Excellent mechanical properties of a Ti-based alloy via optimizing grain boundary α phase

Abstract

In this paper, the continuous grain boundary α phase of a Ti-based alloy is optimized by the combined process of deformation and heat treatment, the equiaxial discontinuous grain boundary α phase is obtained, and the ductility is greatly improved while the strength still keep high (strength of 1280 MPa and elongation of 10 %). Firstly, continuous grain boundary α phase is obtained by solid solution-short time aging, then the continuous grain boundary α phase is sheared and broken by 30 % hot rolling deformation, and finally recrystallized by recrystallization annealing, the near duplex microstructure with equiaxial grain boundary α phase and lamellar secondary α phase is obtained, and the comprehensive mechanical properties of this near duplex microstructure are obviously better than that of the traditional lamellar, duplex or equiaxial microstructure. This paper provides a new idea for strengthening and toughening design of metal materials and thus should be of interest.