Mo 含量对粉末冶金 Ti-Mo 合金组织与力学性能的影响

Six kinds of Ti-Mo alloys with different Mo contents (mass fractions) were prepared by cold isostatic pressing followed by atmospheric pressure sintering. The effects of Mo content on microstructure and mechanical properties of the alloy were investigated, as well as the related mechanism. The results show that Ti-Mo alloys with uniform composition and relative density up to 99.26% can be prepared by powder metallurgy. With the increase of the Mo content, the relative density of powder metallurgical Ti-Mo alloys decreases gradually, and the volume fraction of β phase increases gradually. When the Mo content reaches 30%, the alloy is pure β phase. The acicular α phase, lamellar α phase, and grain boundary α phase disappear successively with the increase of Mo content. The quasi-static compressive yield strength and microhardness of the Ti-Mo alloys increase first and then decrease with the increase of Mo content, while the variation tendency of the critical fracture strain is on the contrary. The alloys with high Mo content exhibit excellent compressive plasticity. The acicular α phase is the most important factor in affecting the strength and plasticity of alloys. With the increase of the volume fraction of acicular α phase,the strength increases but the plasticity decreases. In addition, the higher the content of β phase with low hardness and body-centered cubic structure, the higher the plasticity of Ti-Mo alloys, but the strength decreases.