Microstructural evolution and oxidation inα/βtitanium alloy under fretting fatigue loading  

作　　者：Hanqing LIU Xiaohong SHAO Kai TAN Zhenjie TENG Yaohan DU Lang LI Qingyuan WANG Qiang CHEN 

机构地区：[1]Failure Mechanics and Engineering Disaster Prevention Key Laboratory of Sichuan Province,Sichuan University,Chengdu 610065,China [2]Department of Mechanical Engineering,Kyushu University,Fukuoka 819-0395,Japan [3]Shenyang National Laboratory for Materials Science,Institute of Metal Research,Chinese Academy of Sciences,Shenyang 110016,China [4]Institute of Physical Chemistry,University of Münster,Münster 48149,Germany

出　　处：《Friction》2023年第10期1906-1921,共16页摩擦（英文版）

基　　金：supported by the National Natural Science Foundation of China(Nos.11802145 and 12002226);Hanqing LIU acknowledges the support of JSPS Postdoctoral Fellowship(No.P20737)from the Japan Society for the Promotion of Science and 2021 Open Project of Failure Mechanics and Engineering Disaster Prevention,Key Lab of Sichuan Province(No.FMEDP202106),China.

摘　　要：Coupling effects of fretting wear and cyclic stress could result in significant fatigue strength degradation,thus potentially causing unanticipated catastrophic fractures.The underlying mechanism of microstructural evolutions caused by fretting wear is ambiguous,which obstructs the understanding of fretting fatigue issues,and is unable to guarantee the reliability of structures for long-term operation.Here,fretting wear studies were performed to understand the microstructural evolution and oxidation behavior of anα/βtitanium alloy up to 108 cycles.Contact surface degradation is mainly caused by surface oxidation and the generation of wear debris during fretting wear within the slip zone.The grain size in the topmost nanostructured layer could be refined to~40 nm.The grain refinement process involves the initial grain rotation,the formation of low angle grain boundary(LAGB;2°–5°),the in-situ increments of the misorientation angle,and the final subdivision,which have been unraveled to feature the evolution in dislocation morphologies from slip lines to tangles and arrays.The formation of hetero microstructures regarding the nonequilibrium high angle grain boundary(HAGB)and dislocation arrays gives rise to more oxygen diffusion pathways in the topmost nanostructured layer,thus resulting in the formation of cracking interface to separate the oxidation zone and the adjoining nanostructured domain driven by tribological fatigue stress.Eventually,it facilitates surface degradation and the formation of catastrophic fractures.

关 键 词：fretting wear oxygen pick-up dynamic recrystallization grain rotation low angle grain boundary(LAGB) grain refinement 

分 类 号：TG146.11[一般工业技术—材料科学与工程]