On the influence of (α↔σ)-transformation on Fe-Cr-Co-Mo alloy structure

The field of (α↔α+σ) transformation in the Fe-30%Cr-15%Co-3%Mo alloy and the influence of σ-phase amount on single-phase α-state structure were investigated. On σ-phase dissolution in the alloy structure the redistribution of crystal defects takes place and promotes formation of substructure and large-angle boundaries of centers of recrystallization. Critical quantity of σ-phase (around 65%) at the largest grain size results in a growth of the former less deformed grains. A higher σ-phase content initiates the mechanism of recrystallization with nucleation and growth of new grains. 3 refs., 4 figs