激光熔化沉积AlCoCrFeNi_(2.5)高熵合金的组织与力学性能研究  

Investigation of Microstructures and Mechanical Properties of Laser-Melting-Deposited AlCoCrFeNi High Entropy Alloy

作　　者：黄留飞 孙耀宁[1] 季亚奇 吴昌贵 乐国敏[2] 刘学[2] 李晋锋[2] Huang Liufei;Sun Yaoning;Ji Yaqi;Wu Changgui;Le Guomin;Liu Xue;Li Jinfeng(School of Mechanical Engineering,Xinjiang University,Urumqi,Xinjiang 830047,China;Institute of Materials,China Academy of Engineering Physics,Mianyang,Sichuan 621907,China;College of Physics,Sichuan University,Chengdu,Sichuan 610064,China)

机构地区：[1]新疆大学机械工程学院,新疆乌鲁木齐830047 [2]中国工程物理研究院材料研究所,四川绵阳621907 [3]四川大学物理学院,四川成都610064

出　　处：《中国激光》2021年第6期97-104,共8页Chinese Journal of Lasers

基　　金：中国工程物理研究院院长基金(YZJJLX2019010);中国工程物理研究院创新基金(CX2019020);新疆维吾尔自治区高校科研计划(XJEDU2019I005)。

摘　　要：采用激光熔化沉积法制备AlCoCrFeNi_(2.5)高熵合金,通过X射线衍射仪、扫描电子显微镜、能谱仪、电子背散射衍射技术和力学拉伸测试研究合金的凝固组织、元素分布和力学性能。研究结果表明,通过激光熔化沉积法制备的AlCoCrFeNi_(2.5)高熵合金的微观组织为外延生长的柱状枝晶,其由一次和二次枝晶干处的面心立方(FCC)相与枝晶间隙处的体心立方(BCC)相组成。拉伸结果表明,在激光沉积方向,合金的抗拉强度达到1428 MPa,延伸率为25.8%。断口形貌显示出在FCC相区域观察到了大量的滑移轨迹,而位于枝晶间隙处的硬质BCC相能够有效阻碍滑移的扩展,使得FCC相中的位错密度进一步提高。拉伸变形过程中,合金内部组织中的FCC相与BCC相的耦合协同作用,可以促使AlCoCrFeNi_(2.5)高熵合金表现出优异的综合力学性能。Objective Recently,with the development of laser technology,increasingly complex components of high entropy alloy(HEA)can be prepared using laser three-dimensional(3 D)printing technology.However,HEA prepared using this method exhibit low strength and plasticity.Therefore,AlCoCrFeNi_(2.5) HEA with high plasticity is introduced in laser melting deposition(LMD)technology,which is a laser 3 D printing technology.Herein,the microstructure and mechanical properties of AlCoCrFeNi_(2.5) HEA prepared using LMD are studied.We aim to fabricate HEA with excellent mechanical properties using the laser 3 D forming method.Methods LMD has been developed to synthesize AlCoCrFeNi_(2.5) HEA.The laser process parameters are as follows:laser power,scanning speed,powder feeding speed,shielding gas flow rate,spot diameter,defocusing amount,and lifting amount are 700 W,400 mm/min,8 g/min,5 L/min,2 mm,11 mm,and 0.25 mm,respectively.The material used for LMD is AlCoCrFeNi_(2.5) high entropy prealloyed powder(sphericity≥90%),and the range of the alloy particle size measured using the laser particle size analyzer is 45-105μm.The alloy powder is placed in a vacuum drying oven,heated to 1200 C,and retained for 2 h.Then,it is cooled to room temperature in a vacuum environment,poured into a powder feeder,and placed in a feeding barrel for standby.Further,a 316 L stainless steel plate with dimensions of 100 mm×60 mm×10 mm is selected as the base plate,and the oxide layer on the surface is removed using a grinder.Additionally,an electric spark cutting machine is used to cut the AlCoCrFeNi_(2.5) HEA samples into different sizes based on the test requirements.A heat setting machine is used to inlay the samples that required grinding and polishing.The samples are polished with 240#,400#,800#,1200#,2500#,4000#metallographic sandpaper and SiC polishing solution with particle size of 0.05μm and 0.02μm,respectively The appropriate amount of aqua regia is prepared to corrode the polished samples.The X-ray diffractometer(XRD)is used to perform pha

关 键 词：材料 激光熔化沉积 高熵合金 微观组织 拉伸性能 

分 类 号：TG135.1[一般工业技术—材料科学与工程]