Computer Simulation of Transformation Textures in Steels

Abstract

Computer simulation study has been made on the martensite texture of steels transformed from rolled austenite having the Cu-type rolled texture; the aim is to appraise variant selection rules so far proposed, i.e. "Active slip (AS) system model", "BOKROS-PARKER (BP) model", and "Twinning shear (TS) model". 360 or 720 initial orientations of austenite composing the Cu-type texture were generated using the random number, and individual orientations were transformed into martensite orientations using KURDJUMOV-SACHS, NISHIYAMA or BAIN relation in a manner of Monte Carlo method.
Pole figures of {001} structure simulated in this way were compared with experimentally determined pole figures by H. ABE et al.; the materials were Fe-25.7% Ni and Fe-30.2% Ni alloys heavily rolled in the austenitic state and transformed into martensite after rolling. The AS model and BP model were not successful in simulating the observation, but the TS model, when applied to the anti-rolling stress (i.e. stress with the sign opposite to the rolling stress), was able to explain fairly well the pole distributions of dislocated martensite texture of the Fe-25.7% Ni alloy.