Copper Alloy GRCop-84
GRCop-84 is the higher Cr and Nb content member of the NASA Cu-Cr-Nb family, supplied as gas-atomised powder for LPBF (as-built, stress-relieved, HIP), DED, HIP-PM and extrusion.
Reference datasheet — GRCop-84 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.
GRCop-84 tempers and conditions
GRCop-84 is supplied in one standard condition, HIP-PM.
Supply forms, finishes and certifications
Ways GRCop-84 is supplied — form, process route, surface or paperwork — without a datasheet of their own. The property values above apply.
| Option | What it is | Type |
|---|---|---|
EXT | Extruded | Supply form |
DED-AB | DED / Laser-blown-powder deposited, as-deposited | Printing process |
LPBF-AB | L-PBF As-Built | Printing process |
LPBF-HIPDefault | L-PBF + HIP | Surface finish |
LPBF-SR | L-PBF + Stress Relief / Anneal | Surface finish |
What is GRCop-84?
GRCop-84 is the higher Cr and Nb content member of the NASA Cu-Cr-Nb family, supplied as gas-atomised powder for LPBF (as-built, stress-relieved, HIP), DED, HIP-PM and extrusion. It is chosen where high-temperature strength governs: 420 MPa yield, 530 MPa tensile, 22% elongation, 140 HB and service to about 800 °C, while still delivering 285 W/m·K and 65% IACS. The trade-off against GRCop-42 is lower conductivity, lower ductility and harder machining; the Cr₂Nb dispersion is thermally stable and cannot be age-hardened, and casting is not an option. GRCop-84 has a density of 8.76 g/cm³ (0.316 lb/in³), heavier than 51% of copper alloy grades. It melts at 1,070°C (1,958 °F). GRCop-84 has a yield strength of 420 MPa (60.9 ksi) and a tensile strength of 530 MPa (76.9 ksi) — stronger than 83% of copper alloy grades. Elongation at break is 22% and the elastic modulus is 128 GPa (18.6 Msi).
What is GRCop-84 used for?
- rocket engine liners
- thrust chambers
- aerospace heat exchangers
Advantages
- High service temperature — 800°C (1,472 °F), better than 100% of copper alloy grades
- High strength — 420 MPa (60.9 ksi), better than 83% of copper alloy grades
- Conducts heat well — 285 W/m·K (164.7 BTU/hr·ft·°F), better than 82% of copper alloy grades
- High electrical conductivity — 65 % IACS, better than 82% of copper alloy grades
Limitations
- Needs corrosion protection — 40/100, worse than 100% of copper alloy grades
- Hard to polish — 60/100, worse than 92% of copper alloy grades
- High embodied carbon — 5 kg CO₂/kg, worse than 86% of copper alloy grades
GRCop-84 properties
Typical room-temperature values; bars are the position among copper alloy grades.
Physical3
GRCop-84 has a density of 8.76 g/cm³ (0.316 lb/in³), heavier than 51% of copper alloy grades. It melts at 1,070°C (1,958 °F).
Mechanical12
GRCop-84 has a yield strength of 420 MPa (60.9 ksi) and a tensile strength of 530 MPa (76.9 ksi) — stronger than 83% of copper alloy grades. Elongation at break is 22% and the elastic modulus is 128 GPa (18.6 Msi).
Thermal6
GRCop-84 is rated for continuous service to 800°C (1,472 °F). It conducts heat at 285 W/m·K (164.7 BTU/hr·ft·°F), better than 82% of copper alloy grades. Thermal expansion is 16.5 µm/m·K (9.17 µin/in·°F).
Electrical3
GRCop-84 conducts electricity at 65 % IACS, better than 82% of copper alloy grades.
Chemical & Environmental3
Corrosion resistance is fair (40/100), worse than 100% of copper alloy grades.
Sustainability4
Producing a kilogram of GRCop-84 takes about 60 MJ of energy and emits 5 kg of CO₂ — more than 69% of copper alloy grades. Typical recycled content is 5%.
