Copper Alloy GRCop-42
GRCop-42 is a NASA-developed Cu-Cr-Nb alloy strengthened by stable Cr₂Nb dispersoids and optimized for laser powder-bed fusion, with conditions on file from powder through LPBF as-built, stress-relieved and HIP, plus DED and extrusion.
Reference datasheet — GRCop-42 is not in the instant-quote catalog. Upload your part and an engineer will quote it in this grade or suggest the closest stocked equivalent.
What is GRCop-42?
GRCop-42 is a NASA-developed Cu-Cr-Nb alloy strengthened by stable Cr₂Nb dispersoids and optimized for laser powder-bed fusion, with conditions on file from powder through LPBF as-built, stress-relieved and HIP, plus DED and extrusion. Engineers select it for 320 W/m·K thermal conductivity and 80% IACS combined with 275 MPa yield, 455 MPa tensile and 33% elongation, which suits regeneratively cooled rocket engine hardware with fine internal channels. Maximum service temperature is about 700 °C, and hot-gas copper surfaces need coatings against oxidation and blanching. GRCop-84 is the nearest alternative when high-temperature strength matters more than conductivity. GRCop-42 has a density of 8.86 g/cm³ (0.32 lb/in³), heavier than 68% of copper alloy grades. It melts at 1,080°C (1,976 °F). GRCop-42 has a yield strength of 275 MPa (39.9 ksi) and a tensile strength of 455 MPa (66 ksi) — stronger than 57% of copper alloy grades. Elongation at break is 33% and the elastic modulus is 120 GPa (17.4 Msi).
What is GRCop-42 used for?
- rocket combustion chambers
- regen-cooled nozzles
- high-heat-flux components
Advantages
- High service temperature — 700°C (1,292 °F), better than 100% of copper alloy grades
- Conducts heat well — 320 W/m·K (184.9 BTU/hr·ft·°F), better than 84% of copper alloy grades
- High electrical conductivity — 80 % IACS, better than 84% of copper alloy grades
- Ductile — tolerates forming and impact — 33%, better than 78% of copper alloy grades
- Readily welded — 60/100, better than 76% of copper alloy grades
Limitations
- High embodied carbon — 9 kg CO₂/kg, worse than 99% of copper alloy grades
- Needs corrosion protection — 52/100, worse than 93% of copper alloy grades
- Hard to polish — 65/100, worse than 87% of copper alloy grades
GRCop-42 properties
Typical room-temperature values; bars are the position among copper alloy grades.
Physical3
GRCop-42 has a density of 8.86 g/cm³ (0.32 lb/in³), heavier than 68% of copper alloy grades. It melts at 1,080°C (1,976 °F).
Mechanical12
GRCop-42 has a yield strength of 275 MPa (39.9 ksi) and a tensile strength of 455 MPa (66 ksi) — stronger than 57% of copper alloy grades. Elongation at break is 33% and the elastic modulus is 120 GPa (17.4 Msi).
Thermal6
GRCop-42 is rated for continuous service to 700°C (1,292 °F). It conducts heat at 320 W/m·K (184.9 BTU/hr·ft·°F), better than 84% of copper alloy grades. Thermal expansion is 17 µm/m·K (9.44 µin/in·°F).
Electrical3
GRCop-42 conducts electricity at 80 % IACS, better than 84% of copper alloy grades.
Chemical & Environmental3
Corrosion resistance is fair (52/100), worse than 93% of copper alloy grades.
Sustainability4
Producing a kilogram of GRCop-42 takes about 120 MJ of energy and emits 9 kg of CO₂ — more than 98% of copper alloy grades. Typical recycled content is 10%.
Manufacturability8
GRCop-42's machinability is good (55/100, better than 71% of copper alloy grades); weldability good (60/100); formability good (55/100).
Common Calculations5
Values are nominal handbook figures for design screening. Certified mill or lot data ships with every FabDigit order on request.
Strength versus weight in the copper alloy family
Yield strength against density for every copper alloy grade FabDigit runs. GRCop-42 is highlighted; hover a dot for its name, or open the interactive family chart.
Working with GRCop-42
Is GRCop-42 easy to machine?
Machines like a tough dispersion-strengthened copper: use sharp positive-rake carbide/PCD, high speed with low feed, flood coolant and avoid dwelling — the gummy Cu matrix with hard Cr₂Nb particles causes built-up edge and rapid edge rounding.
Can GRCop-42 be welded?
