Effects of deformation on decomposition of austenite: Part II – Carbide precipitation

Abstract

Carbide precipitation has been studied in three alloy steels subjected to plastic deformation in the austenitic condition prior to transformation. A 1½Ni-1Cr-¼Mo steel is shown to precipitate M₂₃C₆ in austenite when deformed both in the stable (750°C) and metastable (550°C) austenitic state prior to transformation between 600 and 700°C. Again, in a 5Cr-0.2C alloy, M₂₃C₆ was found to precipitate at 550°C in the austenite, but subsequent transformation led to complex structures containing M₇C₃ interphase precipitation and fibres. A 1V-0.2C alloy revealed precipitation of VC in stable austenite at 875°C, which caused solute-depleted zones in which no further precipitation occurred during the γ → α transformation; the bulk of the structure exhibited interphase precipitation and fibrous growth of VC, the latter morphology being encouraged by prior plastic deformation of the austenite.