NbMoTiVSi_(x)难熔高熵合金组织结构及力学性能  

Microstructure and Mechanical Properties of NbMoTiVSi_(x) Refractory High Entropy Alloy

作　　者：张炜 徐琴[4] 吴帅帅[2] 朱宝宏 郭胜利 Zhang Wei;Xu Qin;Wu Shuaishuai;Zhu Baohong;Guo Shengli(State Key Laboratory of Non-ferrous Metals and Processes,GRINM Group Co.,LTD.,Beijing 100088,China;GRIMAT Engineering Institute Co.,LTD.,Beijing 101407,China;General Research Institute for Nonferrous Metals,Beijing 100088,China;School of Mechanic and Electrical Engineering,Henan University of Technology,Zhengzhou 450001,China)

机构地区：[1]中国有研科技集团有限公司有色金属材料制备加工国家重点实验室,北京100088 [2]有研工程技术研究院有限公司,北京101407 [3]北京有色金属研究总院,北京100088 [4]河南工业大学机电工程学院,河南郑州450001

出　　处：《稀有金属》2023年第9期1204-1212,共9页Chinese Journal of Rare Metals

基　　金：国家自然科学基金青年项目(52001114)资助。

摘　　要：利用真空电弧熔炼技术制备了NbMoTiVSi_(x)(x=0,0.25,0.5)高熵合金,通过扫描电子显微镜(SEM)、透射电子显微镜(TEM)、X射线衍射仪(XRD)对NbMoTiVSi_(x)(x=0,0.25,0.5)高熵合金铸态和退火态的显微组织和相结构进行观察和分析,采用Instron3369型电子万能试验机和430SWD型硬度计对样品力学性能进行了表征。结果表明:NbMoTiV合金由单一体心立方(bcc)相构成,NbMoTiVSi_(0.25)合金和NbMoTiVSi_(0.5)合金为bcc+M_(5)Si_(3)(M=Nb,Mo,Ti,V)双相结构。1200℃保温24 h退火处理后,3种合金组织无明显变化:随着Si含量的增加,NbMoTiVSi_(x)(x=0,0.25,0.5)高熵合金的bcc相晶格常数增加,形成的M_(5)Si_(3)相形貌由板条状变为菊花状;硬度由HV 358.3升高到HV 660.7,抗压强度由1747MPa升高到2038 MPa,而压缩断裂应变则由30%降低到16%。断口形貌分析表明:NbMoTiVSi_(x)(x=0,0.25,0.5)高熵合金断口形貌呈河流状花样,NbMoTiVSi_(0.25)合金断口存在微裂纹和少量的韧窝,NbMoTiVSi_(0.5)合金断口形貌为大量的河流状花样、羽毛状花样、台阶以及裂纹;随着Si元素的添加,NbMoTiVSi_(x)(x=0,0.25,0.5)高熵合金的断裂机制由韧-脆混合断裂向准解理脆性断裂转变。With the rapid development of modern aerospace technology,the extreme environment has put forward more stringent requirements on the properties of alloys.Due to the structure and properties of traditional alloys cannot meet the special performance requirements,new materials are urgently needed.Ni-based superalloy,which is widely used in high temperature materials,but it is limited by its own melting point and service temperature is only 1100~1150℃.The high temperature service range of materials restricts the use of blades for gas turbine and high-temperature structural materials,High melting point metal elements have unique advantages because of their own properties,so it is expected to improve the service temperature range of high temperature structural materials by using high melting point metal elements.Three kinds of high entropy alloys NbMoTiVSi_(x)(x=0,0.25,0.5)were melted in a non-consumable vacuum arc furnace.All the ingots were melted five times to improve the uniformity.The diameter of the button ingot was about 120 mm,the height was about 40 mm,and the weight was about 1500 g.The actual composition of the alloy was determined by gravimetry(Nb)and Inductively coupled plasma-atomic emission spectrometry(Mo,Ti,V,Si).All the test and analysis samples were taken from the middle of the ingot with the size of 10 mm×10 mm×10 mm.The compression specimen size was Φ10 mm×15 mm.Before annealing,the samples were packaged in a vacuum quartz tube and the heat treatment system was to raise the temperature to 1200℃ with the furnace,keep the temperature for 24 h,and then cool with the furnace.D/max-RB X-ray diffractometer(XRD)was used to analyze the phase of the sample.The scanning speed was 5(°)·min^(-1),scanning angle was 20°~120°.Vickers hardness of 11points was measured by 430SWD hardness tester under 49.03N load,the loading time was 15 s.The composition ratio of corrosive agent was:NbMoTiV(HF∶HNO_(3)=1∶1),NbMoTiVSi_(0.25)(HF∶HNO_(3)∶H_(2)O=1∶1∶5)and NbMoTiVSi_(0.5)(HF∶HNO_(3)∶H_(2)O=1∶

关 键 词：难熔高熵合金 晶体结构 微观组织 力学性能 

分 类 号：TG139[一般工业技术—材料科学与工程]