マルテンサイト逆変態を活用した鉄鋼材料の力学特性向上

抄録

Martensitic reversion from bcc-martensite to fcc-austenite is an important phase transformation to improve mechanical properties of steels remarkably as well as other phase transformations. However, few studies have undertaken to investigate the martensitic reversion, because it hardly occurs in carbon steels. In the present overview, some characteristics of the martensitic reversion were explained briefly with reference to the previous studies, and a couple of applications of microstructural control for high alloy steels using the martensitic reversion were introduced. Furthermore, a novel heat treatment through the martensitic reversion to improve strength and toughness of low alloy martensitic steel was proposed.

Fig. 7 EBSD data, (a-d) inverse pole figure, (e) phase and (f-h) kernel average misorientation maps, showing recrystallization of martensitic reversed austenite by bulge mechanism in Fe-32％Ni-5％Co cast alloy, which were after (a, e) sub-zero treatment at 77 K and annealing at (b, f) 923, (c, g) 1073 and (d, h) 1173 K.