Structure evolution of Cu-based shape memory powder during mechanical alloying

The microstructures of shape memory powders of Cu-Al-Ni prepared from pure powders of Cu, Al and Ni using the mechanical alloying(MA) technique were studied by means of hardness measurement, metallograph observation, XRD and SEM. The hardness reaches the peak as the increase in hardness due to plastic deformation and the decrease in hardness due to kinetic annealing reach a balance. The process of MA leads to the formation of a laminated structure, and the layer becomes thinner with an increase in milling time. The pre-alloyed shape memory powder can be formed by milling at 300 r/min for 50 h using a planetary ball mill.