Researching structure heterogeneity of VT41 titanium alloy billet after thermomechanical treatment

Abstract

The heterogeneity of the titanium VT41 structural state after hot upset test was investigated by analytical methods of optical and scanning microscopy. Vickers microhardness measurements were performed to estimate the mechanical properties. The analysis of the distribution of deformation and the features of the formation of the structural components of the specimen. Globular grains were deformed by the mechanism of intergranular slipping. β-grains and α-plates made the greatest contribution to plastic deformation. Lamellar grains of α-phase in the zone of localization of deformation undergo recrystallization. The dimensions of the zone in which the recrystallization occurred, coincide with the zone of localization of the deformation, estimated by macrostructure. When tempering the billet, the β-phase in the center of the sample breaks down into α-plates, and in the near-surface areas into smaller grains, probably representing needle-like β-titanium martensite. A decrease in microhardness in the central regions may be due both to recrystallization and to the fact that martensite has been quenched in the surface layers.