Abstract
While considerable effort is made to understand the solid solution strengthening on the deformation behavior of high-entropy alloys(HEAs),relatively little attention is paid to the role of microstructural interfaces,especially twin boundaries(TBs),on the strain-rate sensitivity(SRS)of them.To address this,we have conducted micropillar compression experiments on single-,bi-,and twinned-crystals of CoCr-FeNi HEA and compared the results with those obtained with uniaxial tensile and compression tests on polycrystalline bulk samples.Results show that SRS,as well as the yield strength and plastic flow behav-ior,in single crystals are orientation dependent due to the differences in the maximum Schmid factors.While the high-angle grain boundaries arrest dislocation motion,TBs allow for dislocation transmission through them,which result in distinct mechanical responses.While the bi-crystal's deformation behav-ior is controlled by the'hard'grain,twinned crystals exhibit an'averaged'response.The large diversity of the reported SRS values in face centered cubic HEAs could be due to the varying fractions and thus contributions of annealing twins in the tested samples.
基金项目
Nanyang Technological University was supported by Agency for Science,Technology and Research(A*STAR)of Singa-pore via the Struct(A18B1b0061)
Hanyang University was supported by the NRF grants(2020R1A2B5B01001446)
Hanyang University was supported by the NRF grants(2020R1A5A6017701)
NETL
NSTL
维普
万方数据