The Cyclic Mechanical and Fatigue Properties of Ferroanelastic Beta Prime Gold Cadmium

The fatigue behavior of beta prime Au1.05Cd0.95 alloy was investigated and found to be exceptional for certain orientations with lives of 10,000 to 1,000,000 cycles at total strain amplitudes above 0.05 not uncommon. Fatigue lives were influenced principally by the stress level which controlled the amount of plastic deformation, and stress fatigue resistance was low compared with most metals. Failure always exhibited brittle characteristics. An algorithm was devised to predict mechanical behavior from the twin system orientations and was found in good agreement with experiment for longitudinal strains above 0.04. The cyclic mechanical properties were examined, and a model for the behavior was proposed utilizing previous theories of the restoring force and the Peierls-Nabarro stress for twinning and new concepts. Gold-cadmium was found to have certain strain fatigue resistant applications, particularly in electronics where the alloy's high electrical conductivity is utilized.