Al-Cr-Nb-Ti-Zr共晶难熔高熵合金高温摩擦磨损性能研究  

Tribological Properties of Al-Cr-Nb-Ti-Zr Eutectic Refractory High Entropy Alloy at High Temperature

作　　者：胡明川 杜银 裴旭辉 王瀚铭 王海丰[1] HU Mingchuan;DU Yin;PEI Xuhui;WANG Hanming;WANG Haifeng(Center of Advanced Lubrication and Seal Materials,State Key Laboratory of Solidification Processing,Northwestern Polytechnical University,Shaanxi Xi’an 710072,China)

机构地区：[1]西北工业大学凝固技术国家重点实验室先进润滑与密封材料研究中心,陕西西安710072

出　　处：《摩擦学学报（中英文）》2024年第5期609-621,共13页Tribology

基　　金：国家自然科学基金项目(51975474);凝固技术国家重点实验室自主研究课题资助项目(2023-BJ-04);中国博士后科学基金项目(2023M73284);中央高校基本科研业务费项目(3102019JC001)资助。

摘　　要：通过非自耗真空电弧熔炼制备了Al_(15+x)Cr_(20)Nb_(15)Ti_(40-x)Zr_(10)(x=0、13)共晶难熔高熵合金,并探究了Al和Ti元素含量变化对Al_(15+x)Cr_(20)Nb_(15)Ti_(40-x)Zr_(10)共晶难熔高熵合金相结构、微观组织、显微硬度与高温摩擦性能的影响规律.结果表明:2种合金相结构相同,均由富含Nb和Ti的B2相与富含Cr和Zr的C14 Laves相组成;但随着Al含量的增大,合金铸态组织发生了从亚共晶(初生B2相+B2/Laves相共晶相,x=0)到共晶(B2/Laves相共晶相,x=13)的转变,同时伴随着合金显微硬度的提高,并且在宽温域下的摩擦性能有所改善.随着摩擦试验温度的升高,2种合金的磨损机制均从磨粒磨损逐渐转变为以氧化磨损为主,且磨损率均呈现出逐渐降低的趋势.不同温度下摩擦试验发现完全共晶合金Al28Cr20Nb15Ti27Zr10表现出更好的耐磨性,这是由于完全共晶合金更高的硬度以及在高温下的氧化摩擦层含有更大比例的Al2O3,从而摩擦层更为致密.Recently,a series of new refractory high entropy alloys with eutectic structure have been prepared by researchers through composition regulation,specifically the addition of elements such as Al and Cr.Refractory high entropy alloys produced by this new strategy exhibit superior structural stability and significantly improved resistance to high-temperature oxidation,as compared to their conventional counterparts.Besides,previous studies have reported that the tribological properties of high entropy alloys could be significantly enhanced by incorporating eutectic structures.Based on the above,the design strategy of these novel refractory high entropy alloys may offer a new approach to simultaneously address the problems of inadequate high temperature resistance to oxidation and wear in conventional refractory high entropy alloys.Therefore,it is necessary to further enrich the research on the high temperature wear behavior of these new refractory high entropy alloys.In this work,eutectic refractory high entropy alloy Al_(15+x)Cr_(20)Nb_(15)Ti_(40-x)Zr_(10)(x=0,13)were prepared by vacuum arc-melting.The effects of Al and Ti elements content changes on the phase structure,microstructure,microhardness were studied by XRD,SEM,EDS and nanoindentation.The high-temperature tribological properties of the eutectic refractory high entropy alloys Al_(15+x)Cr_(20)Nb_(15)Ti_(40-x)Zr_(10) were investigated by ball-on-disk machine,3D optical microscope,XPS and SEM.Based on the SEM and EDS results,these two alloys had the same phase structure and were composed of B2 phase rich in Nb and Ti and C14 Laves phase rich in Cr and Zr.SEM results showed that with the increase of Al content,the as-cast microstructure of the alloy underwent a transition from hypoeutectic(primary B2 phase+B2/Laves eutectic phase,x=0)to eutectic(B2/Laves eutectic phase,x=13),accompanied by the increase of the microhardness,the microhardness of Al15Cr20Nb15Ti40Zr10alloy was 558 HV and Al28Cr20Nb15Ti27Zr10alloy was 713 HV.One contributing factor to the increase

关 键 词：共晶难熔高熵合金 共晶组织 显微硬度 摩擦性能 磨损机制 

分 类 号：TH117.2[机械工程—机械设计及理论] TH145[一般工业技术—材料科学与工程]