材料学院青促会学术交流报告
报告人：悉尼大学 安祥海 博士
报告题目：Improving cyclic deformationresponses of nanostructuredmetallic materials via tuning thestacking fault energy and microstructures
地点：浙江大学玉泉校区曹光彪楼326会议室
时间：2017年05月26日（星期五） 14:30
邀请人：秦发祥
材料学院青年教师发展促进会承办
Abstract： With respect to the perspectiveengineering applications of nanostructured (NS) metallic materials, apart fromthe strength and ductility under monotonic loading, their cyclic deformationresponse is another essentially crucial concern owning to safety issues.Compared with their CG references, NS materials generally exhibit enhancedhigh-cycle fatigue (HCF) and decreased low-cycle fatigue (LCF) properties inthe light of the dependence of fatigue lives on the stress and strainamplitudes, respectively. Our recent investigations revealed that prominentimprovement of the LCF lives and HCF strengths, especially fatigue endurancelimits, of NS metals and alloys, can be simultaneously achieved with decreasingtheir stacking fault energy (SFE). These upgraded fatigue performances withlowering the SFE in NS materials can be attributed not only to the simultaneousincrease of their monotonic strength and ductility in macroscale, but also tothe crucially decreased cyclic softening behavior in terms of grain coarseningand shear banding in microscale. In addition, the dominant fatigue damagemicro-mechanism was also transformed inherently from extensive grain boundary(GB) migration to other local GB activities such as atom shufflingor GBsliding/rotation with the reduction of the SFE. Owing to the limitation oftheir intrinsic fatigue mechanisms, thefatigue endurance limits of NS metals and alloys cannot always acquireappreciable improvement with their monotonic strengths. However, tuning themicrostructures to harvest recrystallized nanostructures can significantlyenhance the fatigue strength of NS materials despite the lower tensilestrength. These results enable us to timely exploit the knowledge of fatiguebehavior of NS metallic materials, which is important both scientifically, forthe in-depth comprehension of their deformation behavior, and technologically,for assessing their service utilities in safety-critical structural components,and also open up promising venues for materials design to possess optimalmechanical properties.
BriefBio： Xianghai Anreceived his PhD degree in Materials Fatigue and Fracture Division, ShenyangNational Laboratory for Materials Sciences, Institute of Metal Research,Chinese Academy of Sciences.After receiving PhD degree, he joined the School of Aerospace,Mechatronic and Mechanical Engineering at The University of Sydney as aresearch fellow, then DVCR research fellow supported by University and iscurrently a DECRA fellow supported by Australia ARC. He was also conferred onthe Alexander von Humboldt Fellowship by Humboldt Foundation in Germany.
Dr. Xianghai An’sresearch mainly focuses on understanding the microstructures, deformationmechanisms, and mechanical behavior of advanced metallic materials by recourseto extensive microscopy characterization and mechanical testing. Up to date,more than 40 papers with citation and h-index of 990 and 18 (Google Scholar),respectively, have been published in top journals including Nano letters, Acta Materialia, Scripta Materialia, andApplied Physics Letters.
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