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Aluminum 4145 · temper

Aluminum 4145-T6

Properties of the T6 condition, compared with the other 4145 tempers.

Choose when the repaired casting or brazed assembly is given a full T6 cycle so the 4 % Cu in the deposit precipitation-hardens with the base metal.

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Quote a part in 4145-T64145 overview

What is 4145-T6?

4145-T6 is 4145 in the T6 temper — choose when the repaired casting or brazed assembly is given a full T6 cycle so the 4 % Cu in the deposit precipitation-hardens with the base metal. 4145-T6 has a yield strength of 215 MPa (31.2 ksi) and a tensile strength of 285 MPa (41.3 ksi) — stronger than 57% of aluminum grades. Elongation at break is 2% and the elastic modulus is 72 GPa (10.4 Msi). 4145-T6 has a density of 2.75 g/cm³ (0.0994 lb/in³), heavier than 66% of aluminum grades. It melts at 516°C (961 °F).

Limitations

  • Hard to polish — 35/100, worse than 98% of aluminum grades
  • Limited ductility — 2%, worse than 87% of aluminum grades

4145-T6 properties

Typical room-temperature values for 4145-T6 — 11 properties are specific to this condition; the rest are grade-level values shared by every 4145 temper. Each bar shows where the value sits among the aluminum grades in FabDigit's library — further right is higher.

Physical3

4145-T6 has a density of 2.75 g/cm³ (0.0994 lb/in³), heavier than 66% of aluminum grades. It melts at 516°C (961 °F).

Density2.75 g/cm³0.1 lb/in³
Melting Point (Solidus)516°C961 °F
Liquidus Temperature585°C1,085 °F

Mechanical10

4145-T6 has a yield strength of 215 MPa (31.2 ksi) and a tensile strength of 285 MPa (41.3 ksi) — stronger than 57% of aluminum grades. Elongation at break is 2% and the elastic modulus is 72 GPa (10.4 Msi).

Elastic (Young's) Modulus72 GPa10.4 Msi
Shear Modulus27 GPa3.9 Msi
Bulk Modulus71 GPa10.3 Msi
Poisson's Ratio0.33
Tensile Strength (Ultimate)285 MPa41.3 ksi
Yield Strength (0.2% offset)215 MPa31.2 ksi
Elongation at Break2%
Shear Strength180 MPa26.1 ksi
Fatigue Strength (Endurance Limit)85 MPa12.3 ksi
Hardness, Brinell95 HB

Thermal5

4145-T6 is rated for continuous service to 150°C (302 °F). It conducts heat at 140 W/m·K (80.9 BTU/hr·ft·°F), worse than 52% of aluminum grades. Thermal expansion is 20.7 µm/m·K (11.5 µin/in·°F).

Thermal Conductivity140 W/m·K80.9 BTU/hr·ft·°F
Specific Heat Capacity880 J/kg·K0.21 BTU/lb·°F
Thermal Expansion (CTE, 20–100 °C)20.7 µm/m·K11.5 µin/in·°F
Max Service Temperature (continuous)150°C302 °F
Min Service Temperature-196°C-321 °F

Electrical3

4145-T6 conducts electricity at 33 % IACS, worse than 57% of aluminum grades.

Electrical Conductivity33 % IACS
Electrical Resistivity5.6×10⁻⁸ Ω·m2.2 µΩ·in
Magnetic Responsenon-magnetic

Chemical & Environmental3

Corrosion resistance is fair (42/100), worse than 69% of aluminum grades.

Galvanic Potential (seawater, vs SCE)-0.78 V
Corrosion ResistanceFair42/100
Chemical Resistance SummaryAdequate in dry atmospheres and neutral waters; the 4 % Cu makes it noticeably less corrosion resistant than 4043/4047 and it can be a galvanic cathode to Mg-bearing base metals. Attacked by strong acids and alkalis; avoid chloride-rich wet service without coating.

Sustainability4

Producing a kilogram of 4145-T6 takes about 200 MJ of energy and emits 12 kg of CO₂ — less than 60% of aluminum grades. Typical recycled content is 15%.

