Effect of alloy addition on structure and properties of cast Ti-7.5%Mo alloy

摘要

The present work is a study of the effect of 1 wt％ addition of a series of alloying elements on the structure and properties of a Ti-7.5％ Mo system. The results indicate that the phase/crystal structure, microstructure and mechanical properties of Ti-7.5％ Mo alloy can be significantly changed by small amounts of alloy addition. Ti-7.5％ Mo is a typical orthorhombicα" phase alloy. When 1 wt％ zirconia or niobium is added, its fine, acicular martensitic structure of α" phase remains, microhardness increases 25-29％, bending strength increases 13-21％, while modulus only slightly increases. When chromium is added, a significant amount of equiaxed, P phase is retained, and microhardness, strength and modulus all largely increase. When iron is added, the equiaxedβphase becomes the only dominant phase, and its hardness, strength and modulus all become the highest among all titanium alloys in this study. The cast Ti-7.5％Mo-1％Nb and Ti-7.5％Mo-1％ Zr alloys exhibit higher strengths than do Ti-7.5％Mo, Ti-15％Mo, Ti-13％Nb-13％Zr, c.p. (commercially pure) Ti and Ti-6％Al4％V, while maintaining their low moduli.