The crystallographic mechanism of the martensite reaction in iron-carbon alloys

Crystal Geometry and Mechanisms of Phase Transformation in Crystallins Solids

“…It was also in 1948 that Jaswon and Wheeler introddced the application (10) of matrix algebra to the analysis of the austenite-martensite transformation. Bowles in 1951 concluded that the surface relief effects he observed, (11) similar to those in Fig. 1, must have been produced by a plane of zero average macroscopic distortion and Machlin and Cohen, in the same year, deduced (12) from a scratch measurement determination of the transformation distortion matrix that the (259) habit plane in steels is undistorted and unrotated.…”

Crystallographic analysis of ferrous martensite morphology

“…7 (c). In fact, Bowles (1951) pointed out that the martensite needles elongated in the (101), direction align on a {lll}, plane, and Kelly and Nutting (1961) confirmed the existence of the (101), martensite needles by means of transmission electron microscopy. In the present model, it is implicitly assumed that the nucleation of the subunits is accelerated by the presence of dislocations.…”

“…The martensite of Fe-C binary alloys, containing less than about 0.4 wt% C, exhibits a lathlike shape elongated in the (IOl), growth direction (Bowles 1951, Kelly andNutting 1961) with the habit plane close to {lll}, (Bowles 1951, Marder and Krauss 1969, Schonen, Nilles and Owen 1971, Davenport 1981, Wakasa and Wayman 1981 and is highly dislocated (Kelly and Nutting 1961, Wakasa and Wayman 1981b, Sandvik and Wayman 1982, Sarikaya and Thomas 1982, while that containing more than about 0.5 wt% C is plate-like twinned martensite, the frequency of twinning being increased with increasing carbon content. (Hereafter, the subscripts f and b denote f.c.c.…”

Matching crystal structures atom-to-atom

“…The principal strains for our new mechanism are -5.7%, 0% and 15,5%, whereas they would be -18,4%, 15,5% and 15,5% without the occurrence of slip planes (Bain distortion). This slipping process is often used in the context of the Phenomenological Theory of Martensitic Transformation [42][43][44][45][46] to explain the occurrence of striations along the (112) α ; our algorithm finds it naturally by minimizing distance.…”