粉床型电子束增材制造W-3.5Nb合金孔洞缺陷及其形成机制  

Formation Process of Pore Defect in W-3.5Nb Alloy Fabricated By Selective Electron Beam Melting

作　　者：杨广宇[1] 汤慧萍[1] 王建[1] 贾文鹏[1] 贾亮[1] 刘楠[1] Yang Guangyu;Tang Huiping;Wang Jian;Jia Wenpeng;Jia Liang;Liu Nan(State Key Laboratory of Porous Metal Materials,Northwest Institute for Nonferrous Metal Research,Xi’an 710016,China)

机构地区：[1]西北有色金属研究院金属多孔材料国家重点实验室,陕西西安710016

出　　处：《稀有金属材料与工程》2022年第2期573-578,共6页Rare Metal Materials and Engineering

基　　金：科学挑战专题项目(TZ2018006);陕西省重点研发计划(2021KW-34)。

摘　　要：采用粉床型电子束增材制造(SEBM)技术制备了W-3.5Nb合金,研究了电子束线能量密度对W-3.5Nb合金孔洞缺陷形成的影响规律,分析了不同类型孔洞缺陷的形成原因。结果表明:随着电子束线能量密度的升高,缺陷含量降低,当线能量密度升高到1.44 J/mm时,缺陷的体积含量最低为0.01%,继续增大线能量密度,缺陷的体积含量和数量有所增加。合金中孔洞缺陷可分为层间熔合不良、微米级树枝状孔、微米级近球形孔、纳米级球形孔4类。在线能量密度较低(1.08 J/mm)时,大尺寸(大于5000μm^(3))缺陷占主导,主要为层间熔合不良,形成原因主要是能量输入不足导致的熔池球化和熔化深度不足;当线能量密度升高后到1.32, 1.44和2.2 J/mm,小尺寸(小于2000μm^(3))缺陷占主导,其中的低球形度缺陷主要为微米级的树枝状孔洞,形成原因主要是熔池扰动引起的液体飞溅,高球形度的缺陷主要为微米级的近球形孔和纳米级球形孔,形成原因主要是熔池凝固过程中的凝固收缩和枝晶间的显微缩松。W-3.5Nb alloy was prepared by selective electron beam melting technology(SEBM). The influence of linear energy density on the formation of pore defects was studied. Different types of pore defects were analyzed. The results show that with the increase of the linear energy density, the defect content decreases, and the volume of defects is the lowest(0.01%) at the linear energy density of 1.44 J/mm. When the linear energy density continues to increase, the volume and quantity of defects increase. There are four types of pore defects in SEBM W-3.5Nb alloy: lack of fusion defects, micron dendritic pores, micron spherical pores and nano spherical pores. A t the low linear energy density, the large defect(>5000 μm^(3)) which is the lack of fusion caused by insufficient energy input and insufficient melting depth is dominant;when the energy density increases, the defect size is smaller(< 2000 μm^(3)), among which the low sphericity defects are the dendrites defect caused by the dynamic flow of molten pool, and the high sphericity defects are micro and nano spherical pores caused by the shrinkage of the melting pool and micro shrinkage between dendrit es during solidification.

关 键 词：增材制造(3D打印) 粉床型电子束增材制造 钨合金 缺陷 

分 类 号：TG146.411[一般工业技术—材料科学与工程]