Fe元素对TA15钛合金显微组织和力学性能的影响

Effects of Fe on the Microstructures and Mechanical Properties of TA15 Titanium Alloy

研究了添加少量的Fe元素(<0.2%,质量分数)对TA15钛合金力学性能的影响。对比分析了未添加Fe元素的TA15合金和添加了0.20%的Fe元素的TA15合金(TA15-Fe)的拉伸性能、冲击韧性、断裂韧性、高温持久性能,并利用能谱仪测试了合金中主要元素的分布情况。研究结果表明:添加少量Fe元素对TA15钛合金的显微组织没有明显影响;两种合金的冲击韧性和室温、高温断裂韧性也基本无差异;而TA15-Fe钛合金的室温、高温抗拉强度较TA15钛合金提高约15 MPa,但在500℃下的持久寿命显著降低。这是由于Fe元素在β相内富集,起到固溶强化作用,从而提高了合金的抗拉强度;到了500℃Fe元素扩散迅速,从而加速了基体内原子和空位的运动,导致持久过程中位错攀移阻力下降,因此持久寿命降低。

This paper studied the influences of small amounts of Fe elements （ less than 0. 2 w/% ） on mechanical properties of TA15 titanium alloy. The concentrations of elements were tested using the energy spectrum. The tensile properties, impact toughness, fracture toughness and high temperature lasting performance of TA15 （0.05% Fe） and TA15-Fe （0. 20% Fe） alloys were analyzed. The results show that the change of Fe content has no apparent influence on microstructures. There is basically no difference in both the impact toughness and fracture toughness at room temperature between the two kinds of alloys. Tensile strength of TA15-Fe alloy is increased by about 15 MPa, however, the high temperature stress rupture life greatly reduces. From the observed facts it is known that Fe element enriched in beta phase and has solid solution strengthening effect on the alloy. At 500 %, the diffusion rates of atoms and vacancies are accelerated by the addition of Fe content, leading to easier climbing of dislocations in the process of enduring, so that lasting life of TA15-Fe is reduced.