Embodied Energy (primary production)200 MJ/kg85,985 BTU/lb
Embodied Carbon (primary production)12 kg CO₂/kg
Embodied Water1,100 L/kg132 gal/lb
Typical Recycled Content15%

Manufacturability8

4145-T6's machinability is good (55/100, worse than 58% of aluminum grades); weldability fair (45/100); formability poor (25/100).

MachinabilityGood55/100
Machinability Rating (AISI 1212 = 100 %)45%
WeldabilityFair45/100
Formability (cold)Poor25/100
CastabilityVery good80/100
Brazeability / SolderabilityExcellent90/100
PolishabilityFair35/100
Anodizing Responsepoor — high Si plus 4 % Cu gives dark grey to mottled, low-integrity anodic films; not suitable for decorative or clear anodizing

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

Working with 4145-T6

Is 4145 easy to machine?

Machinable but the hard primary/eutectic Si abrades tooling — use polished-flute carbide or PCD, high speed, low feed and flood coolant.

Can 4145 be welded?

This is the filler itself: preferred for GTAW/GMAW repair of Cu-bearing 2xxx and 206/319/354/380 castings; do not use on high-Mg 5xxx base metal, and expect low ductility in the deposit.

Can 4145 be formed, bent or molded?

Not a forming alloy — supplied as drawn wire, rod, paste or braze cladding; cold forming of the deposit will crack it.

What surface finishes work on 4145?

Anodizing is poor (dark, mottled); use chemical conversion coating plus paint, or accept a machined/as-welded surface. Polishing tends to reveal Si particles.

4145 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
Si9.3 – 10.710
Cu3.3 – 4.74
Fe≤ 0.8—
Mn≤ 0.15—
Mg≤ 0.15—
Cr≤ 0.15—
Zn≤ 0.2—
Others (each)0.15 total≤ 0.05—
Albalance—

4145-T6 — frequently asked

What is 4145-T6 used for?

4145-T6 is typically used for casting repair welds, weld repair of 206/319/354/380 castings, welding of copper-bearing 2xxx alloys, aluminium brazing filler (BAlSi-3), cladding layer on brazing sheet and salvage welding of aluminium tooling. In short: cu-Si filler for cast aluminum welding.

What is the yield strength of 4145-T6?

4145-T6 has a typical yield strength of 215 MPa (31.2 ksi) and a tensile strength of 285 MPa (41.3 ksi) — stronger than 57% of aluminum grades.

Is 4145-T6 easy to machine?

Reasonably — machinability is rated good (55/100, worse than 58% of aluminum grades). Machinable but the hard primary/eutectic Si abrades tooling — use polished-flute carbide or PCD, high speed, low feed and flood coolant.

Can 4145-T6 be welded?

With care — weldability is rated fair (45/100). This is the filler itself: preferred for GTAW/GMAW repair of Cu-bearing 2xxx and 206/319/354/380 castings; do not use on high-Mg 5xxx base metal, and expect low ductility in the deposit.

What surface finishes work on 4145-T6?

Anodizing is poor (dark, mottled); use chemical conversion coating plus paint, or accept a machined/as-welded surface. Polishing tends to reveal Si particles.

Can 4145-T6 be formed, bent or molded?

Not a forming alloy — supplied as drawn wire, rod, paste or braze cladding; cold forming of the deposit will crack it.

What is the maximum service temperature of 4145-T6?

4145-T6 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 4145-T6?

Yes — 4145-T6 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. AWS A5.10/A5.10M — Welding Consumables, Aluminium and Aluminium-Alloy Rods and Electrodes — AWS (2021)
  2. AWS A5.8/A5.8M — Filler Metals for Brazing and Braze Welding (BAlSi-3) — AWS (2019)
  3. International Alloy Designations and Chemical Composition Limits for Wrought Aluminum (Teal Sheets) — The Aluminum Association (2018)
  4. EN ISO 18273 / EN 573-3 (EN AW-4145) — CEN (2019)
  5. ASM Handbook Vol. 2 — Properties and Selection: Nonferrous Alloys — ASM International (1990)
  6. ASM Handbook Vol. 13B — Corrosion: Materials — ASM International (2005)
  7. Aluminium filler metal ER4145 / 4145 braze rod datasheets — Various filler-metal producers (2023)

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.