Infiltrated ASTM B631 Class A Silver-Tungsten Alloy
Infiltrated ASTM B631 class A is a type of ASTM B631 class A. Cited properties are appropriate for the as-fabricated (no temper or treatment) condition. The graph bars on the material properties cards below compare infiltrated ASTM B631 class A 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
220 GPa 32 x 106 psi
Flexural Strength
830 MPa 120 x 103 psi
Poisson's Ratio
0.3
Rockwell B Hardness
95
Shear Modulus
85 GPa 12 x 106 psi
Tensile Strength: Ultimate (UTS)
480 MPa 70 x 103 psi
Thermal Properties
Latent Heat of Fusion
160 J/g
Specific Heat Capacity
160 J/kg-K 0.038 BTU/lb-°F
Thermal Conductivity
420 W/m-K 240 BTU/h-ft-°F
Thermal Expansion
11 µm/m-K
Electrical Properties
Electrical Conductivity: Equal Volume
47 % IACS
Electrical Conductivity: Equal Weight (Specific)
29 % IACS
Otherwise Unclassified Properties
Density
15 g/cm3 910 lb/ft3
Embodied Carbon
43 kg CO2/kg material
Embodied Energy
670 MJ/kg 290 x 103 BTU/lb
Common Calculations
Stiffness to Weight: Axial
8.5 points
Stiffness to Weight: Bending
14 points
Strength to Weight: Axial
9.2 points
Strength to Weight: Bending
9.4 points
Thermal Diffusivity
180 mm2/s
Thermal Shock Resistance
15 points
Alloy Composition
| W | 68.6 to 75 | |
| Ag | 25 to 29 | |
| Co | 0 to 1.0 | |
| C | 0 to 0.2 | |
| Cu | 0 to 0.2 | |
| res. | 0 to 1.0 |
All values are % weight. Ranges represent what is permitted under applicable standards.
Followup Questions
Similar Alloys
Further Reading
ASTM B631: Standard Specification for Silver-Tungsten Electrical Contact Materials
Tungsten: Properties, Chemistry, Technology of the Element, Alloys, and Chemical Compounds, Erik Lassner and Wolf-Dieter Schubert, 1999