Electron-beam and laser welding are the proven joining routes (used for jacket closeouts and bimetallic Cu–Ni transitions); high thermal conductivity requires high power density and preheat, and filler-free autogenous welds preserve the dispersoid strengthening.
Can GRCop-42 be formed, bent or molded?
Not conventionally castable — parts are made by L-PBF, LP-DED or canned powder extrusion; wrought stock cold-works readily but recovers strength only through the stable Cr₂Nb dispersion, not heat treatment.
GRCop-42 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 |
|---|---|---|
| Cr4 at.% nominal; combines with Nb as Cr₂Nb dispersoids | 3 – 3.6 | 3.3 |
| Nb2 at.% nominal | 2.6 – 3.2 | 2.9 |
| Opowder oxygen, typical AM feedstock limit | ≤ 0.05 | 0.02 |
| Cubalance ~93.8 wt%, matrix | balance |
What surface finishes work on GRCop-42?
Chemical/abrasive-flow polishing of internal cooling channels plus electroless nickel, thermal-barrier or NiCrAlY coatings on hot-gas surfaces to counter copper oxidation and blanching; no anodizing.
Surface treatments FabDigit runs on copper alloy parts — pick them in the quote configurator or call them out on the drawing. Each links to its datasheet in the surface-finish library (thickness, specs, call-out, material verdicts).
How much does GRCop-42 cost?
GRCop-42 is a high-cost copper alloy ($$$$), pricier than about 78% of the materials FabDigit quotes. Part price depends far more on geometry, tolerance and quantity than on the raw stock — upload a CAD file for a live quote.
GRCop-42 — frequently asked
What is GRCop-42 used for?
GRCop-42 is typically used for rocket combustion chambers, regen-cooled nozzles and high-heat-flux components. In short: highest-conductivity printable copper alloy; dispersion-strengthened to 700 °C; proven LPBF rocket-chamber alloy.
What is the yield strength of GRCop-42?
GRCop-42 has a typical yield strength of 275 MPa (39.9 ksi) and a tensile strength of 455 MPa (66 ksi) — stronger than 57% of copper alloy grades.
Is GRCop-42 easy to machine?
Reasonably — machinability is rated good (55/100, better than 71% of copper alloy grades). Machines like a tough dispersion-strengthened copper: use sharp positive-rake carbide/PCD, high speed with low feed, flood coolant and avoid dwelling — the gummy Cu matrix with hard Cr₂Nb particles causes built-up edge and rapid edge rounding.
Can GRCop-42 be welded?
Yes — weldability is rated good (60/100). Electron-beam and laser welding are the proven joining routes (used for jacket closeouts and bimetallic Cu–Ni transitions); high thermal conductivity requires high power density and preheat, and filler-free autogenous welds preserve the dispersoid strengthening.
What surface finishes work on GRCop-42?
Chemical/abrasive-flow polishing of internal cooling channels plus electroless nickel, thermal-barrier or NiCrAlY coatings on hot-gas surfaces to counter copper oxidation and blanching; no anodizing.
Can GRCop-42 be formed, bent or molded?
Not conventionally castable — parts are made by L-PBF, LP-DED or canned powder extrusion; wrought stock cold-works readily but recovers strength only through the stable Cr₂Nb dispersion, not heat treatment.
What is the maximum service temperature of GRCop-42?
GRCop-42 is rated for continuous use to about 700°C (1,292 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
How much does GRCop-42 cost?
GRCop-42 is a high-cost copper alloy ($$$$), pricier than about 78% of the materials FabDigit quotes. Part price depends far more on geometry, tolerance and quantity than on the raw stock — upload a CAD file for a live quote.
Sources
- GRCop-42 Development and Characterization for Additive Manufacturing (NASA technical reports/papers) — NASA Marshall & Glenn Research Centers (2022)
- ASM Handbook Vol. 2 — Properties and Selection: Nonferrous Alloys — ASM International (1990)
- ASM Handbook Vol. 13B — Corrosion: Materials (Copper alloys) — ASM International (2005)
- GRCop-42 AM powder datasheets (gas-atomized Cu-Cr-Nb feedstock) — AM powder producers (2024)
Property data is compiled from published supplier and standards handbooks and normalised for comparison; hardness values on non-Brinell scales are converted approximately for charting only. Manufacturability limits are FabDigit quote-engine defaults and may be relaxed by engineering review. Nothing on this page is a certification — request mill certs, CoC or material test reports with your order.