摘要
钛合金具有比强度高、抗疲劳性能好和耐腐蚀性优异等特点,已广泛应用于航空、能源、化工和医药等领域,特别适合于制造航空发动机的压气机盘、风扇盘和叶片等部件.然而,在飞机运行过程中航空发动机部件通常受保载疲劳的影响,这会显著降低部件的使用寿命并威胁到航空安全,因此研究钛合金的保载疲劳行为至关重要.本文研究了片层组织钛合金(α板条和β板条交替排列)在室温保载疲劳过程中的裂纹形核过程.集束中的α板条和β板条变形不匹配,α板条中的位错滑移容易造成在片层界面处产生大量残余位错.界面残余位错引起的局部拉应力促进集束中微孔的形成和连接,从而产生保载疲劳裂纹.这项工作提供了片层组织钛合金在保载疲劳过程中的裂纹形核机制,同时也有助于认识片层材料的开裂行为,对材料的组织发展有指导意义.
Titanium alloys have been widely used in aerospace,energy,chemical and medical industries,especially in aero-engines,attributed to their high specific strength,good fatigue performance and excellent corrosion resistance.However,aero-engine components are usually subjected to dwell fatigue during aircraft operation,which significantly deteriorates the fatigue life and easily threatens aviation safety.Thus it is essential to understand the dwell fatigue behavior of titanium alloys.In this work,the formation me-chanism of cracks in titanium alloys with lamellar micro-structure has been investigated on low-cycle dwell fatigue.The deformation ofαandβlaths does not match in colonies,so the dislocation slip ofα-Ti gives rise to extensive residual dis-location pile-up atα/βinterfaces.The local tensile stress generated by residual dislocations is high and thus promotes the formation and coalescence of cavities in colonies,resulting in dwell fatigue cracks.These results provide insights on the formation of cracks in titanium alloy with lamellar micro-structure under dwell fatigue,and they also give implications on the cracking of materials with lamellar microstructures in general.
作者
周志春
江彬彬
邱建科
张陵磊
雷家峰
杨锐
杜奎
Zhichun Zhou;Binbin Jiang;Jianke Qiu;Linglei Zhang;Jiafeng Lei;Rui Yang;Kui Du(Shenyang National Laboratory for Materials Science,Institute of Metal Research,Chinese Academy of Sciences,Shenyang 110016,China;School of Materials Science and Engineering,University of Science and Technology of China,Shenyang 110016,China;Shi-Changxu Innovation Center for Advanced Materials,Institute of Metal Research,Chinese Academy of Sciences,Shenyang 110016,China)
基金
supported by the National Natural Science Foundation of China(91960202,52171020,51701219)
the CAS Project for Young Scientists in Basic Research(YSBR-025)
the Youth Innovation Promotion Association CAS(2022188)
the National Key R&D Program of China(2021YFC2800503 and 2022YFB3708300)。
