PAIRED-MARTENSITE IN Fe-30%Ni SINGLE CRYSTALS

The variants of martensite forming isothermally in Fe-30%Ni single crystals at temperatures above Mb appear in pairs. This was found to be a bulk morphology and one which exhibits strong, non-bursting autocatalysis. Individual pairs are comprised of two lath-shaped wings which meet edge-on along a {100} junction plane, and groups of pairs aligned along the traces of the {100} planes were observed. The major component of the shape-change of a wing was found to be along its long dimension. The role of this shape-change in the autocatalytic formation of the morphology and the relation of paired-martensite to lath and plate martensite are considered.