FATIGUE PROPERTIES OF ALLOYS EXHIBITING SPINODAL DECOMPOSITION

Abstract

The mechanical properties of a Cu-2^Co alloy and var ious CuNiFe alloys have been investigated; in addition, thin film work has been conducted on Superston Bronze and fatigued CuNiFe. The fatigue strengths and ratios of the CuNiFe alloys are comparable to the best of the copper alloys; it was obser ved that the alloys are considerably better under fatigue con ditions for widely varying grain size. The high copper CuNiFe fatigue curves exhibited a pronounced discontinuity, and there appears to be some correlation between abruptness and size of the discontinuity and notch sensitivity. Examination of fatigued CuNiFe indicates that a reversion-reprecipitation-ageing process is occurring, the overall sequence generally being in agreement with the theoretical implications of spinodal decomposition.