氢化脱氢法制备Nb-Si基超高温合金粉末的研究  

Study on Preparation of Nb-Si Based Ultra-high Temperature Alloy Powder by Hydrogenation-dehydrogenation Method

作　　者：魏振河 廖军华 沙江波[1] WEI Zhen-he;LIAO Jun-hua;SHA Jiang-bo(School of Materials Science and Engineering,Beihang University,Beijing 100191,China)

机构地区：[1]北京航空航天大学材料科学与工程学院,北京100191

出　　处：《精密成形工程》2022年第11期153-162,共10页Journal of Netshape Forming Engineering

基　　金：国家自然科学基金(51771006);国家科技重大专项(2019-VII-0016-0157)。

摘　　要：目的为了获得低成本、短流程制备的增材制造用Nb-Si基超高温合金粉末,采用氢化脱氢法制备了Nb-16Si-24Ti-2Hf-2Cr-0.3Sc(原子数分数)合金粉末。方法利用扫描电子显微镜(SEM)、能谱分析仪(EDS)、X射线衍射仪(XRD)、激光粒度分析仪及氧氮氢分析仪等对不同氢化脱氢工艺参数条件下所制备粉末的形貌、相组成、粒度、氢氧含量进行了表征。结果正交实验结果表明,氢化时间、氢化压力和氢化温度3个参数中,氢化温度对吸氢、吸氧量的影响最大;在粉末破碎效果差异不大的前提下,氢化温度200℃、氢化压力3 MPa、氢化时间1.5 h时,粉末中氧含量最小,氢化组织为Nb固溶体相Nb_(SS)、NbH_(x)相、Nb_(5)Si_(3)相及Nb_(2)O_(5)相。在600、700、800℃条件下分别对氢化粉末真空脱氢2 h后,粉末中均无残存的NbH_(x)相,其中,700℃/2 h的脱氢条件下Nb-Si基合金粉末氧含量最低。结论经过200℃/3 MPa/1.5 h氢化和700℃/2 h真空脱氢后制备的Nb-Si基合金粉末具有较低的氢氧含量,粉末形貌为等轴状,该粉末已用于激光熔覆增材技术,成功制备出Nb-Si基合金块体材料。The work aims to obtain ultra-high temperature alloy powders for additive manufacturing with low cost and short process preparation,Nb-16Si-24Ti-2Hf-2Cr-0.3Sc(at.%)powders were prepared by hydrogenation-dehydrogenation method.The morphology,phase composition,particle size and hydrogen/oxygen content of the powders prepared under different hydro-genation-dehydrogenation process parameters were characterized by using scanning electron microscopy(SEM),energy-dispersive spectrometer(EDS),X-ray diffractometer(XRD),laser particle size analyzer and O/N/H analyzer.Orthogonal test confirmed that among the three parameters of hydrogenation time,hydrogenation pressure and hydrogenation temperature,hydrogenation temperature had the greatest effect on hydrogen and oxygen uptake.Under the premise of little difference in powder crushing effect,when the hydrogenation temperature was 200℃,the hydrogenation pressure was 3 MPa,and the hydrogenation time was 1.5 h,the oxygen content in the powder was the minimum,and the hydrogenation structures were Nb solid solution phase Nb_(SS),NbH_(X),Nb_(5)Si_(3) and Nb_(2)O_(5).When the hydrogenated powder was dehydrogenated in vacuum at 600、700、800℃for 2 h,there was no residual NbH_(X) phase,and the Nb-Si based alloy powder had the lowest oxygen content under the dehydrogenation condition of 700℃/2 h.Under the hydrogenation parameters of 200℃/3 MPa/1.5 h and the dehydrogenation parameters of 700℃/2 h,the Nb-Si based alloy powders had relative low oxygen content,and the powder morphology was equiaxial.The equiaxed Nb-Si-based alloy powders have been successfully used to make ingot using laser melting deposition additive manufacture technology.

关 键 词：Nb-Si基合金 氢化脱氢法 氢氧含量 正交实验 

分 类 号：TF123[冶金工程—粉末冶金]