Reverse transformation mechanism of martensite to austenite in a metastable austenitic alloy

The reverse transformation of martensite to austenite in a metastable austenitic alloy was investigated during continuous heating followed by isothermal holding. The diffusionless reverse transformation occurred irrespective of heating rate during continuous heating, resulting in lath-shaped austenite with high dislocation density. During isothermal holding, the equiaxed grains are nucleated and grow due to the diffusive reverse transformation. With further holding time, the diffusionlessly formed austenite laths were recovered to be subgrains. These results are summarized by the reverse transformation–temperature–time diagram.