In Situ Optical Microscopic Examination Techniques of Thermally Induced Displacive Transformations

Abstract

The mechanical (reversible deformation, stress-strain diagrams, etc.) and thermal (transformation temperatures, hysteresis) characteristics of the thermoelastic martensitic transformations are in the focus of many manuscripts, however, other aspects of the transformations are given less attention. The relief formation accompanied with displacive transformations ensures the possibility of the direct observation of the mechanism and physical metallurgical characteristics of the martensite↔austenite transformations. The authors of the present manuscript applied the in situ optical microscopy method successfully using self-developed examination techniques and self-made heating stages to characterize the thermally induced displacive transformations in shape memory alloys (SMAs) and TWIP steels.