machine — 25/100, worse than 96% of aluminum grades
- Limited formability — 5/100, worse than 94% of aluminum grades
Al2O3f/AC8A-F properties
Typical room-temperature values for Al2O3f/AC8A-F; 22 are specific to this condition. Other listed values are Al2O3f/AC8A reference data and may not represent this condition. Bars are the position among aluminum grades.
Physical3
Al2O3f/AC8A-F has a density of 2.79 g/cm³ (0.101 lb/in³), heavier than 77% of aluminum grades. It melts at 520°C (968 °F).
Mechanical16
Al2O3f/AC8A-F has a yield strength of 150 MPa (21.8 ksi) and a tensile strength of 195 MPa (28.3 ksi) — weaker than 65% of aluminum grades. Elongation at break is 0.9% and the elastic modulus is 93 GPa (13.5 Msi).
Thermal6
Al2O3f/AC8A-F is rated for continuous service to 250°C (482 °F). It conducts heat at 112 W/m·K (64.7 BTU/hr·ft·°F), worse than 86% of aluminum grades. Thermal expansion is 17.5 µm/m·K (9.72 µin/in·°F).
Electrical3
Al2O3f/AC8A-F conducts electricity at 27 % IACS, worse than 86% of aluminum grades.
Chemical & Environmental3
Corrosion resistance is fair (44/100), worse than 65% of aluminum grades.
Sustainability4
Producing a kilogram of Al2O3f/AC8A-F takes about 120 MJ of energy and emits 9 kg of CO₂ — less than 99% of aluminum grades. Typical recycled content is 25%.
Manufacturability8
Al2O3f/AC8A-F's machinability is poor (25/100, worse than 96% of aluminum grades); weldability not recommended (12/100); formability not recommended (5/100).
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with Al2O3f/AC8A-F
Is Al2O3f/AC8A easy to machine?
Turn/bore the ring-groove zone with PCD or fine-grain diamond-coated tooling at moderate speed and light feed; carbide wears out in minutes against the alumina fibres, and grinding is preferred for finishing.
Can Al2O3f/AC8A be welded?
Not fusion weldable — arc heat collapses fibre distribution and forms brittle interface phases; use mechanical joining or friction/solid-state processes only, and repair by re-casting is not practical.
Can Al2O3f/AC8A be formed, bent or molded?
Made only by squeeze casting / pressure infiltration of a fibre preform (typically 70–100 MPa, preform preheat ~700–800 °C, die ~250–350 °C); no wrought forming afterwards.
What surface finishes work on Al2O3f/AC8A?
Ring grooves are ground or PCD-finished; hard anodizing over the reinforced band is uneven, so tin plating, graphite skirt coating or thermal-barrier crown coatings are used instead.
Al2O3f/AC8A 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 |
|---|---|---|
| SiJIS H5202 AC8A matrix | 11 – 13 | 12 |
| Cu | 0.8 – 1.3 | 1 |
| Mg | 0.7 – 1.3 | 1 |
| Nihigh-temperature strength | 0.8 – 1.5 | 1.1 |
| Feimpurity limit | ≤ 0.8 | 0.4 |
| Mn | ≤ 0.15 | 0.05 |
| Zn | ≤ 0.15 | 0.05 |
| Tigrain refiner | ≤ 0.2 | 0.1 |
| Cr | ≤ 0.1 | — |
| Sn | ≤ 0.1 | — |
| Pb | ≤ 0.1 | — |
| Al2O3-SiO2 short fibre (Saffil type, ~96vol %, local preform in ring-groove zone only | 5 – 20 | 12 |
| Almatrix balance | balance | — |
Al2O3f/AC8A-F — frequently asked
What is Al2O3f/AC8A-F used for?
Al2O3f/AC8A-F is typically used for diesel engine pistons, ring-groove reinforcement inserts and high-temperature wear zones. In short: locally reinforced piston alloy; 350 °C ring-groove wear zone; ring-carrier replacement.
What is the yield strength of Al2O3f/AC8A-F?
Al2O3f/AC8A-F has a typical yield strength of 150 MPa (21.8 ksi) and a tensile strength of 195 MPa (28.3 ksi) — weaker than 65% of aluminum grades. Strength varies by condition: see the 7 listed tempers.
Is Al2O3f/AC8A-F easy to machine?
Not especially — machinability is rated poor (25/100, worse than 96% of aluminum grades). Turn/bore the ring-groove zone with PCD or fine-grain diamond-coated tooling at moderate speed and light feed; carbide wears out in minutes against the alumina fibres, and grinding is preferred for finishing.
Can Al2O3f/AC8A-F be welded?
Not readily — weldability is rated not recommended (12/100). Not fusion weldable — arc heat collapses fibre distribution and forms brittle interface phases; use mechanical joining or friction/solid-state processes only, and repair by re-casting is not practical.
What surface finishes work on Al2O3f/AC8A-F?
Ring grooves are ground or PCD-finished; hard anodizing over the reinforced band is uneven, so tin plating, graphite skirt coating or thermal-barrier crown coatings are used instead.
Can Al2O3f/AC8A-F be formed, bent or molded?
Made only by squeeze casting / pressure infiltration of a fibre preform (typically 70–100 MPa, preform preheat ~700–800 °C, die ~250–350 °C); no wrought forming afterwards.
What is the maximum service temperature of Al2O3f/AC8A-F?
Al2O3f/AC8A-F 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 Al2O3f/AC8A-T6 and Al2O3f/AC8A-F?
T6 is the default condition — standard production condition for fibre-reinforced diesel pistons — highest room- and elevated-temperature strength and ring-groove wear resistance. F: pick for prototype pistons or where subsequent T5/T6 ageing is done downstream; lowest strength, highest residual stress. Yield strength is 230 MPa in T6 versus 150 MPa in F.
Sources
- JIS H5202 — Aluminium alloy castings (AC8A) — JSA (2010)
- ASM Handbook Vol.21 — Composites (discontinuously reinforced aluminium) — ASM International (2001)
- ASM Handbook Vol.2 — Properties and Selection: Nonferrous Alloys — ASM International (1990)
- SAE 830252 — Ceramic fiber reinforced piston for high performance diesel engines — SAE International (1983)
- Saffil alumina short fibre (RF/LD grades) technical data — Saffil Ltd / Unifrax (2015)
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.