THE 2-WAY MEMORY EFFECT IN A 50 AT-PERCENT TI-40 AT-PERCENT NI-10 AT-PERCENT CU ALLOY

The two-way memory training across the B2 <--> B19 transformation of a 50 at. % Ti-40 at.% Ni-10 at.% Cu alloy has been investigated here following both the strain and the electrical resistance change. Training loops of the form (P --> M transformation --> strain --> shape recovery on reverse transformation) under applied stress levels of 51, 70.1, 89.2 and 108.3 MPa have been examined. The chief aim of the paper has been both to detect the electrical resistance change across the B2 <--> B19 transformation, which is linearly related to the strain, and to discuss the different contributions related to the electric transport properties. The results found here provide sound support for selecting the electrical resistance as a state control variable in a two-way memory effect device.