Strengthening mechanisms in a rapidly solidified and aged Cu-Cr alloy

A single-roller melt spinning method was used to produce Cu-Cr microcrystal alloy ribbons. Upon proper aging treatment, the strength and hardness of the alloy were remarkably enhanced while the conductivity only had a minimal decrease. Grain refinement and coherent dispersion strengthening were proved to be the major factors contributing to the improvement of strength and hardness of the alloy after aging. The degree of coherent strengthening was almost identical with that calculated by the Gerold equation. Compared with the solid solution quenched Cu-Cr alloy, the peak hardness was increased 2.6 times, in which about 27% was attributed to the grain refinement and 73%, in turn, provided by coherent strengthening due to aging precipitation. Neither the solid solution strengthening nor vacancy strengthening had detectable effect on the strength and hardness of the rapidly solidified Cu-Cr alloy.