CAJ | 학술논문

通过喷丸和电解抛光的方法处理Ti-44Al-5Nb-1W-1B(摩尔分数，%)合金，研究其在长期热暴露(10000 h,700℃)前后疲劳性能的变化。结果表明：在热暴露前，电解抛光处理比喷丸处理更能改善该合金的疲劳性能。经过长期热暴露后，两种表面处理样品的疲劳性能均出现不同程度的衰减，但电解抛光处理相对于喷丸处理能够更好地保持合金的疲劳性能。长期热暴露会导致合金表面发生氧化，合金内部发生“释氧脆化”和“B2+ω有序相生成脆化”，这3种变化均对合金的疲劳性能产生不利影响。表面氧化使得喷丸工艺所引入的表层残余压应力在长期热暴露时明显降低，这导致疲劳性能大幅度衰减。相对而言，电解抛光工艺使合金获得光滑平整无缺陷的表面，无明显应力集中，因此合金有较高的抵抗热暴露性能衰退的能力。
통과분환화전해포광적방법처리Ti-44Al-5Nb-1W-1B(마이분수，%)합금，연구기재장기열폭로(10000 h,700℃)전후피로성능적변화。결과표명：재열폭로전，전해포광처리비분환처리경능개선해합금적피로성능。경과장기열폭로후，량충표면처리양품적피로성능균출현불동정도적쇠감，단전해포광처리상대우분환처리능구경호지보지합금적피로성능。장기열폭로회도치합금표면발생양화，합금내부발생“석양취화”화“B2+ω유서상생성취화”，저3충변화균대합금적피로성능산생불리영향。표면양화사득분환공예소인입적표층잔여압응력재장기열폭로시명현강저，저도치피로성능대폭도쇠감。상대이언，전해포광공예사합금획득광활평정무결함적표면，무명현응력집중，인차합금유교고적저항열폭로성능쇠퇴적능력。
The Ti-44Al-5Nb-1W-1B(mole fraction, %) alloy was treated by two surface treatment processes of shot peening and electropolishing, the changes of the fatigue behavior of the alloy exposed at 700 ℃ in air for 10000 h was studied. The results show that the fatigue strength of electropolishing specimens is higher than that of shot peening specimens before exposure. The fatigue strengths of the alloys with both surface conditions reduce after long-term thermal exposure, but the electropolishing specimens can maintain the fatigue properties of the alloy better than the shot-peening specimens. Long-term thermal exposure can cause oxidation on the surface and“B2+ω-formation induced embrittlement” and “oxygen-release induced embrittlement” inside of the alloy. All the three types of changes are detrimental to the fatigue performance of the alloy. The residual compressive stresses introduced by shot peening are released during long-term thermal exposure owing to the oxidation, which leads to a significant deterioration of the fatigue properties. The electropolishing specimens have very smooth surface without defects and stress concentration, therefore, the electropolishing specimens are more capable of resisting the deterioration of the fatigue properties than shot peening specimens during long-term thermal exposure.