Aluminum 7108A-T6
Temper · default condition
AA 7108A · EN AlZn5Mg1Zr, AW-7108A
T6 = solution heat treated and artificially aged
Standard stocked condition for welded structural extrusions needing peak strength with good HAZ recovery.
Values for the T6 condition
Other 7108A tempers and conditions
7108A is listed in 6 conditions; see the grade overview at 7108A.
Compare all 6 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
Annealed | Softest condition for severe forming or straightening before re-solution treatment and aging. | 90 | 200 | 20 | 50 HB | 42 % IACS |
Solution heat treated and naturally aged | Formable intermediate condition; strength continues to climb slowly at room temperature, so fabricate then artificially age. | 190 | 300 | 18 | 78 HB | 31 % IACS |
Cooled from hot working and artificially aged | Economical press-quench temper for thin-wall sections where full T6 solution treatment is not required. | 280 | 335 | 11 | 98 HB | 34 % IACS |
Slightly overaged | Choose when sustained tensile loads in humid/chloride service make SCC resistance more important than the last few percent of strength. | 300 | 350 | 12 | 100 HB | 37 % IACS |
T6DefaultThis page Solution heat treated and artificially aged | Standard stocked condition for welded structural extrusions needing peak strength with good HAZ recovery. | 315 | 360 | 12 | 105 HB | 35 % IACS |
T6 with improved mechanical properties | Tightly controlled T6 aging route guaranteeing higher minimum strengths for crash and load-bearing extrusions. | 350 | 390 | 10 | 115 HB | 34 % IACS |
What is 7108A-T6?
7108A-T6 is 7108A in the T6 temper — standard stocked condition for welded structural extrusions needing peak strength with good HAZ recovery. 7108A-T6 has a yield strength of 315 MPa (45.7 ksi) and a tensile strength of 360 MPa (52.2 ksi) — stronger than 79% of aluminum grades. Elongation at break is 12% and the elastic modulus is 70 GPa (10.2 Msi). 7108A-T6 has a density of 2.78 g/cm³ (0.1 lb/in³), heavier than 74% of aluminum grades. It melts at 610°C (1,130 °F).
Advantages
- High strength — 315 MPa (45.7 ksi), better than 79% of aluminum grades
- Readily welded — 85/100, better than 79% of aluminum grades
- Tough — resists crack growth — 30 MPa·√m (27.3 ksi·√in), better than 76% of aluminum grades
Limitations
- Limited service temperature — 120°C (248 °F), worse than 79% of aluminum grades
7108A-T6 properties
Typical room-temperature values for 7108A-T6; 16 are specific to this condition. Other listed values are 7108A reference data and may not represent this condition. Bars are the position among aluminum grades.
Physical3
7108A-T6 has a density of 2.78 g/cm³ (0.1 lb/in³), heavier than 74% of aluminum grades. It melts at 610°C (1,130 °F).
Mechanical13
7108A-T6 has a yield strength of 315 MPa (45.7 ksi) and a tensile strength of 360 MPa (52.2 ksi) — stronger than 79% of aluminum grades. Elongation at break is 12% and the elastic modulus is 70 GPa (10.2 Msi).
Thermal6
7108A-T6 is rated for continuous service to 120°C (248 °F). It conducts heat at 150 W/m·K (86.7 BTU/hr·ft·°F), better than 58% of aluminum grades. Thermal expansion is 23.4 µm/m·K (13 µin/in·°F).
Electrical3
7108A-T6 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 7108A-T6 takes about 200 MJ of energy and emits 12 kg of CO₂ — less than 60% of aluminum grades. Typical recycled content is 25%.
Manufacturability8
7108A-T6's machinability is good (58/100, worse than 54% of aluminum grades); weldability excellent (85/100); formability fair (40/100).
Common Calculations5
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with 7108A-T6
Is 7108A easy to machine?
Machines cleanly in T5/T6/T66 with sharp polished-flute carbide tooling, high speed and generous coolant; annealed and T4 material tends to smear and build up on edges.
Can 7108A be welded?
