Influence of temperature on microstructure parameters and microhardness of dispersion-hardened V–Cr–Zr–W alloy after deformation by torsion under pressure

Study of microstructure transformation and microhardness changes of dispersion-hardened V–Cr–Zr–W alloy after severe plastic deformation by torsion on Bridgman anvils and subsequent heat treatments was conducted. Basic stages of relaxation processes were revealed: at 800°C recovery processes take place and primary recrystallization begins; at 900°C primary recrystallization intensifies; in range of 950–1050°C collective recrystallization processes activate; at 1200°C secondary recrystallization starts. Microhardness measurement and comparison of its values with structural states features were conducted. Strengthening mechanisms and their contribution at various stages of defect substructure relaxation are discussed. It is shown that increase of thermal stability of V–Cr–Zr–W alloy microstructure is a consequence of the formation of high density of thermally stable Zr (O–N–C)-based nanoparticles