On the Full-Field Deformation of Single Crystal CuAlNi Shape Memory Alloys-Stress-Induced β₁ → γ'₁ Martensitic Transformation

Abstract
Using high sensitivity Moiré interference technology, the full deformation fields about the stress-induced martensitic transformation β₁ → γ₁' 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 β₁ → β₁' occurs. The present results provide an accurate experimental solution for the phase transformation problem in solids.