ASTM B780 Silver-Copper-Nickel Electrical Contact Alloy
ASTM B780 alloy is a precious metal alloy formulated for use in electrical contacts.
The properties of ASTM B780 alloy include six 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 ASTM B780 alloy to: precious metal electrical contact alloys (top), all alloys in the same category (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
83 GPa 12 x 106 psi
Elongation at Break
1.1 to 9.1 %
Poisson's Ratio
0.36
Shear Modulus
30 GPa 4.4 x 106 psi
Shear Strength
200 to 340 MPa 28 to 49 x 103 psi
Tensile Strength: Ultimate (UTS)
330 to 590 MPa 48 to 86 x 103 psi
Thermal Properties
Latent Heat of Fusion
140 J/g
Specific Heat Capacity
270 J/kg-K 0.065 BTU/lb-°F
Thermal Expansion
18 µm/m-K
Other Material Properties
Density
10 g/cm3 630 lb/ft3
Electrical Conductivity: Equal Volume
70 to 76 % IACS
Electrical Conductivity: Equal Weight (Specific)
62 to 68 % IACS
Common Calculations
Stiffness to Weight: Axial
4.5 points
Stiffness to Weight: Bending
14 points
Strength to Weight: Axial
9.1 to 16 points
Strength to Weight: Bending
11 to 15 points
Thermal Shock Resistance
16 to 29 points
Alloy Composition
| Ag | 74 to 76 | |
| Cu | 23.5 to 25.7 | |
| Ni | 0.35 to 0.65 | |
| Zn | 0 to 0.060 | |
| Fe | 0 to 0.050 | |
| Cd | 0 to 0.050 | |
| Pb | 0 to 0.030 |
All values are % weight. Ranges represent what is permitted under applicable standards.
Followup Questions
Similar Alloys
Further Reading
ASTM B780: Standard Specification for 75% Silver, 24.5% Copper, 0.5% Nickel Electrical Contact Alloy