热暴露及表面氧化对γ-TiAl合金疲劳性能的影响  

Effects of Thermal Exposure and Oxidation on Fatigue Behavior of Gamma-based Titanium Aluminide Alloy

作　　者：黄甦 黄泽文[1] 胡伟[1] 

机构地区：[1]西南交通大学材料学院,四川成都610031

出　　处：《热加工工艺》2014年第8期61-65,共5页Hot Working Technology

基　　金：国家自然科学基金资助项目(51271154)

摘　　要：研究了全片层组织的中等强度γ-TiAl合金Ti-45Al-2Mn-2Nb-0.8TiB2在热暴露+表面氧化10000 h以后,4种加工表面与高频疲劳行为的定量关系。结果表明:在该TiAl合金的疲劳过程中当经历长时间热暴露+氧化后,相对于热暴露之前,该合金的疲劳强度有增有降,依表面加工方式而定。表面质量差的线切割样品以及表面无压应力的电解抛光样品,出现"热暴露+氧化增强"的现象,这表明大气热暴露导致的应力弛豫现象带来的有利效果大于表层氧化产生的不利效果。热暴露+氧化对喷丸样品有明显不利效果,热暴露引起的应力弛豫导致喷丸样品表面压应力降低,层厚减薄,氧化引起表面疏松,引入了缺陷。A moderately strengthened fully lamellar ingot TiA1 alloy Ti-45A1-2Mn-2Nb-0.8 vol% TiB2 in a exposure condition （exposure＋oxidation at 700℃ for 10000 h） was studied to assess the effects of four types of surface manufactured on high cycle fatigue behavior. The results show that the alloy after thermal exposure＋surface oxidation at 700℃ for 10000 h shows either higher or lower fatigue strength than the same type of surface condition without exposure. The EDM surface and electropolished surface without compressive-stressed layer show a ＂thermal exposure＋oxidation strengthening＂ phenomenon. The results show that the beneficial effects of the stress relaxation caused by the long-term isothermal exposure in air outweigh the harmful effects of oxidation layers formed on these surface. However, the thermal exposure＋oxidation is found to be harmful to shot-peening specimens. This is because the compressive stresses on shot-peening surface are released and the surface layer becomes deteriorated and loose during thermal exposure＋oxidation.

关 键 词：Γ-TIAL合金 疲劳 热暴露 表面氧化 

分 类 号：TG111.8[金属学及工艺—物理冶金]