文献类型：期刊文献

英文题名：Uniaxial ratcheting behavior and microstructure evolution of 316H stainless steel under the random cyclic loads

作者：Zhou, Weitong[1];Zhou, Guo-Yan[1];Xiong, Xueyao[1];Xuan, Fuzhen[1];Tu, Shan -Tung[1]

机构：[1]East China Univ Sci & Technol, Key Lab Pressure Syst & Safety MOE, Shanghai 200237, Peoples R China

年份：2023

卷号：203

外文期刊名：MATERIALS CHARACTERIZATION

收录：;EI(收录号：20230130088);WOS:【SCI-EXPANDED(收录号:WOS:001042885200001)】；

基金：This work was financially supported by the National Natural Science Foundation of China (Grant No. 52075173) .

语种：英文

外文关键词：Thermal striping; Random cyclic load; Deformation twin; Twinning reduction

摘要：In this study, the Computational Fluid Dynamics (CFD)-Finite Element Method (CFD-FEM) were used to simulate the transient stress response of the structure surface under thermal striping environment, and a uniaxial random cyclic loading (RCL) method was used to reveal the mechanical properties and initial microstructure evolution of 316H austenitic stainless steel (SS) under random stress induced by thermal striping. The experimental results showed that 316H exhibited a lower saturation ratcheting strain rate at 334.44 MPa, along with stronger cyclic hardening effects and resistance to plastic accumulation at loading rate of 100 Hz. Random loading tests with different cycles were performed at & sigma;peak = 334.44 MPa and fRCL = 100 Hz, and ratcheted specimens were char-acterized to investigate the effect of the micro-mechanism on cyclic softening/hardening. The geometrically necessary dislocation (GND) density increases and then decreases with cyclic loading, which is mainly attributed to the deformation twin (DT) and multi-dislocation slip mechanisms. The deformation mechanism during the ratcheting cycle from 1000 to 3000 cycles is mainly dominated by the twinning reduction, where the dislocation migration accelerated the transformation from dislocation walls to subgrain boundaries; the twinning increase dominates from 3000 to 9000 cycles, where the subgrain boundary grew into boundaries with high angle misorientations.