Acta metallurgica et materialia vol:40 issue:3 pages:501-511
The interrelationships between thermomechanical cycling (training), the two way memory effect (TWME) and other, concomitant, effects of training are still points of controversion. A theoretical analysis shows that the results obtained in previous studies are influenced by artifacts resulting from the testing modes. In the present study, those artifacts are avoided by using a uniform deformation mode on a specially designed testing apparatus. The relationships between the training parameters, the TWME and concomitant effects are quantitatively determined. It is shown that the TWME is directly determined by the transformation strain induced during training. Local martensite stabilization, residual deformations of the high temperature shape and shifts of the transformation temperatures show no causal relationship with the TWME and are considered as negative side-effects of training. Those undesirable side-effects can be minimized, without affecting the TWME, by the proper choice of the training parameters. From this, criteria are deduced for the optimum training procedure.