Magnesium Alloy LA141A-T7
Temper · default condition
ASTM LA141A · UNS M14141
T7 = solution heat treated and overaged (stabilized)
Standard aerospace supply condition per MIL-M-46130; best compromise of strength, ductility and dimensional stability against room-temperature aging.
Values for the T7 condition
Other LA141A tempers and conditions
LA141A is listed in 4 conditions; see the grade overview at LA141A.
Compare all 4 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
Annealed | Choose for maximum room-temperature formability (deep drawing, stretch forming) before final stabilizing treatment. | 95 | 132 | 25 | 45 HB | 14.5 % IACS |
As fabricated | Mill condition for extrusions and plate that will be machined and stabilized by the user; properties are position- and lot-dependent. | 110 | 145 | 20 | 52 HB | 14 % IACS |
T7DefaultThis page Solution heat treated and overaged (stabilized) | Standard aerospace supply condition per MIL-M-46130; best compromise of strength, ductility and dimensional stability against room-temperature aging. | 117 | 150 | 18 | 55 HB | — |
Strain hardened and partially annealed, half hard | Cold-rolled sheet condition offering somewhat higher yield strength than T7 where forming demands are modest; less dimensionally stable over time. | 145 | 165 | 10 | 62 HB | 13.5 % IACS |
What is LA141A-T7?
LA141A-T7 is LA141A in the T7 temper — standard aerospace supply condition per MIL-M-46130; best compromise of strength, ductility and dimensional stability against room-temperature aging. LA141A-T7 has a yield strength of 117 MPa (17 ksi) and a tensile strength of 150 MPa (21.8 ksi) — weaker than 78% of magnesium alloy grades. Elongation at break is 18% and the elastic modulus is 43 GPa (6.24 Msi). LA141A-T7 has a density of 1.35 g/cm³ (0.0488 lb/in³), lighter than 100% of magnesium alloy grades. It melts at 570°C (1,058 °F).
Advantages
- Lightweight — 1.35 g/cm³ (0.0488 lb/in³), better than 100% of magnesium alloy grades
- Forms and bends easily — 85/100, better than 100% of magnesium alloy grades
- Ductile — tolerates forming and impact — 18%, better than 95% of magnesium alloy grades
Limitations
- Limited service temperature — 65°C (149 °F), worse than 100% of magnesium alloy grades
- Needs corrosion protection — 8/100, worse than 100% of magnesium alloy grades
- Hard to polish — 45/100, worse than 93% of magnesium alloy grades
- Poor heat conductor — 55 W/m·K (31.8 BTU/hr·ft·°F), worse than 90% of magnesium alloy grades
- Low strength — 117 MPa (17 ksi), worse than 78% of magnesium alloy grades
LA141A-T7 properties
Typical room-temperature values for LA141A-T7; 10 are specific to this condition. Other listed values are LA141A reference data and may not represent this condition. Bars are the position among magnesium alloy grades.
Physical3
LA141A-T7 has a density of 1.35 g/cm³ (0.0488 lb/in³), lighter than 100% of magnesium alloy grades. It melts at 570°C (1,058 °F).
Mechanical12
LA141A-T7 has a yield strength of 117 MPa (17 ksi) and a tensile strength of 150 MPa (21.8 ksi) — weaker than 78% of magnesium alloy grades. Elongation at break is 18% and the elastic modulus is 43 GPa (6.24 Msi).
Thermal6
LA141A-T7 is rated for continuous service to 65°C (149 °F). It conducts heat at 55 W/m·K (31.8 BTU/hr·ft·°F), worse than 90% of magnesium alloy grades. Thermal expansion is 26.5 µm/m·K (14.7 µin/in·°F).
Electrical3
LA141A-T7 conducts electricity at 14 % IACS, worse than 58% of magnesium alloy grades.
Chemical & Environmental3
Corrosion resistance is not recommended (8/100), worse than 100% of magnesium alloy grades.
Sustainability4
Producing a kilogram of LA141A-T7 takes about 400 MJ of energy and emits 32 kg of CO₂ — more than 98% of magnesium alloy grades. Typical recycled content is 5%.
Manufacturability8
LA141A-T7's machinability is excellent (88/100, worse than 99% of magnesium alloy grades); weldability fair (45/100); formability excellent (85/100).
Common Calculations5
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with LA141A-T7
Is LA141A easy to machine?
