Using high sensitivity Moir6 interference technology, the full deformation fields about the stressinduced martensitic transformation P, + ' )' ; of single crystal CuAlNi shape memory alloys (SMAs) are obtained.A straight and sharp interface between martensite and parent phases and its motion during transformation process are clearly observed. The elastic anisotropic properties of the crystal are also quantitatively characterized by this technique. The results show that there is no deformation incompatibility between the two phases, which is different from that of pseudoelasticity where another stress-induced martensitic transformation PI occurs. The present results provide an accurate experimental solution for the phase transformation problem in solids.

Quantitative micro-macro combined experimental research on the deformation field of single crystal CuAINi shape memory alloy (SMA) is performed by using high sensitivity Moiré technique. The study is focused on the micro-macro correspondence of the deformation behavior of single crystal uniaxial tensile specimen during stress induced forward and reverse transformations. The aim of the experiment is to quantitatively relate the macroscopic applied stress with the deformation field in the mesoscale. The large deformation due to the lattice distortion during transformation was first successfully recorded by Moiré interferometry. Some important microstructure-related deformation features of single crystal SMA under uniaxial tension are first reported.