Aluminum ZL205A · temper
Aluminum ZL205A-T7
Properties of the T7 condition, compared with the other ZL205A tempers.
Over-aged/stabilised for dimensional stability and reduced residual stress in parts running warm or requiring tight tolerances.
What is ZL205A-T7?
ZL205A-T7 is ZL205A in the T7 temper — over-aged/stabilised for dimensional stability and reduced residual stress in parts running warm or requiring tight tolerances. ZL205A-T7 has a yield strength of 360 MPa (52.2 ksi) and a tensile strength of 470 MPa (68.2 ksi) — stronger than 84% of aluminum grades. Elongation at break is 3% and the elastic modulus is 70 GPa (10.2 Msi). ZL205A-T7 has a density of 2.82 g/cm³ (0.102 lb/in³), heavier than 89% of aluminum grades. It melts at 545°C (1,013 °F). T5 is the default condition FabDigit quotes; T7 is available on request or by drawing note.
Advantages
- High service temperature — 200°C (392 °F), better than 90% of aluminum grades
- Easy to machine — 76/100, better than 87% of aluminum grades
- High strength — 360 MPa (52.2 ksi), better than 84% of aluminum grades
Limitations
- Needs corrosion protection — 35/100, worse than 85% of aluminum grades
- Limited formability — 10/100, worse than 81% of aluminum grades
- Limited ductility — 3%, worse than 79% of aluminum grades
ZL205A-T7 properties
Typical room-temperature values for ZL205A-T7 — 9 properties are specific to this condition; the rest are grade-level values shared by every ZL205A temper. Each bar shows where the value sits among the aluminum grades in FabDigit's library — further right is higher.
Physical3
ZL205A-T7 has a density of 2.82 g/cm³ (0.102 lb/in³), heavier than 89% of aluminum grades. It melts at 545°C (1,013 °F).
Mechanical14
ZL205A-T7 has a yield strength of 360 MPa (52.2 ksi) and a tensile strength of 470 MPa (68.2 ksi) — stronger than 84% of aluminum grades. Elongation at break is 3% and the elastic modulus is 70 GPa (10.2 Msi).
Thermal6
ZL205A-T7 is rated for continuous service to 200°C (392 °F). It conducts heat at 150 W/m·K (86.7 BTU/hr·ft·°F), better than 58% of aluminum grades. Thermal expansion is 22.5 µm/m·K (12.5 µin/in·°F).
Electrical3
ZL205A-T7 conducts electricity at 38 % IACS, better than 61% of aluminum grades.
Chemical & Environmental3
Corrosion resistance is fair (35/100), worse than 85% of aluminum grades.
Sustainability4
Producing a kilogram of ZL205A-T7 takes about 200 MJ of energy and emits 12.5 kg of CO₂ — less than 60% of aluminum grades. Typical recycled content is 10%.
Manufacturability8
ZL205A-T7's machinability is very good (76/100, better than 87% of aluminum grades); weldability fair (45/100); formability not recommended (10/100).
Values are nominal handbook figures for design screening. Certified mill or lot data ships with every FabDigit order on request.
Other ZL205A tempers and conditions
ZL205A is also supplied in 4 other conditions. The full side-by-side table is on the ZL205A overview.
- T5DefaultThe standard stocked condition: 440 MPa minimum with 7 % elongation — the best strength/ductility balance for structural castings.320 MPa yield · 105 HB
- T6Peak-strength condition (≥470 MPa, HB≥120) for statically loaded parts where ductility can drop to ~3 %.380 MPa yield · 125 HB
- T7Over-aged/stabilised for dimensional stability and reduced residual stress in parts running warm or requiring tight tolerances.360 MPa yield · 112 HB
- T4Best ductility/toughness combination; used when the casting must be straightened or lightly formed before final ageing.250 MPa yield · 90 HB
Working with ZL205A-T7
Is ZL205A easy to machine?
Machines well in T5/T6 with sharp carbide tools, high speed and flood coolant; chips are short and surfaces finish cleanly.
Can ZL205A be welded?
TIG/MIG possible with matching ZL205A or Al-Cu filler but hot-crack sensitive — preheat, low restraint and post-weld solution + age are recommended.
Can ZL205A be formed, bent or molded?
Casting alloy with long freezing range: needs strong directional solidification, generous risering, chills and careful gating; poor fluidity for thin sections.
What surface finishes work on ZL205A?
Chromic/hard anodizing or chromate conversion plus primer is normal — bare surfaces corrode readily; painted or clad protection advised for outdoor service.
ZL205A 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 |
|---|---|---|
| Cu | 4.6 – 5.3 | 5 |
| Mn | 0.3 – 0.5 | 0.4 |
| Tigrain refiner | 0.15 – 0.35 | 0.25 |
| Cdaccelerates θ' nucleation | 0.15 – 0.25 | 0.2 |
| V | 0.05 – 0.3 | 0.15 |
| Zr | 0.05 – 0.2 | 0.15 |
| B | 0.01 – 0.06 | 0.03 |
| Siimpurity limit | ≤ 0.06 | — |
| Feimpurity limit | ≤ 0.15 | — |
| Mgimpurity limit | ≤ 0.05 | — |
| Znimpurity limit | ≤ 0.1 | — |
| Al | balance | — |
ZL205A-T7 — frequently asked
What is ZL205A-T7 used for?
ZL205A-T7 is typically used for aerospace castings, missile components and brackets. In short: premium aerospace Cu-Al cast; highest-strength cast Al.
What is the yield strength of ZL205A-T7?
ZL205A-T7 has a typical yield strength of 360 MPa (52.2 ksi) and a tensile strength of 470 MPa (68.2 ksi) — stronger than 84% of aluminum grades. Strength varies by condition: see the 5 listed tempers.
Is ZL205A-T7 easy to machine?
Yes — machinability is rated very good (76/100, better than 87% of aluminum grades). Machines well in T5/T6 with sharp carbide tools, high speed and flood coolant; chips are short and surfaces finish cleanly.
Can ZL205A-T7 be welded?
With care — weldability is rated fair (45/100). TIG/MIG possible with matching ZL205A or Al-Cu filler but hot-crack sensitive — preheat, low restraint and post-weld solution + age are recommended.
What surface finishes work on ZL205A-T7?
Chromic/hard anodizing or chromate conversion plus primer is normal — bare surfaces corrode readily; painted or clad protection advised for outdoor service.
Can ZL205A-T7 be formed, bent or molded?
Casting alloy with long freezing range: needs strong directional solidification, generous risering, chills and careful gating; poor fluidity for thin sections.
What is the maximum service temperature of ZL205A-T7?
ZL205A-T7 is rated for continuous use to about 200°C (392 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
What is the difference between ZL205A-T5 and ZL205A-F?
T5 is the default condition — the standard stocked condition: 440 MPa minimum with 7 % elongation — the best strength/ductility balance for structural castings. F: as-cast, un-heat-treated stock — only for machining allowance blanks or before subsequent solution treatment. Yield strength is 320 MPa in T5 versus 110 MPa in F.
Can FabDigit make parts in ZL205A-T7?
Yes — ZL205A-T7 is available for CNC machining with instant online pricing. Upload a STEP file to get a price and a DFM check.
Sources
- ASM Handbook Vol.2 — Properties and Selection: Nonferrous Alloys — ASM International (1990)
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.