Abstract
The effect of several kinds of pre-treatments on the temperature of diffusionless reverse transformation from martensite to austenite was investigated on an Fe-33%Ni alloy. The main results obtained are as follows.
(1) The T0 temperature (=(Ms+As)/2), at which the chemical free energies of austenite and martensite are equal in the alloy, was constant even if the Ms temperature was varied with different austenitizing treatments.
(2) The As temperature (starting temperature of reverse transformation to austenite) increased markedly with deformation of martensite. It became clear that the reverse transformation was suppressed with deformation of martensite. However, the Af temperature (finishing temperature of reverse transformation) hardly changed with deformation.
(3) Reverse transformation of the ausformed martensite was hardly affected by the degree of ausforming.
