A Quantitative Micro-Deformation Field Study of Shape Memory Alloys by High Sensitivity Moiré

Abstract

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.

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

“…This implies that the martensite formed has an internally twinned structure. This is different from the case of pseudoelasticity [7] where both habit plane variant formation and detwinning are possible. Detailed microstructure identification by using Electron Back Scattering Diffraction (EBSD) is under way.…”

“…It has several excellent properties like real-time, high sensitivity to in-plane displacement, high spatial resolution and high quality fringe patterns. These unique features make it an exceptionally attractive tool for measuring the microstructure sensitive deformation field of SMAs [6,7]. In the present paper, we investigate the P, + y; martensitic transformation of CuAlNi single crystal SMAs under uniaxial tension by using high sensitivity Moire interferometry.…”