Cuts extremely freely with sharp, high-rake carbide tools at high speed and dry or with mineral oil — never water-based coolant; collect and inert chips/fines, which are pyrophoric and can react with water to release hydrogen.
Can LA141A be welded?
GTAW or friction stir welding under very clean, high-purity argon with tight moisture control; Li oxidises and burns readily, joints lose strength and corrosion resistance, so mechanical fastening or FSW is preferred.
Can LA141A be formed, bent or molded?
Excellent cold formability thanks to the BCC β matrix — bending, deep drawing and stretch forming are feasible at room temperature, with warm forming (100–150 °C) for severe shapes; avoid hold times at temperature that trigger over-aging.
What surface finishes work on LA141A?
Never leave bare: apply chromate or chrome-free conversion coating, HAE/Dow-17 anodic or micro-arc oxidation, then a sealed epoxy/polyurethane topcoat; isolate from all dissimilar metals with insulating washers and wet sealant to prevent violent galvanic attack.
LA141A 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 |
|---|---|---|
| Liβ-phase stabiliser; >11% Li gives BCC structure | 13 – 15 | 14 |
| Al | 1 – 1.5 | 1.25 |
| Siimpurity limit | ≤ 0.1 | — |
| Feimpurity limit, corrosion critical | ≤ 0.01 | — |
| Cuimpurity limit | ≤ 0.01 | — |
| Niimpurity limit, corrosion critical | ≤ 0.01 | — |
| Naimpurity limit | ≤ 0.01 | — |
| Others, each | ≤ 0.05 | — |
| Others, total | ≤ 0.3 | — |
| Mg | balance | — |
LA141A-T7 — frequently asked
What is LA141A-T7 used for?
LA141A-T7 is typically used for satellite structural panels, aerospace weight-critical brackets and specialty ultra-light frames. In short: lightest structural magnesium; cold-formable Mg-Li sheet; 65 °C service limit.
What is the yield strength of LA141A-T7?
LA141A-T7 has a typical yield strength of 117 MPa (17 ksi) and a tensile strength of 150 MPa (21.8 ksi) — weaker than 78% of magnesium alloy grades. Strength varies by condition: see the 4 listed tempers.
Is LA141A-T7 easy to machine?
Yes — machinability is rated excellent (88/100, worse than 99% of magnesium alloy grades). Cuts extremely freely with sharp, high-rake carbide tools at high speed and dry or with mineral oil — never water-based coolant; collect and inert chips/fines, which are pyrophoric and can react with water to release hydrogen.
Can LA141A-T7 be welded?
With care — weldability is rated fair (45/100). GTAW or friction stir welding under very clean, high-purity argon with tight moisture control; Li oxidises and burns readily, joints lose strength and corrosion resistance, so mechanical fastening or FSW is preferred.
What surface finishes work on LA141A-T7?
Never leave bare: apply chromate or chrome-free conversion coating, HAE/Dow-17 anodic or micro-arc oxidation, then a sealed epoxy/polyurethane topcoat; isolate from all dissimilar metals with insulating washers and wet sealant to prevent violent galvanic attack.
Can LA141A-T7 be formed, bent or molded?
Excellent cold formability thanks to the BCC β matrix — bending, deep drawing and stretch forming are feasible at room temperature, with warm forming (100–150 °C) for severe shapes; avoid hold times at temperature that trigger over-aging.
What is the maximum service temperature of LA141A-T7?
LA141A-T7 is rated for continuous use to about 65°C (149 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
What is the difference between LA141A-T7 and LA141A-H24?
T7 is the default condition — standard aerospace supply condition per MIL-M-46130; best compromise of strength, ductility and dimensional stability against room-temperature aging. H24: cold-rolled sheet condition offering somewhat higher yield strength than T7 where forming demands are modest; less dimensionally stable over time. Yield strength is 117 MPa in T7 versus 145 MPa in H24.
Sources
- MIL-M-46130 — Magnesium-Lithium Alloy (LA141A) Sheet and Plate — US DoD (1970)
- ASM Handbook Vol.2 — Properties and Selection: Nonferrous Alloys and Special-Purpose Materials (Magnesium-Lithium alloys) — ASM International (1990)
- MIL-HDBK-5 / MMPDS — Magnesium alloy design allowables — US DoD / Battelle (1998)
- ASTM B951 / UNS M14141 designation practice for magnesium alloys — ASTM International (2011)
- ASM Alloy Phase Diagrams — Mg-Li system — ASM International (2016)
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.