摘要
The refractory high entropy alloys(RHEAs)containing disordered body-centered cubic(BCC)and ordered BCC(B2)structures often exhibit high strength but low ductility at room temperature,even in the compressive tests.In this study,(Ta_(25-x)Nb_(25)Zr_(25)Ti_(25+x))95Al_(5)(x=0,5,10)RHEAs are fabricated to investigate the compositional dependence of the microstructures and mechanical properties.All the three alloys exhibit a single BCC structure at the as-cast and solution-treated states,while the basket weave-like microstructures consisting of cuboidal and strip-like phases are formed after aging at 600°C.The microstructure of the aged alloys is sensitive to the compositions:only disordered BCC1+BCC2 dual phases are observed in the(Ta_(25)Nb_(25)Zr_(25)Ti_(25))_(95)Al_(5)alloy;additional B2 phases are formed by replacing 5 at%Ta with Ti;a complex microstructure containing BCC1+BCC2+B2+Omega phases are identified in the(Ta_(15)Nb_(25)Zr_(25)Ti_(35))_(95)Al_(5)alloy.Although replacing Ta with Ti results in a reduction of compressive yield strength from 1762 to 1243 MPa,the fracture strain is greatly enhanced from 7.3 to 44.3%,indicating that the strength-ductility balance can be tuned to a large extent in this RHEA system.
基金
financially supported by the National Natural Science Foundation of China (Grant No. 11905008)
作者简介
Dr.Ke Jin,received his B.S.degree in Physics from Peking University in 2010,M.S.degree in Materials Science and Engineering from the University of Florida in 2011,and Ph.D.degree in Materials Science and Engineering from the University of Tennessee in 2015.After three-year postdoctoral research at the Oak Ridge National Laboratory,he is currently a professor at Beijing Institute of Technology.His research interests include the development of novel structural materials,e.g.high entropy alloys,for advanced nuclear reactors and ion irradiation effects in materials.,jinke@bit.edu.cn。
