Atomistic study of inverse size effect induced by interfacial plasticity in pearlitic multi-principal element alloy  

作　　者：Chen Yang Qiao-Sheng Xia Cun-Hong Yin Dong-Peng Hua 

机构地区：[1]College of Mechanical Engineering,Guizhou University,Guiyang 550025,China [2]Key Laboratory of Advanced Manufacturing Technology,Ministry of Education,Guizhou University,Guiyang 550025,China [3]State Key Laboratory of Solidification Processing,Center of Advanced Lubrication and Seal Materials,Northwestern Polytechnical University,Xi'an 710072,China

出　　处：《Rare Metals》2024年第7期3341-3355,共15页稀有金属（英文版）

基　　金：financially supported by the Natural Science Foundation of China (Nos.52361013 and 52001082);Guizhou Provincial Basic Research Program (Natural Science) (No. ZK [2022] general 137);Talent Project of Guizhou University and Natural Science Foundation of Guizhou University (No.202201);Open Foundation of Key Laboratory of Advanced Manufacturing Technology Foundation (No.GZUAMT2022KF[01])。

摘　　要：Owing to the fine nano-laminated structure,the pearlitic multi-principal element alloy(PMPEA) exhibits excellent mechanical and tribological properties.However,the incomplete understanding of the size effect of its lamella thickness and the unclear understanding of the plasticity-interface interaction mechanism limit further optimization of PMPEAs.In this study,the FeCoNi/Ni_3Ti interface-mediated plastic deformation behavior in PMPEA and the variation of mechanical and tribological properties with lamella thickness within the nanoscale range using molecular dynamics(MD) simulation were explored.The results indicate that the mechanical and tribological properties of the PMPEA with lamella thicknesses below 10 nm have a significant inverse size effect,i.e.,the smaller the lamella thickness,the weaker the properties.This is because the plastic carrier-interface interaction mechanism changes from a strengthening mechanism that hinders dislocations to a weakening mechanism that promotes dislocations with the decreases in the lamella thickness,and the weakening effect becomes more pronounced as the lamella thickness decreases and the number of interfaces increases.In particular,the deformation behavior of Ni_3Ti lamellae changes from crystal-like to amorphous-like with decreasing lamella.Moreover,in the sample with larger lamella thickness,the occurrence of hierarchical slips in the body-centered cubic(BCC) phase due to the multiprincipal elements effect can better alleviate the stress concentration caused by the dislocation accumulation at the interface,so that the phase interface exhibits outstanding load-bearing effects.And the dislocation pattern in BCC phase shows a firm high-density cell,which makes the substrate exhibit a stable tribological response.

关 键 词：Multi-principal element alloy Nano-laminated structure Molecular dynamics simulation Nanoindentation and nanoscratch 

分 类 号：TG132[一般工业技术—材料科学与工程]