Designed for MIG/TIG welding with 5356 or 5183 filler — the HAZ naturally re-ages over several weeks to recover roughly 70–80 % of parent strength; avoid excessive heat input and allow post-weld natural aging before proof loading.
Can 7108A be formed, bent or molded?
Extrude and form in O or T4; bending in T6/T66 needs generous radii (≥3–4 t) and preferably a stress-relieved section, and heavy cold work after aging risks cracking.
What surface finishes work on 7108A?
Takes protective sulphuric anodising and powder coating well after alkaline etch and desmut; decorative bright anodising is duller than 6000 series and welds anodise a different shade.
7108A 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 |
|---|---|---|
| ZnPrimary hardener with Mg (MgZn2) | 4.5 – 5.2 | 4.8 |
| Mg | 0.7 – 1.4 | 1 |
| ZrAl3Zr dispersoids control recrystallisation and grain size | 0.12 – 0.25 | 0.16 |
| Si | ≤ 0.1 | 0.05 |
| FeA-variant allows a higher Fe ceiling than base 7108 | ≤ 0.25 | 0.15 |
| Cumax — kept low for weldability/corrosion | ≤ 0.05 | 0.02 |
| Mn | ≤ 0.05 | 0.02 |
| Cr | ≤ 0.05 | 0.01 |
| Ti | ≤ 0.05 | 0.02 |
| Others (each) | ≤ 0.05 | — |
| Others (total) | ≤ 0.15 | — |
| Al | balance | — |
7108A-T6 — frequently asked
What is 7108A-T6 used for?
7108A-T6 is typically used for welded structural extrusions, bicycle components and transport frames. In short: weldable high-strength 7000 series; zr-refined fine grain; HAZ re-ages naturally.
What is the yield strength of 7108A-T6?
7108A-T6 has a typical yield strength of 315 MPa (45.7 ksi) and a tensile strength of 360 MPa (52.2 ksi) — stronger than 79% of aluminum grades. Strength varies by condition: see the 6 listed tempers.
Is 7108A-T6 easy to machine?
Reasonably — machinability is rated good (58/100, worse than 54% of aluminum grades). Machines cleanly in T5/T6/T66 with sharp polished-flute carbide tooling, high speed and generous coolant; annealed and T4 material tends to smear and build up on edges.
Can 7108A-T6 be welded?
Yes — weldability is rated excellent (85/100). Designed for MIG/TIG welding with 5356 or 5183 filler — the HAZ naturally re-ages over several weeks to recover roughly 70–80 % of parent strength; avoid excessive heat input and allow post-weld natural aging before proof loading.
What surface finishes work on 7108A-T6?
Takes protective sulphuric anodising and powder coating well after alkaline etch and desmut; decorative bright anodising is duller than 6000 series and welds anodise a different shade.
Can 7108A-T6 be formed, bent or molded?
Extrude and form in O or T4; bending in T6/T66 needs generous radii (≥3–4 t) and preferably a stress-relieved section, and heavy cold work after aging risks cracking.
What is the maximum service temperature of 7108A-T6?
7108A-T6 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 7108A-T6 and 7108A-O?
T6 is the default condition — standard stocked condition for welded structural extrusions needing peak strength with good HAZ recovery. O: softest condition for severe forming or straightening before re-solution treatment and aging. Yield strength is 315 MPa in T6 versus 90 MPa in O.
Sources
- EN 573-3 Aluminium and aluminium alloys — Chemical composition of wrought products — CEN (2019)
- EN 755-2 Aluminium and aluminium alloys — Extruded rod/bar, tube and profiles: mechanical properties — CEN (2016)
- International Alloy Designations and Chemical Composition Limits for Wrought Aluminum (Teal Sheets) — The Aluminum Association (2018)
- ASM Handbook Vol. 2 — Properties and Selection: Nonferrous Alloys — ASM International (1990)
- ASM Handbook Vol. 13B — Corrosion: Materials (Al-Zn-Mg SCC behaviour) — ASM International (2005)
- Al-Zn-Mg weldable extrusion alloy datasheets (7005/7020/7108 class) — Hydro / Constellium extrusion divisions (2022)
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.