文献类型：期刊文献

英文题名：Fatigue curve of microscale single-crystal copper: An in situ SEM tension-compression study

作者：Yan, Yabin[1,2];Sumigawa, Takashi[2];Wang, Xiaoyuan[1];Chen, Wufan[2,3];Xuan, Fuzhen[1];Kitamura, Takayuki[2]

机构：[1]East China Univ Sci & Technol, Minist Educ, Key Lab Pressure Syst & Safety, Shanghai 200237, Peoples R China;[2]Kyoto Univ, Dept Mech Engn & Sci, Nishikyo Ku, Kyoto 6158540, Japan;[3]Zhejiang Univ, Sch Aeronaut & Astronaut, Hangzhou 310058, Peoples R China

年份：2020

卷号：171

外文期刊名：INTERNATIONAL JOURNAL OF MECHANICAL SCIENCES

收录：;EI(收录号：20195207901954);WOS:【SCI-EXPANDED(收录号:WOS:000525417400001)】；

基金：This work was supported by National Natural Science Foundation of China (grant nos. 51835003, 11602252), Natural Science Foundation of Shanghai (grant no. 19ZR1413200), Fundamental Research Funds for the Central Universities (grant no. 50321071915017), and JSPS KAKENHI grant numbers 18H03753, 18K18807, 18H05241.

语种：英文

外文关键词：Fatigue curve; Microscale; In situ experiments; Single-crystal copper; Size effect

摘要：A series of quantitative in situ tension-compression fatigue experiments in SEM are performed to investigate the fatigue curve of microscale single-crystal copper specimens with a test part of 1 x 1 x 2 mu m under various strain amplitudes. The variation of resolved shear stress on the primary slip plane (tau(B4)) and the corresponding evolution of crystallographic slips in each cycle are analyzed and in situ observed, respectively. The variation of tau(B4) during fatigue shows that, (i) the variation of tau(B4) clearly includes the early stage, the saturation stage, and the final fracture of the specimen; (ii) apparent cyclic hardening and softening appear in the early stage of all specimens; (iii) tau(B4) shows a strain-dependent variation in the saturation stage. Continuous cyclic softening and secondary cyclic hardening occur in specimens with relatively higher strain, while only slight cyclic hardening emerges in the specimen with the minimum strain. Based on in situ SEM observations, the variation trend of tau(B4) is interpreted from the evolution of geometrical characteristics of slip traces. Finally, we obtain the fatigue curve of microscale single-crystal coppers. The fatigue life is apparently dependent on the strain amplitude, while insensitive to the frequency of cyclic loading. Moreover, the fatigue lives of microscale single-crystal Cu are much shorter than those of bulks, indicating a significant size effect. The difference in fatigue lives of microscale and bulk ones reduces from about 360 to only 7 times with the decrease of applied strain, revealing the strain-dependence of size effect of fatigue life for microscale single-crystal coppers.