Aluminum 771.0
AA 771.0 · UNS A07710 · also 71A
771.0 (A07710, 71A) is a heat-treatable high-strength Al-Zn-Mg sand and permanent-mold casting alloy, available in F, T2, T5, T51, T52, T53, T6 and T71.
Reference datasheet — 771.0 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 T71 condition
771.0 tempers and conditions
771.0 is supplied in 8 conditions, soft to hard. T71 is the default FabDigit quotes; the values on this page are for it.
Compare all 8 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
As fabricated | As-poured condition; used only as the starting point for aging or where strength is not critical. | 125 | 200 | 3 | 60 HB | 32 % IACS |
Cooled from hot working, cold worked and naturally aged | Choose when dimensional stability and machining freedom matter more than strength. | 150 | 220 | 2 | 70 HB | 38 % IACS |
T5, stress relieved by stretching | Mild age used mainly to relieve casting stress and stabilize dimensions with modest strengthening. | 186 | 220 | 3 | 70 HB | 36 % IACS |
T5, stress relieved by compression | Best compromise of dimensional stability and moderate strength for machined housings and fixtures. | 207 | 248 | 1.5 | 70 HB | 36 % IACS |
As-cast plus modified stabilizing/aging cycle | Registered variant of the T52 cycle giving similar strength with tighter dimensional control. | 207 | 248 | 1.5 | 70 HB | 36 % IACS |
Solution heat treated and artificially aged | Full heat treatment for the best strength–ductility balance when quench distortion can be tolerated. | 241 | 290 | 5 | 75 HB | 32 % IACS |
Cooled from hot working and artificially aged | Highest strength without any solution treatment/quench — the classic low-distortion route for complex castings. | 262 | 290 | 1.5 | 85 HB | 34 % IACS |
T71Default Solution heat treated and overaged | Highest-strength, most dimensionally stable and most SCC-resistant temper — the usual production condition for 771.0 castings. | 310 | 330 | 2 | 90 HB | 35 % IACS |
What is 771.0?
771.0 (A07710, 71A) is a heat-treatable high-strength Al-Zn-Mg sand and permanent-mold casting alloy, available in F, T2, T5, T51, T52, T53, T6 and T71. It is used where strength-to-weight ratio drives the design, reaching 310 MPa yield, 330 MPa tensile, 90 HB and 35% IACS with a machinability score of 80. Elongation is only 2%, corrosion resistance scores 55 with stress-corrosion sensitivity in the Al-Zn-Mg matrix, hot-tear sensitivity is high and service is limited to 150 °C. 707.0 is the lower-strength alternative in the same system. 771.0 has a density of 2.81 g/cm³ (0.102 lb/in³), heavier than 86% of aluminum grades. It melts at 604°C (1,119 °F). 771.0 has a yield strength of 310 MPa (45 ksi) and a tensile strength of 330 MPa (47.9 ksi) — stronger than 78% of aluminum grades. Elongation at break is 2% and the elastic modulus is 71 GPa (10.3 Msi).
What is 771.0 used for?
- aircraft castings
- instrument housings
- structural parts
Advantages
- Easy to machine — 80/100, better than 92% of aluminum grades
- Polishes to a fine finish — 70/100, better than 87% of aluminum grades
- High strength — 310 MPa (45 ksi), better than 78% of aluminum grades
Limitations
- Limited ductility — 2%, worse than 87% of aluminum grades
- Limited formability — 10/100, worse than 80% of aluminum grades
771.0 properties
Typical room-temperature values for 771.0-T71; bars are the position among aluminum grades.
Physical3
771.0 has a density of 2.81 g/cm³ (0.102 lb/in³), heavier than 86% of aluminum grades. It melts at 604°C (1,119 °F).
Mechanical10
771.0 has a yield strength of 310 MPa (45 ksi) and a tensile strength of 330 MPa (47.9 ksi) — stronger than 78% of aluminum grades. Elongation at break is 2% and the elastic modulus is 71 GPa (10.3 Msi).
Thermal6
771.0 is rated for continuous service to 150°C (302 °F). It conducts heat at 130 W/m·K (75.1 BTU/hr·ft·°F), worse than 65% of aluminum grades. Thermal expansion is 24 µm/m·K (13.3 µin/in·°F).
Electrical3
771.0 conducts electricity at 35 % IACS, better than 52% of aluminum grades.
Chemical & Environmental3
Corrosion resistance is good (55/100), worse than 51% of aluminum grades.
