Effect of the Primary Microstructures during Training Producers on TWSME in NiTi Alloys (TECHNICAL NOTE)

The influence of the martensitic, martensitic+austenitic and austenitic structures in bending training on two-way shape memory effect (TWSME) in Ni-50.8 at %Ti and Ni-49.9 at %Ti alloys was studied. In addition of the primary structure, the effect of pre-strain, plastic strain, training cycle and training temperature on the TWSME was investigated. The prepared samples were trained in martensitic, martensitic+austenitic and austenitic states with bending deformation. The experimental results indicated that in martensitic state, the TWSME was obtained more than in the others. Also it was shown that the optimum pre-strain and number of training cycles in martensitic state than the other states are more and less, respectively. In addition it was shown that with increasing the training temperature in austenitic state, TWSME decreases.