UNS C70260 (CW111C) Nickel-Silicon Copper
C70260 copper is a copper-nickel alloy formulated for primary forming into wrought products. CW111C is the EN numeric designation for this material. C70260 is the UNS number.
It can have a moderately high electrical conductivity among wrought copper-nickels. In addition, it has the lowest embodied energy and a moderately high thermal conductivity.
The properties of C70260 copper include five common variations. This page shows summary ranges across all of them. For more specific values, follow the links immediately below. The graph bars on the material properties cards further below compare C70260 copper to: wrought copper-nickels (top), all copper alloys (middle), and the entire database (bottom). A full bar means this is the highest value in the relevant set. A half-full bar means it's 50% of the highest, and so on.
Mechanical Properties
Elastic (Young's, Tensile) Modulus
120 GPa 17 x 106 psi
Elongation at Break
9.5 to 19 %
Poisson's Ratio
0.34
Shear Modulus
44 GPa 6.3 x 106 psi
Shear Strength
320 to 450 MPa 47 to 65 x 103 psi
Tensile Strength: Ultimate (UTS)
520 to 760 MPa 75 to 110 x 103 psi
Tensile Strength: Yield (Proof)
410 to 650 MPa 59 to 94 x 103 psi
Thermal Properties
Latent Heat of Fusion
220 J/g
Maximum Temperature: Mechanical
200 °C 400 °F
Melting Completion (Liquidus)
1060 °C 1940 °F
Melting Onset (Solidus)
1040 °C 1910 °F
Specific Heat Capacity
390 J/kg-K 0.093 BTU/lb-°F
Thermal Conductivity
160 W/m-K 90 BTU/h-ft-°F
Thermal Expansion
17 µm/m-K
Electrical Properties
Electrical Conductivity: Equal Volume
40 to 50 % IACS
Electrical Conductivity: Equal Weight (Specific)
40 to 51 % IACS
Otherwise Unclassified Properties
Base Metal Price
31 % relative
Density
8.9 g/cm3 560 lb/ft3
Embodied Carbon
2.7 kg CO2/kg material
Embodied Energy
43 MJ/kg 19 x 103 BTU/lb
Embodied Water
310 L/kg 37 gal/lb
Common Calculations
Resilience: Ultimate (Unit Rupture Work)
46 to 140 MJ/m3
Resilience: Unit (Modulus of Resilience)
710 to 1810 kJ/m3
Stiffness to Weight: Axial
7.3 points
Stiffness to Weight: Bending
18 points
Strength to Weight: Axial
16 to 24 points
Strength to Weight: Bending
16 to 21 points
Thermal Diffusivity
45 mm2/s
Thermal Shock Resistance
18 to 27 points
Alloy Composition
Among wrought copper alloys, the composition of C70260 copper is notable for including silicon (Si) and phosphorus (P). Silicon is used to increase strength at the expense of ductility. It also lowers the melting temperature and raises the fluidity of the alloy. Phosphorus is used as an alloy deoxidizer, and to reduce vulnerability to dezincification.
| Cu | 95.8 to 98.8 | |
| Ni | 1.0 to 3.0 | |
| Si | 0.2 to 0.7 | |
| P | 0 to 0.010 | |
| res. | 0 to 0.5 |
All values are % weight. Ranges represent what is permitted under applicable standards.
Followup Questions
Similar Alloys
Further Reading
ASTM B422: Standard Specification for Copper-Aluminum-Silicon-Cobalt Alloy, Copper-Nickel-Silicon-Magnesium Alloy, Copper-Nickel-Silicon Alloy, Copper-Nickel-Aluminum-Magnesium Alloy, and Copper- Nickel-Tin Alloy Sheet and Strip
ASM Specialty Handbook: Copper and Copper Alloys, J. R. Davis (editor), 2001
CRC Materials Science and Engineering Handbook, 4th ed., James F. Shackelford et al. (editors), 2015