The thermoelastic martensitic transformation from the B2 to B19′ structures in the Ti-Ni shape memory alloy was observed by in situ scanning electron microscopy in order to investigate the self-accommodation microstructure. Nucleation of the V-shaped habit plane variant cluster (2HPVC) triggers the formation of the hexangular HPVC (6HPVC) that is formed by six habit plane variants in the grain interior. The triangular morphology (3HPVC) is a derivative of 2HPVC. The autocatalytic transformation spreads from the 6HPVCs to the grain boundary and the reverse transformation proceeds like a rewind of the forward transformation. 2HPVC and 6HPVC are the most favorable morphologies for nucleation and growth, respectively, as explained by the analysis of the kinematic compatibility at junction planes.
All Science Journal Classification (ASJC) codes
- Electronic, Optical and Magnetic Materials
- Ceramics and Composites
- Polymers and Plastics
- Metals and Alloys