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Aluminum 7085 · temper

Aluminum 7085-T7651X

Properties of the T7651X condition, compared with the other 7085 tempers.

Extrusion condition for 7085 stringers/stiffeners needing high compressive yield plus exfoliation resistance.

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What is 7085-T7651X?

7085-T7651X is 7085 in the T7651X temper — extrusion condition for 7085 stringers/stiffeners needing high compressive yield plus exfoliation resistance. 7085-T7651X has a yield strength of 517 MPa (75 ksi) and a tensile strength of 545 MPa (79 ksi) — stronger than 97% of aluminum grades. Elongation at break is 9% and the elastic modulus is 70.5 GPa (10.2 Msi). 7085-T7651X has a density of 2.85 g/cm³ (0.103 lb/in³), heavier than 95% of aluminum grades. It melts at 477°C (891 °F). T7451 is the default condition FabDigit quotes; T7651X is available on request or by drawing note.

Advantages

  • High strength — 517 MPa (75 ksi), better than 97% of aluminum grades
  • Tough — resists crack growth — 32 MPa·√m (29.1 ksi·√in), better than 83% of aluminum grades
  • Easy to machine — 72/100, better than 80% of aluminum grades

Limitations

  • Difficult to weld — 20/100, worse than 89% of aluminum grades
  • Limited service temperature — 120°C (248 °F), worse than 79% of aluminum grades

7085-T7651X properties

Typical room-temperature values for 7085-T7651X — 9 properties are specific to this condition; the rest are grade-level values shared by every 7085 temper. Each bar shows where the value sits among the aluminum grades in FabDigit's library — further right is higher.

Physical3

7085-T7651X has a density of 2.85 g/cm³ (0.103 lb/in³), heavier than 95% of aluminum grades. It melts at 477°C (891 °F).

Density2.85 g/cm³0.1 lb/in³
Melting Point (Solidus)477°C891 °F
Liquidus Temperature635°C1,175 °F

Mechanical13

7085-T7651X has a yield strength of 517 MPa (75 ksi) and a tensile strength of 545 MPa (79 ksi) — stronger than 97% of aluminum grades. Elongation at break is 9% and the elastic modulus is 70.5 GPa (10.2 Msi).

Elastic (Young's) Modulus70.5 GPa10.2 Msi
Shear Modulus26.9 GPa3.9 Msi
Bulk Modulus70 GPa10.2 Msi
Poisson's Ratio0.33
Tensile Strength (Ultimate)545 MPa79 ksi
Yield Strength (0.2% offset)517 MPa75 ksi
Elongation at Break9%
Reduction in Area22%
Compressive Strength524 MPa76 ksi
Shear Strength300 MPa43.5 ksi
Fatigue Strength (Endurance Limit)155 MPa22.5 ksi
Fracture Toughness (K_IC)32 MPa·√m29.1 ksi·√in
Hardness, Brinell160 HB

Thermal6

7085-T7651X is rated for continuous service to 120°C (248 °F). It conducts heat at 152 W/m·K (87.8 BTU/hr·ft·°F), better than 66% of aluminum grades. Thermal expansion is 23.4 µm/m·K (13 µin/in·°F).

Thermal Conductivity152 W/m·K87.8 BTU/hr·ft·°F
Specific Heat Capacity860 J/kg·K0.21 BTU/lb·°F
Thermal Expansion (CTE, 20–100 °C)23.4 µm/m·K13 µin/in·°F
Latent Heat of Fusion390 J/g168 BTU/lb
Max Service Temperature (continuous)120°C248 °F
Min Service Temperature-196°C-321 °F

Electrical3

7085-T7651X conducts electricity at 39 % IACS, better than 65% of aluminum grades.

Electrical Conductivity39 % IACS
Electrical Resistivity4.2×10⁻⁸ Ω·m1.65 µΩ·in
Magnetic Responsenon-magnetic

Chemical & Environmental3

Corrosion resistance is fair (45/100), worse than 62% of aluminum grades.

Galvanic Potential (seawater, vs SCE)-0.84 V
Corrosion ResistanceFair45/100
Chemical Resistance SummaryGood in neutral atmospheres and dry environments; overaged T7x tempers give good resistance to exfoliation and stress-corrosion cracking. Attacked by strong alkalis and strong mineral acids, and vulnerable to pitting/galvanic attack in chloride media or when coupled to steel/CFRP — protect with anodize, clad layer or primer.

Sustainability4

Producing a kilogram of 7085-T7651X takes about 205 MJ of energy and emits 12.5 kg of CO₂ — more than 75% of aluminum grades. Typical recycled content is 8%.

Embodied Energy (primary production)205 MJ/kg88,134 BTU/lb
Embodied Carbon (primary production)12.5 kg CO₂/kg
Embodied Water1,200 L/kg144 gal/lb
Typical Recycled Content8%

Manufacturability8

7085-T7651X's machinability is very good (72/100, better than 80% of aluminum grades); weldability poor (20/100); formability poor (25/100).