Sustainability4
Producing a kilogram of 771.0 takes about 200 MJ of energy and emits 12.5 kg of CO₂ — less than 60% of aluminum grades. Typical recycled content is 25%.
Manufacturability8
771.0's machinability is very good (80/100, better than 92% of aluminum grades); weldability fair (45/100); formability not recommended (10/100).
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. 771.0 is highlighted; hover a dot for its name, or open the interactive family chart.
Working with 771.0
Is 771.0 easy to machine?
Excellent — machines to a bright, burr-free finish with polished-flute carbide, high speed and low feed pressure; T5/T71 chip better than as-cast F.
Can 771.0 be welded?
GTAW/GMAW possible with 5356 or 4043 filler, but the Al-Zn-Mg matrix is hot-crack and SCC sensitive; re-age after welding and avoid weld repairs in stressed areas.
Can 771.0 be formed, bent or molded?
Sand and permanent-mold casting only; fluidity is moderate and hot-tear sensitivity high, so use generous fillets, chills and well-fed risering; the alloy self-ages so many parts skip solution treatment.
771.0 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 |
|---|---|---|
| Si | ≤ 0.15 | |
| Fe | ≤ 0.15 | |
| Cu | ≤ 0.1 | |
| Mn | ≤ 0.1 | |
| Mg | 0.8 – 1 | 0.9 |
| Cr | 0.06 – 0.2 | 0.13 |
| Zn | 6.5 – 7.5 | 7 |
| Tigrain refiner | 0.1 – 0.2 | 0.15 |
| Others (each) | ≤ 0.05 | |
| Others (total) | ≤ 0.15 | |
| Al | balance |
What surface finishes work on 771.0?
Takes clear and hard anodize well (slightly grey tone), accepts chromate/ trivalent conversion coating and paint; polish before anodizing for cosmetic parts.
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 771.0 in FabDigit's catalog. Equivalence is nominal — check the exact specification when certification matters.
- UNS
- A07710
- Trade names
- 71A
How much does 771.0 cost?
771.0 is a premium-cost aluminum ($$$), cheaper than about 51% 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.
771.0 — frequently asked
What is 771.0 used for?
771.0 is typically used for aircraft castings, instrument housings and structural parts. In short: strongest 7xx.x casting alloy; high strength-to-weight ratio; machines to bright finish.
What is the yield strength of 771.0?
771.0 has a typical yield strength of 310 MPa (45 ksi) and a tensile strength of 330 MPa (47.9 ksi) — stronger than 78% of aluminum grades. Strength varies by condition: see the 8 listed tempers.
Is 771.0 easy to machine?
Yes — machinability is rated very good (80/100, better than 92% of aluminum grades). Excellent — machines to a bright, burr-free finish with polished-flute carbide, high speed and low feed pressure; T5/T71 chip better than as-cast F.
Can 771.0 be welded?
With care — weldability is rated fair (45/100). GTAW/GMAW possible with 5356 or 4043 filler, but the Al-Zn-Mg matrix is hot-crack and SCC sensitive; re-age after welding and avoid weld repairs in stressed areas.
What surface finishes work on 771.0?
Takes clear and hard anodize well (slightly grey tone), accepts chromate/ trivalent conversion coating and paint; polish before anodizing for cosmetic parts.
Can 771.0 be formed, bent or molded?
Sand and permanent-mold casting only; fluidity is moderate and hot-tear sensitivity high, so use generous fillets, chills and well-fed risering; the alloy self-ages so many parts skip solution treatment.
What is the maximum service temperature of 771.0?
771.0 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 771.0-T71 and 771.0-F?
T71 is the default condition — highest-strength, most dimensionally stable and most SCC-resistant temper — the usual production condition for 771.0 castings. F: as-poured condition; used only as the starting point for aging or where strength is not critical. Yield strength is 310 MPa in T71 versus 125 MPa in F.
How much does 771.0 cost?
771.0 is a premium-cost aluminum ($$$), cheaper than about 51% 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
- ASTM B26/B26M — Aluminum-Alloy Sand Castings — ASTM International (2018)
- Registration Record of Aluminum Association Alloy Designations and Chemical Composition Limits for Aluminum Alloys in the Form of Castings and Ingot ('Pink Sheets') — The Aluminum Association (2018)
- ASM Specialty Handbook: Aluminum and Aluminum Alloys — ASM International (1993)
- ASM Handbook Vol. 2 — Properties and Selection: Nonferrous Alloys and Special-Purpose Materials — ASM International (1990)
- ASM Handbook Vol. 15 — Casting — ASM International (2008)
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.