摘要
This study explored a multi-mechanism approach to improving the mechanical properties of a Co CrFe Mn Ni high-entropy alloy through non-equiatomic alloy design and processing.The alloy design ensures a single-phase face-centered cubic structure while lowering the stacking fault energy to encourage the formation of deformation twins and stacking faults by altering the equiatomic composition of the alloy.The processing strategy applied helped create a hierarchical grain size gradient microstructure with a high nanotwins population.This was achieved by means of rotationally accelerated shot peening(RASP).The non-equiatomic Co Cr Fe Mn Ni high-entropy alloy achieved a yield strength of 750 MPa,a tensile strength of 1050 MPa,and tensile uniform elongation of 27.5%.The toughness of the alloy was 2.53×10^(10)k J/m^(3),which is about 2 times that of the same alloy without the RASP treatment.The strength increase is attributed to the effects of grain boundary strengthening,dislocation strengthening,twin strengthening,and hetero-deformation strengthening associated with the heterogeneous microstructure of the alloy.The concurrent occurrence of the multiple deformation mechanisms,i.e.,dislocation deformation,twining deformation and microband deformation,contributes to achieving a suitable strain hardening of the alloy that helps to prevent early necking and to assure steady plastic deformation for high toughness.
基金
the support of Basic Science Center Program for Multiphase Evolution in Hyper-gravity of the National Natural Science Foundation of China(51988101)
NSFC programs(52071003,91860202,11604006)
Beijing Municipal Education Commission Project(PXM2020014204000021 and PXM2019014204500032)
Beijing Outstanding Young Scientists Projects(BJJWZYJH01201910005018)
Beijing Natural Science Foundation(Z180014)
“111”project(DB18015)
the support by the Australian Research Council(DP190102990)to his work in this study。
作者简介
Corresponding author:Shengcheng Mao,E-mail addresses:scmao@bjut.edu.cn;Corresponding author:Yinong Liu,E-mail addresses:yinong.liu@uwa.edu.au;Corresponding author:Xiaodong Han,E-mail addresses:xdhan@bjut.edu.cn。
