Preparation of Cu-Cr alloy powder by heat mechanical alloying and Box-Behnken design based optimization

Abstract

Mechanical alloying is a promising method for preparing Cu-Cr alloy powder, while some troublesome challenges in cost and efficiency have yet to be solved. In this work, nano-scale Cu-Cr alloy powder was prepared by co-precipitation and advanced heat mechanical alloying (HMA) processes with low-cost raw materials. Results showed that the co-precipitation treatment by using ammonium hydroxide as the precipitant is an appropriate approach for manufacturing uniformly fine precursor. Box-Behnken design (BBD) was employed to investigate the combined effects of milling temperature (T), milling duration (t) and ball-to-powder mass ratio (R) on the grain size of Cu-Cr alloy powder (GS) and to optimize the HMA process for fine alloy powder production. A second-order polynomial regression model was established and was verified by the analysis of variance (ANOVA), which shows good fit of the experimental data. Three-dimensional (3D) response surfaces were plotted to elucidate the main and interactive effects of the three parameters on the grain size of Cu-Cr alloy powder, and the optimum condition for HMA process was proposed.