Tensile deformation behavior of a thermally exposed carbide free bainitic steel

Abstract

The article primarily concentrates on the extent of degeneration of microstructure of a carbide free bainitic steel while being exposed at high temperature vis-à-vis its effect on the mechanical properties. The as-received (AR) materials were exposed at different temperatures for a fixed duration and subsequently thoroughly characterized by employing several techniques suitable for microstructural and mechanical property evaluations. It was interesting to notice that both the amount of retained austenite as well as its C concentration were decreasing with higher temperature making it more unstable which could be reflected from the decreasing trend in the value of true strain that indicates the point of instability. It was observed that the dislocation annihilation coefficient (k₂) was increased while the corresponding storage coefficient (k₁) did not change much with the increase in exposure temperature compared to the AR sample.