A study on the microstructure and properties of Cu-based shape memory alloy produced by hot extrusion of mechanically alloyed powders

Powder Metallurgy is used widely to produce Cubased shape memory alloys having maximum of desired properties. It is better to use P/M to produce nearnet shape alloy products and have better controllability on the composition and grain size. In this study, the highenergy planetary ball milling was applied to convert the elemental powder mixtures of Cu, Al and Ni into prealloyed powders. The effect of milling time on composition and particles size distribution was studied and the prealloyed powders were compacted by pressing and then hot extruded to obtain the final alloy sample. Strain recovery of the bended samples was studied to evaluate the effect of milling on shape memory properties. The densities of samples were calculated in green, sintered and extruded conditions to investigate the changes in the density of the samples, and influence of porosity on shape memory effect. The results showed that milling time has a variable influence on the density of samples, which can takes effect on the shape memory recovery due to amount of porosity. (c) 2012 Elsevier B.V. All rights reserved.