Abstract
To demonstrate the ability of the coristitutive model which was developed by the authors, example calculations are conducted for the transformation behavior of shape memory alloys. The problem calculated here is described as below. The polycrystalline Ti-Ni shape memory alloy with austenitic phase is first set to be under the stress free condition. The material is cooled down below the martensite finish temperature to occur the martensite phase transformation. The orientations of martensite variants are randomly distributed in the space so as to accomplish the state of the material free from the macroscopic strain. Then uniaxial tensile loading is applied to cause martensite variant reorientation. The material shows the inelastic stress-strain curve during this loading path. Then the load is removed where the residual strain of transformation remains at the stress free state. Next, the material is heated up to above the reverse transformation finish temperature. The residual strain disappears during this process and the shape memory effect is realized. Computational results by the constitutive model for these loading paths are revealed to be reasonable in comparing with experimental observations.
