Reversible martensitic transformation, ageing and low-temperature tempering of iron–carbon martensite

Reversible martensitic transformation was observed in Fe-based high-carbon alloys at temperatures when none lattice defects (including divacancies) could diffuse. Formation and behavior of carbon-vacancy clusters was studied and discussed. Chemical composition of hexagonal ɛ-carbide is determined as Fe3C. The effect of particle size and ɛ-carbide/martensite orientation relationship on the ɛ-carbide → cementite transformation is discussed.