Probabilistic Prediction of the Influence of both Cold Working and Shape Memory Heat Treatment on Transformation Temperature for Ti-41.7Ni-8.5Cu(at%)Shape Memory Alloy
Maho HOSOGI, Nagatoshi OKABE, Toshio SAKUMA and Shuichi Miyazaki
Abstract:The transformation temperatures of shape memory alloy vary with the composition, processing and manufacturing conditions of the alloy. The purpose of the present paper is to clarify the influence of cold working ratio and heat treatment temperature on transformation temperatures, and to propose the formula to estimate the transformation temperatures from modeling. The shape memory alloy used for investigation is Ti-41.7Ni-8.5Cu (at%). As a result, the transformation temperatures depend on the cold working ratio and become lower with increasing cold working ratio. Transformation temperatures also depend on the heat treatment temperature and rise with elevating the heat treatment temperature. Therefore, the transformation temperatures could be formula-modeled considering the effect of the cold working ratio and the heat treatment temperature. The probabilistically estimated formulas were proposed considering the scatter of characteristic value and confidence interval. Key Words:Shape memory alloy, Ti-Ni-Cu alloy, Transformation temperature, Cord working ratio, Shape memory treatment