Equal Channel Angular Pressing Technology of CuZnAl Shape Memory Alloy

The equal channel angular pressing(ECAP) process,mechanical properties and microstructure of Cu-25.04%Zn-3.83%Al-0.2%Zr(wt％) shape memory alloy were studied.The alloy could be processed with ECAP at 200℃,250℃,300℃,350℃,but the work-hardening was severe when processed at 200℃ and the repeat numbers of ECAP were limitary.Though 250℃ was higher than the alloy's recrystal temperature,when the numbers of ECAP increased there were cracks on the sample.The grain size grew heavily at 350℃,so the alloy's best temperature of ECAP was 300℃.The alloys Brinell hardness increased rapidly from 149 to 252 through the first ECAP at 300℃,then it increased slowly and tended to be stable with the increasing of the number of ECAP.The alloys grain size did not reduce clearly by ECAP at 300℃,but the grain boundaries were more clear and the grains were more regular.There were more wide-angle equiaxed grains and the microstructure was optimized.