Mo对Ti-Mo系合金显微组织的影响及其强化效应

Influence of Mo on Microstructure of Ti-Mo Alloys and Strengthening Effects

对不同Mo含量β单相区锻造的Ti-Mo合金在相变点以上进行固溶处理,然后对合金进行显微组织分析和力学性能测试。结果表明:Ti-1Mo合金和Ti-2Mo合金主要由等轴的α相组成,Ti-4Mo合金主要由针状六方马氏体α′相和原始β晶界组成,当合金Mo含量超过10%(质量分数)时,合金主要由等轴的β相组成。晶粒尺寸统计结果显示:晶粒尺寸与固溶时间呈指数关系;在固溶时间一定的条件下,晶粒尺寸随固溶温度的升高而增大,随合金中Mo含量的增加而明显减小。另外Ti-Mo合金的强度随晶粒尺寸的减小而提高,但合金的塑性变化不大,最后对影响合金强化的机理进行了探讨。

The effects of Mo on the microstructure and mechanical properties of a series of β forged Ti- Mo alloys at different solution treatment temperatures and time were studied with an emphasis on the relationship between β-grain size and mechanical properties. The results show that the microstructure and crystal structure of solution treated alloys are sensitive to Mo contents. Ti-lMo and Ti-2Mo alloys are composed of equiaxed α phase. Ti-4Mo alloy is composed of acieular α＇ and β grain boundary. When Mo content increases to 10% （mass fraction） or higher, the retained β phase becomes the only dominant phase. The β-grain size is not only relative to solution treatment temperatures and time, but also relative to Mo contents from statistical results. It indicates that the β-grain size increases with the increasing of solution treatment temperature and decreases with the addition of Mo contents under the same solution time. The strength of the alloys increases with the decreasing of grain size, but the plasticity of the alloys changes little. The mechanism of strengthening was also analyzed.