# Quarter-Hard ASTM B780 Silver-Copper-Nickel Alloy

Quarter-hard ASTM B780 alloy is ASTM B780 alloy in the quarter-hard temper. The graph bars on the material properties cards below compare quarter-hard 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 10 ^{6} psi*

Elongation at Break

4.6 *%*

Poisson's Ratio

0.36

Shear Modulus

30 *GPa* 4.4 *x 10 ^{6} psi*

Shear Strength

230 *MPa* 34 *x 10 ^{3} psi*

Tensile Strength: Ultimate (UTS)

410 *MPa* 59 *x 10 ^{3} psi*

## Thermal Properties

Latent Heat of Fusion

140 *J/g*

Melting Completion (Liquidus)

860 *°C* 1580 *°F*

Specific Heat Capacity

270 *J/kg-K* 0.065 *BTU/lb-°F*

Thermal Expansion

18 *µm/m-K*

## Other Material Properties

Density

10 *g/cm ^{3}* 630

*lb/ft*

^{3}Electrical Conductivity: Equal Volume

74 *% IACS*

Electrical Conductivity: Equal Weight (Specific)

66 *% IACS*

## Common Calculations

Stiffness to Weight: Axial

4.5 *points*

Stiffness to Weight: Bending

14 *points*

Strength to Weight: Axial

11 *points*

Strength to Weight: Bending

12 *points*

Thermal Shock Resistance

20 *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

## Further Reading

ASTM B780: Standard Specification for 75% Silver, 24.5% Copper, 0.5% Nickel Electrical Contact Alloy