2 WAY SHAPE MEMORY EFFECT OBTAINED BY STABILIZED STRESS-INDUCED MARTENSITE IN CU-ZN-AL-CO AND CU-AL-MN ALLOYS

Two way shape memory has been achieved in Cu-Zn-Al-Co and Co-Al-Mn alloys by a training process based on the stabilisation of stress induced martensite. The effect of training temperature on the amount of two way shape memory obtained has been studied by training at various temperatures of between 50-degrees-C and 170-degrees-C above the A(f) After training the samples were thermally cycled various times (up to 100) through their martensitic transformation temperatures in the absence of applied stress to evaluate the degree of recovery of both the hot and cold shape and hence assess the two way shape memory effect. The results obtained showed that there existed an optimum training temperature at which maximum two way shape memory was observed.