抄録
Pseudoelastic behavior and electric resistivity changes during a tensile straining-unloading sequence were observed in a polycrystalline Cu–Zn–Al shape memory alloy (SMA), at various temperatures above Af. The results were compared to those predicted on the basis of the ‘modified’ Taylor scheme and data from single crystals in regard to the yield stress, resistivity changes with strain and stress hysteresis. The scheme has been demonstrated to be successful in predicting the yield stress of polycrystalline SMA, although some disagreement was noticed between the observation and the prediction. Similar disagreements were found in the results other than yield stress, and they tended to be larger with increasing test temperature. They were consistently interpreted as a result of the formation of an auxiliary martensite other than that found in single crystals. The present scheme is useful in relating the pseudoelastic behavior of single and polycrystalline SMA quantitatively to each other, and also in providing information on deformation mechanisms which participate exclusively in the deformation of polycrystalline SMA.
