Aluminum 2124 · temper
Aluminum 2124-T851
Properties of the T851 condition, compared with the other 2124 tempers.
Standard aerospace/mould plate condition: peak strength with good short-transverse toughness and low residual stress for heavy machining.
What is 2124-T851?
2124-T851 is 2124 in the T851 temper — standard aerospace/mould plate condition: peak strength with good short-transverse toughness and low residual stress for heavy machining. 2124-T851 has a yield strength of 440 MPa (63.8 ksi) and a tensile strength of 490 MPa (71.1 ksi) — stronger than 91% of aluminum grades. Elongation at break is 8% and the elastic modulus is 73.1 GPa (10.6 Msi). 2124-T851 has a density of 2.78 g/cm³ (0.1 lb/in³), heavier than 74% of aluminum grades. It melts at 502°C (936 °F).
Advantages
- High strength — 440 MPa (63.8 ksi), better than 91% of aluminum grades
- Tough — resists crack growth — 34 MPa·√m (30.9 ksi·√in), better than 90% of aluminum grades
- Easy to machine — 78/100, better than 89% of aluminum grades
Limitations
- Needs corrosion protection — 30/100, worse than 98% of aluminum grades
- Difficult to weld — 20/100, worse than 89% of aluminum grades
2124-T851 properties
Typical room-temperature values for 2124-T851 — 15 properties are specific to this condition; the rest are grade-level values shared by every 2124 temper. Each bar shows where the value sits among the aluminum grades in FabDigit's library — further right is higher.
Physical3
2124-T851 has a density of 2.78 g/cm³ (0.1 lb/in³), heavier than 74% of aluminum grades. It melts at 502°C (936 °F).
Mechanical12
2124-T851 has a yield strength of 440 MPa (63.8 ksi) and a tensile strength of 490 MPa (71.1 ksi) — stronger than 91% of aluminum grades. Elongation at break is 8% and the elastic modulus is 73.1 GPa (10.6 Msi).
Thermal6
2124-T851 is rated for continuous service to 150°C (302 °F). It conducts heat at 152 W/m·K (87.8 BTU/hr·ft·°F), better than 66% of aluminum grades. Thermal expansion is 22.9 µm/m·K (12.7 µin/in·°F).
Electrical3
2124-T851 conducts electricity at 38 % IACS, better than 61% of aluminum grades.
Chemical & Environmental3
Corrosion resistance is poor (30/100), worse than 98% of aluminum grades.
Sustainability4
Producing a kilogram of 2124-T851 takes about 210 MJ of energy and emits 12.5 kg of CO₂ — more than 88% of aluminum grades. Typical recycled content is 5%.
Manufacturability7
2124-T851's machinability is very good (78/100, better than 89% of aluminum grades); weldability poor (20/100); formability poor (25/100).
Values are nominal handbook figures for design screening. Certified mill or lot data ships with every FabDigit order on request.
Other 2124 tempers and conditions
2124 is also supplied in 4 other conditions. The full side-by-side table is on the 2124 overview.
- T851Standard aerospace/mould plate condition: peak strength with good short-transverse toughness and low residual stress for heavy machining.440 MPa yield · 128 HB
- T351Naturally aged plate with low residual stress — best choice when machined parts must stay flat and higher toughness/ductility is wanted over peak strength.325 MPa yield · 120 HB
- OSoftest condition for heavy forming or machining prior to solution treatment.75 MPa yield · 47 HB
Working with 2124-T851
Is 2124 easy to machine?
Excellent chip control in T851; use sharp carbide, high speed and flood coolant — plate is stress-relieved so machined parts stay dimensionally stable.
Can 2124 be welded?
Not recommended for fusion welding (hot cracking, loss of temper); join by riveting, bolting or friction-stir welding with qualified procedures.
Can 2124 be formed, bent or molded?
Form in O or T351 condition only; T851 plate is essentially non-formable and should be machined to shape.
What surface finishes work on 2124?
Anodize (chromic/sulfuric per MIL-A-8625) or conversion-coat plus primer is mandatory for corrosion protection; alclad or shot peening improves fatigue/exfoliation life.
2124 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 |
|---|---|---|
| Sicontrolled low for toughness | ≤ 0.2 | — |
| Fecontrolled low for toughness | ≤ 0.3 | — |
| Cu | 3.8 – 4.9 | 4.4 |
| Mn | 0.3 – 0.9 | 0.6 |
| Mg | 1.2 – 1.8 | 1.5 |
| Cr | ≤ 0.1 | — |
| Zn | ≤ 0.25 | — |
| Ti | ≤ 0.15 | — |
| Others (each) | ≤ 0.05 | — |
| Others (total) | ≤ 0.15 | — |
| Al | balance | — |
2124-T851 — frequently asked
What is 2124-T851 used for?
2124-T851 is typically used for aerospace plate, bulkheads and wing skins. In short: high-purity aerospace plate; improved 2024.
What is the yield strength of 2124-T851?
2124-T851 has a typical yield strength of 440 MPa (63.8 ksi) and a tensile strength of 490 MPa (71.1 ksi) — stronger than 91% of aluminum grades. Strength varies by condition: see the 5 listed tempers.
Is 2124-T851 easy to machine?
Yes — machinability is rated very good (78/100, better than 89% of aluminum grades). Excellent chip control in T851; use sharp carbide, high speed and flood coolant — plate is stress-relieved so machined parts stay dimensionally stable.
Can 2124-T851 be welded?
Not readily — weldability is rated poor (20/100). Not recommended for fusion welding (hot cracking, loss of temper); join by riveting, bolting or friction-stir welding with qualified procedures.
What surface finishes work on 2124-T851?
Anodize (chromic/sulfuric per MIL-A-8625) or conversion-coat plus primer is mandatory for corrosion protection; alclad or shot peening improves fatigue/exfoliation life.
Can 2124-T851 be formed, bent or molded?
Form in O or T351 condition only; T851 plate is essentially non-formable and should be machined to shape.
What is the maximum service temperature of 2124-T851?
2124-T851 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.
Can FabDigit make parts in 2124-T851?
Yes — 2124-T851 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
- International Alloy Designations and Chemical Composition Limits for Wrought Aluminum (Teal Sheets) — The Aluminum Association (2018)
- AMS 4101 — Aluminum Alloy Plate 2124-T851 — SAE International (2018)
- EN 573-3 / EN 485-2 wrought aluminium plate — CEN (2019)
- ASM Handbook Vol.2 — Properties and Selection: Nonferrous Alloys — ASM International (1990)
- MMPDS-17 (Metallic Materials Properties Development and Standardization) — Battelle/FAA (2022)
- Aerospace plate alloy datasheets (2124-T851) — Constellium / Arconic (2021)
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.