Martensitic transformation in TiPd shape memory alloys studied by PAC method with 111Cd probes

Perturbed angular correlation (PAC) method was applied to study the martensitic phase transition of the TiPd shape memory alloy doped with 111In/111Cd probe atoms. The hyperfine interaction parameters and their concentration and temperature dependences for probes with cubic and noncubic surroundings of the lattice sites, consistent with the respective crystal structures in martensite and austenite phase, were determined. A strong dependence of the martensite start temperature (MS) and shape of the hysteresis loop (TH) on the small admixture of the In impurities in TiPd compound was evidenced. The observed decrease in the MS depends not only on the amount of the third element, but also on the element itself. The data were compared with those obtained with 181Hf/181Ta probes in TiPd alloy with hafnium admixture.