Manufacturability8
GRCop-84's machinability is fair (45/100, better than 64% of copper alloy grades); weldability good (55/100); formability fair (40/100).
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-84 is highlighted; hover a dot for its name, or open the interactive family chart.
Working with GRCop-84
Is GRCop-84 easy to machine?
Gummy like copper but abrasively loaded with hard Cr₂Nb particles — use sharp uncoated or diamond-coated carbide, high speed/light feed, flood coolant, and expect faster tool wear than CuCrZr.
Can GRCop-84 be welded?
Electron-beam and laser welding are preferred (narrow HAZ keeps the dispersoid fine); avoid high-heat-input arc processes and never solution-anneal expecting precipitation — Cr₂Nb is thermally stable, not age-hardenable.
Can GRCop-84 be formed, bent or molded?
Not a casting alloy — it must be made by rapid solidification (gas atomization) then L-PBF, DED, HIP or extrusion; hot working around 700–850 °C is possible, cold formability is limited.
GRCop-84 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 |
|---|---|---|
| Cr8 at% — forms Cr2Nb dispersoid | 6.2 – 6.9 | 6.5 |
| Nb4 at% — stoichiometric with Cr for Cr2Nb | 5.4 – 6.1 | 5.8 |
| Opowder oxygen pickup, typical AM powder limit | ≤ 0.05 | 0.02 |
| Cu≈87.7 wt% | balance |
What surface finishes work on GRCop-84?
Cannot be anodized; abrasive-flow or chemical polishing of internal channels, then electroless/electrolytic nickel or a thermal-barrier/oxidation coating for hot-gas surfaces.
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-84 cost?
GRCop-84 is a high-cost copper alloy ($$$$), pricier than about 78% of the materials FabDigit quotes. Part price depends far more on geometry, tolerance and quantity than on the raw stock — upload a CAD file for a live quote.
GRCop-84 — frequently asked
What is GRCop-84 used for?
GRCop-84 is typically used for rocket engine liners, thrust chambers and aerospace heat exchangers. In short: strongest GRCop variant; usable to 800 °C; conductive high-temperature AM copper.
What is the yield strength of GRCop-84?
GRCop-84 has a typical yield strength of 420 MPa (60.9 ksi) and a tensile strength of 530 MPa (76.9 ksi) — stronger than 83% of copper alloy grades.
Is GRCop-84 easy to machine?
Reasonably — machinability is rated fair (45/100, better than 64% of copper alloy grades). Gummy like copper but abrasively loaded with hard Cr₂Nb particles — use sharp uncoated or diamond-coated carbide, high speed/light feed, flood coolant, and expect faster tool wear than CuCrZr.
Can GRCop-84 be welded?
Yes — weldability is rated good (55/100). Electron-beam and laser welding are preferred (narrow HAZ keeps the dispersoid fine); avoid high-heat-input arc processes and never solution-anneal expecting precipitation — Cr₂Nb is thermally stable, not age-hardenable.
What surface finishes work on GRCop-84?
Cannot be anodized; abrasive-flow or chemical polishing of internal channels, then electroless/electrolytic nickel or a thermal-barrier/oxidation coating for hot-gas surfaces.
Can GRCop-84 be formed, bent or molded?
Not a casting alloy — it must be made by rapid solidification (gas atomization) then L-PBF, DED, HIP or extrusion; hot working around 700–850 °C is possible, cold formability is limited.
What is the maximum service temperature of GRCop-84?
GRCop-84 is rated for continuous use to about 800°C (1,472 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
How much does GRCop-84 cost?
GRCop-84 is a high-cost copper alloy ($$$$), 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-84: A High-Temperature Copper Alloy for High-Heat-Flux Applications (NASA/TM-2005-213566) — NASA Glenn Research Center (2005)
- Mechanical and thermophysical property data for L-PBF GRCop-84 / GRCop-42 — NASA MSFC additive manufacturing reports (2021)
- Cu-Cr-Nb (GRCop) AM powder datasheets — AM powder suppliers (2023)
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.