高温钛台金中微量元素的作用机理

Studies On Function Of Trace Elements In High Temperature Titanium Alloy

本文以两种高温钛合金为基体材料,运用俄歇能谱仪、分析电镜研究微量元素硼、铈在高温合金中的分布及其对其它元素分配的影响;研究硼、铈对高温合金的热稳定性、蠕变性能等高温性能的影响。结果表明;超过析出硼化物含量的硼抑制铈在界面的偏析;铈在界面的偏析促进硅在界面的偏析,并抑制硅化物的生成;硼、铈复合加入使硅在初生α相中含量增加,使两相中铝、钼扩散充分。硼、铈加入引起的这些微观结构变化增强了固溶强化效果,抑制α相中Ti_3X析出,提高了材料的热稳定性;改变层错能,强化活动位错的钉扎作用及延缓空洞长大,提高了材料的蠕变性能。因此,研究硼、铈加入后的微观结构,对探讨硼、铈对高温性能影响的机理具有很重要的意义。

This paper studies the distribution of two trace elements B and Ce in two series of high temperature titanium alloys and the effect of the trace elements on the distribution cf other elements using AES and TEM, and also en the elevated temperature properties such as the stability and creep strength of alloys. The result shows that the excess B restrains the formation of cerous compound on grain bourdaries,and the interfacial segregation of Ce promotes Si atom to concentrated at the grain bourdaries,and thus restrains the formation of silicide. It also indicates that the combined addition cf optimiged content of B and Ce increases the content cf Si in primary 2 phase,making the diffusion of Al. Mo in a/3 phase more completely. The change in microstruct-ure caused by the additions of B and Ce reinfcrces the effect of solid solution strengthening, and restrains the precipitaton cf Ti,X in a phase, and in ture reinforces the elevated temperature stability. It also results in the reducing of the stacking fault energy, reinforcing of the nailling effect to the motionable dislocations,and slowing down of the growth of cavities, there fore improves the creep property.