Nj. Wittridge et al., A dislocation-based model for variant selection during the gamma-to-alpha ' transformation, MET MAT T A, 32(4), 2001, pp. 889-901
A phase transformation model is described for variant selection during the
austenite-to-martensite transformation. The model depends entirely on the p
resence of glide dislocations in the deformed austenite. The direct correla
tion between the 24 slip systems of the Bishop and Hill (B-H) crystal plast
icity model and the 24 [112] rotation axes of the Kurdjumov-Sachs (K-S) ori
entation relationship is employed. Two selection criteria, based on slip ac
tivity and permissible dislocation reactions, govern the variants that are
chosen to represent the final transformation texture. The development of th
e model via analysis of the experimental results of Liu and Bunge is descri
bed. The model is applied to the four distinct strain paths: (1) plane stra
in rolling, (2) axisymmetric extension, (3) axisymmetric compression, and (
4) simple shear. Experimental deformation and transformation textures were
produced for comparison purposes via appropriate deformation and quenching
procedures. In each case, the transformation texture predicted using the di
slocation reaction model is in excellent agreement with the experimental fi
ndings.