MachinabilityVery good72/100
Machinability Rating (AISI 1212 = 100 %)70%
WeldabilityPoor20/100
Formability (cold)Poor25/100
CastabilityFair35/100
Brazeability / SolderabilityNot recommended10/100
PolishabilityGood60/100
Anodizing Responsegood — accepts sulfuric (Type II) and hard (Type III) anodize; high Zn/Cu gives a grey-to-bronze tint, so decorative colour matching is poor. Chromic/boric-sulfuric anodize used for aerospace corrosion protection.

Values are nominal handbook figures for design screening. Certified mill or lot data ships with every FabDigit order on request.

Other 7085 tempers and conditions

7085 is also supplied in 5 other conditions. The full side-by-side table is on the 7085 overview.

Working with 7085-T7651X

Is 7085 easy to machine?

Machines very freely in T74/T76 tempers with sharp polished carbide, high speed and flood coolant; large stock removal from thick plate needs symmetric passes and stress-relieved (T7x51/T7x52) material to control distortion.

Can 7085 be welded?

Not fusion weldable (hot cracking, drastic HAZ property loss) — join by riveting, bolting or friction stir welding with post-weld property allowance.

Can 7085 be formed, bent or molded?

Formed hot as thick plate or die forging; in the aged temper only mild bending/straightening is possible — do stretch/compression stress relief before machining.

What surface finishes work on 7085?

Chromic or boric-sulfuric anodize plus epoxy primer for aerospace corrosion protection; hard anodize possible but grey-tinted, and shot peening or Alclad/paint systems are used on exposed surfaces.

7085 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.

ElementSpec limit (wt %)Nominal
Si≤ 0.060.03
Femax — kept very low for toughness≤ 0.080.05
Cu1.3 – 21.6
Mn≤ 0.040.01
Mg1.2 – 1.81.5
Cr≤ 0.040.01
Zn7 – 87.5
Ti≤ 0.060.03
Zrdispersoid former, replaces Cr/Mn0.08 – 0.150.11
Others (each)≤ 0.05—
Others (total)≤ 0.15—
Albalance—

7085-T7651X — frequently asked

What is 7085-T7651X used for?

7085-T7651X is typically used for aerospace heavy forgings, wing spars, fuselage and wing bulkheads, machined wing ribs and frames, landing gear structural fittings and thick-plate airframe fittings. In short: ultra-thick aerospace forging; low quench sensitivity.

What is the yield strength of 7085-T7651X?

7085-T7651X has a typical yield strength of 517 MPa (75 ksi) and a tensile strength of 545 MPa (79 ksi) — stronger than 97% of aluminum grades. Strength varies by condition: see the 6 listed tempers.

Is 7085-T7651X easy to machine?

Yes — machinability is rated very good (72/100, better than 80% of aluminum grades). Machines very freely in T74/T76 tempers with sharp polished carbide, high speed and flood coolant; large stock removal from thick plate needs symmetric passes and stress-relieved (T7x51/T7x52) material to control distortion.

Can 7085-T7651X be welded?

Not readily — weldability is rated poor (20/100). Not fusion weldable (hot cracking, drastic HAZ property loss) — join by riveting, bolting or friction stir welding with post-weld property allowance.

What surface finishes work on 7085-T7651X?

Chromic or boric-sulfuric anodize plus epoxy primer for aerospace corrosion protection; hard anodize possible but grey-tinted, and shot peening or Alclad/paint systems are used on exposed surfaces.

Can 7085-T7651X be formed, bent or molded?

Formed hot as thick plate or die forging; in the aged temper only mild bending/straightening is possible — do stretch/compression stress relief before machining.

What is the maximum service temperature of 7085-T7651X?

7085-T7651X is rated for continuous use to about 120°C (248 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.

What is the difference between 7085-T7451 and 7085-T7352?

T7451 is the default condition — default thick-plate condition: best overall balance of strength, fracture toughness and SCC resistance for machined wing/fuselage structural parts. T7352: forging counterpart of T7351 — maximum SCC/toughness margin in heavy sections at the cost of ~8 % strength. Yield strength is 469 MPa in T7451 versus 421 MPa in T7352.

Can FabDigit make parts in 7085-T7651X?

Yes — 7085-T7651X is available for CNC machining and sheet metal with instant online pricing. Upload a STEP file to get a price and a DFM check.

Sources

  1. International Alloy Designations and Chemical Composition Limits for Wrought Aluminum (Teal Sheets) — The Aluminum Association (2018)
  2. AMS 4413 / AMS 4414 — Aluminum Alloy 7085 Plate and Die Forgings — SAE International (2016)
  3. Alcoa 7085 thick plate and forgings product information — Alcoa / Arconic (2010)
  4. ASM Handbook Vol. 2 — Properties and Selection: Nonferrous Alloys — ASM International (1990)
  5. MMPDS-17 Metallic Materials Properties Development and Standardization — Battelle / FAA (2022)
  6. ASM Handbook Vol. 13B — Corrosion: Materials — 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.