UNS C17200 (CW101C) Beryllium Copper
C17200 copper is a lightly alloyed grade of copper, formulated for primary forming into wrought products. CW101C is the EN numeric designation for this material. C17200 is the UNS number. Additionally, the EN chemical designation is CuBe2. Older literature may refer to this material as ASTM Alloy 25, but this is now discouraged.
It has a moderately low electrical conductivity among wrought coppers. In addition, it has a moderately low melting temperature and can have a moderately high tensile strength.
The properties of C17200 copper include fifteen 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 C17200 copper to: wrought coppers (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
1.1 to 37 %
Poisson's Ratio
0.33
Rockwell C Hardness
23 to 43
Shear Modulus
45 GPa 6.5 x 106 psi
Shear Strength
330 to 780 MPa 47 to 110 x 103 psi
Tensile Strength: Ultimate (UTS)
480 to 1380 MPa 70 to 200 x 103 psi
Tensile Strength: Yield (Proof)
160 to 1250 MPa 23 to 180 x 103 psi
Thermal Properties
Latent Heat of Fusion
230 J/g
Maximum Temperature: Mechanical
280 °C 530 °F
Melting Completion (Liquidus)
980 °C 1800 °F
Melting Onset (Solidus)
870 °C 1590 °F
Specific Heat Capacity
390 J/kg-K 0.092 BTU/lb-°F
Thermal Conductivity
110 W/m-K 61 BTU/h-ft-°F
Thermal Expansion
18 µm/m-K
Electrical Properties
Electrical Conductivity: Equal Volume
22 % IACS
Electrical Conductivity: Equal Weight (Specific)
23 % IACS
Otherwise Unclassified Properties
Density
8.8 g/cm3 550 lb/ft3
Embodied Carbon
9.4 kg CO2/kg material
Embodied Energy
150 MJ/kg 63 x 103 BTU/lb
Embodied Water
310 L/kg 37 gal/lb
Common Calculations
Resilience: Ultimate (Unit Rupture Work)
4.2 to 500 MJ/m3
Resilience: Unit (Modulus of Resilience)
110 to 5720 kJ/m3
Stiffness to Weight: Axial
7.6 points
Stiffness to Weight: Bending
19 points
Strength to Weight: Axial
15 to 44 points
Strength to Weight: Bending
16 to 31 points
Thermal Diffusivity
31 mm2/s
Thermal Shock Resistance
16 to 46 points
Alloy Composition
Among wrought copper alloys, the composition of C17200 copper is notable for including beryllium (Be) and aluminum (Al). Beryllium is used to permit precipitation hardening (which increases strength) without much effect on electrical conductivity, but at the cost of substantial toxicity. Aluminum is used to add strength and oxidation resistance.
| Cu | 96.1 to 98 | |
| Be | 1.8 to 2.0 | |
| Ni | 0.2 to 0.6 | |
| Fe | 0 to 0.4 | |
| Si | 0 to 0.2 | |
| Al | 0 to 0.2 | |
| res. | 0 to 0.5 |
All values are % weight. Ranges represent what is permitted under applicable standards.
Followup Questions
Similar Alloys
Further Reading
ASTM B196: Standard Specification for Copper-Beryllium Alloy Rod and Bar
ASTM B194: Standard Specification for Copper-Beryllium Alloy Plate, Sheet, Strip, and Rolled Bar
Copper: Its Trade, Manufacture, Use, and Environmental Status, Gunter Joseph, 2001
Properties and Selection: Nonferrous Alloys and Special-Purpose Materials, ASM Handbook vol. 2, ASM International, 1993