摘要
采用真空电弧炉制备了Al_(0.3)CoCrFeNiNb_(x)(x为摩尔比,x=0,0.1,0.3,0.5,0.7,1.0)高熵合金棒材,用X射线衍射(XRD)、光学显微镜(OM)、扫描电镜(SEM)、能谱仪(EDS)、显微维氏硬度计和万能试验机对合金的微观组织和性能进行了研究。结果表明,Al_(0.3)CoCrFeNi合金的微观组织为单相面心立方(fcc);添加Nb后,合金由fcc相和Laves相组成,并随着Nb含量的增加,Laves相体积分数逐渐增多;至Al_(0.3)CoCrFeNiNb_(1.0)时,基体相从fcc相变为Laves相。Al_(0.3)CoCrFeNiNbx合金组织随Nb含量变化经历了亚共晶到过共晶的转变,同时衍射峰(111)fcc先向小角度移动后向大角度移动,晶格常数先增大后减小。Nb元素的增加可以有效提高Al_(0.3)CoCrFeNiNb_(x)合金的强度和硬度,硬度呈近似线性增加,从Al_(0.3)CoCrFeNi合金的HV152提高至Al_(0.3)CoCrFeNiNb_(1.0)合金的HV 745,提高了390%;Al_(0.3)CoCrFeNi合金和Al_(0.3)CoCrFeNiNb_(0.1)合金呈现出优异的压缩塑性(不断裂);随着Nb含量的继续增加,Al_(0.3)CoCrFeNiNb_(x)合金的抗压强度先提高后降低,而塑性降低。Al_(0.3)CoCrFeNiNb_(0.5)合金具有最优的综合力学性能,其抗压强度和维氏硬度分别为2397 MPa和HV 613。
High entropy alloys have broken the traditional alloy design concept and expanded the research fields.Due to the interaction between the multi-principal component atoms,high entropy alloys exhibit excellent properties,such as high strength,hardness and wear resistance,good corrosion resistance and oxidation resistance,which has a diversified industrial application prospect.Compared with conventional alloys,the microstructure of high entropy alloys exhibits single face-centered cubic(fcc)phase,single bodycentered cubic(bcc)phase or dual phases(fcc+bcc).Al-Co-Cr-Fe-Ni system is a relatively mature system for researchers at home and abroad.The phase composition of Alx CoCrFeNi alloy changes from single phase fcc,dual phase and single-phase bcc with increasing Al content.Among them,Al_(0.3)CoCrFeNi alloy with single phase fcc exhibit good plasticity and corrosion resistance,but low hardness.The negative mixing enthalpy between Nb and other elements and maximum atomic size in Al_(0.3)CoCrFeNiNb can result in strong precipitation strengthening or eutectic structure.Therefore,Al_(0.3)CoCrFeNiNb_(x)(mole ratio,x=0,0.1,0.3,0.5,0.7,1.0)high entropy alloy rods were prepared by vacuum arc melting.The microstructures were analyzed by X-ray diffraction(XRD),optical microscope(OM)and scanning electron microscope(SEM),and meanwhile the micro Vickers hardness and compression property at room temperature were tested.The effect of Nb content on the microstructure and properties of Al_(0.3)CoCrFeNi alloy were studied.Based on the research results,the optimal composition was obtained.The results showed that the microstructure of Al_(0.3)CoCrFeNi alloy was single phase fcc,and then transformed into eutectic structure composed of fcc and Laves phases after adding Nb.With increasing Nb content,the volume fraction of Laves phase increased.The lattice constant results showed that the diffraction peak the diffraction peak fcc(111)moved first to small angle,and then to large angle,and the lattice constant also first increased and then decre
作者
赵志豪
黄正华
陶平均
陈峰
闫志巧
Zhao Zhihao;Huang Zhenghua;Tao Pingjun;Chen Feng;Yan Zhiqiao(School of Materials and Energy,Guangdong University of Technology,Guangzhou 510006,China;Guangdong Provincial Key Laboratory of Metal Toughening Technology and Application,Guangdong-Hong Kong Joint Research and Development Center on Advanced Manufacturing Technology for Light Alloys,Institute of New Materials,Guangdong Academy of Sciences,Guangzhou 510650,China)
出处
《稀有金属》
EI
CAS
CSCD
北大核心
2024年第3期336-344,共9页
Chinese Journal of Rare Metals
基金
广东省科学院发展专项资金项目(2019GDASYL-0203002)
肇庆市重点领域研发计划“揭榜制”项目(2021C003)
中山市重大科技专项(2022A1006)资助。
关键词
高熵合金
Nb合金化
微观组织
力学性能
high entropy alloy
alloying of Nb
microstructure
mechanical property
