电子束选区熔化W‒B合金的显微组织和力学性能  

Microstructure and mechanical properties of W‒B alloys prepared by selective electron beam melting

作　　者：游亮 王建[2] 杨广宇[2] YOU Liang;WANG Jian;YANG Guangyu(School of Materials Science and Engineering,Northeastern University,Shenyang 110819,China;State Key Laboratory of Porous Metal Materials,Northwest Institute for Nonferrous Metal Research,Xi’an 710016,China)

机构地区：[1]东北大学材料科学与工程学院,沈阳110819 [2]西北有色金属研究院金属多孔材料国家重点实验室,西安710016

出　　处：《粉末冶金技术》2024年第6期600-608,651,共10页Powder Metallurgy Technology

摘　　要：针对电子束选区熔化纯钨晶粒粗大的问题,选取B作为晶粒细化元素,研究成形工艺参数对W‒B合金致密化、显微组织和力学性能的影响。结果发现,当电子束束流强度为15 mA,扫描速度为300 mm·s^(‒1),体能量密度为1200 J·mm^(‒3)时,W‒B合金试样相对密度最高,孔洞及未熔合缺陷最少,微裂纹基本得到抑制。B元素引起的成分过冷有效细化了W晶粒尺寸,显微组织由粗大柱状晶转变为细小的柱状树枝晶,平均晶粒尺寸为8.26μm。W‒B合金的最高硬度达到HV 672,最高抗压强度达到1598 MPa,断裂机制为解理断裂。To solve the problem of grain coarseness in pure tungsten prepared by selective electron beam melting(SEBM),B was selected as the grain refinement element.The influence of forming process parameters on the densification,microstructure,and mechanical properties of the W‒B alloys was investigated.It is found that when the electron beam current intensity is 15 mA,the scanning speed is 300 mm·s^(‒1),and the volume energy density is 1200 J·mm^(‒3),the density of W‒B alloy samples is the highest,the pores and unfused powders are the least,and the microcracks are basically suppressed.The constitutional undercooling caused by element B effectively refines the grain size of W formed by SEBM,and the microstructure changes from coarse columnar crystal to fine columnar dendrites with an average size of~8.26μm.The highest hardness of the W‒B alloys is HV 672,and the highest ultimate compressive strength is 1598 MPa.The fracture mechanism is mainly cleavage fracture.

关 键 词：电子束选区熔化 W−B合金 成分过冷 晶粒细化 

分 类 号：TF125[冶金工程—粉末冶金] TG146.4[冶金工程—冶金物理化学]