雾化气体和冷却速率对镍基合金粉末凝固特性的影响（英文）  

Influence of Atomizing Gas and Cooling Rate on Solidification Characterization of Nickel-based Superalloy Powders

作　　者：方鹏均 徐轶[1,2] 黎兴刚 陈亚 

机构地区：[1]西南交通大学材料科学与工程学院,四川成都610031 [2]不来梅大学材料技术研究所,不来梅德国28359 [3]北京有色金属研究总院国家有色金属复合材料工程技术研究中心,北京100088 [4]西南交通大学体育科学研究所,四川成都610031

出　　处：《稀有金属材料与工程》2018年第2期423-430,共8页Rare Metal Materials and Engineering

基　　金：National Natural Science Foundation of China(51301143);the National Postdoctoral Foundation of China(2014M560727);the Sichuan Province Science-Technology Support Plan,China(2015GZ0228);the Science and Technology Innovation Project of SWJTU University,China(2682014CX001)

摘　　要：分别采用氩气和氮气作为雾化介质,制备得到镍基合金粉末。利用扫描电镜分析2种气体雾化的粉末表面形貌及凝固组织特征。基于牛顿冷却模型,对雾化粉末冷却速度和飞行速度进行数值计算。结果表明:冷却速率决定了凝固微观组织形貌。在较低的冷却速率下,2种气体雾化粉末均呈现发达的枝晶组织,而随着冷却速率的增大,氩气雾化粉末呈现欠发达的枝晶和胞晶混合组织。而氮气雾化粉末仅呈现胞晶组织。不同粒径氩气雾化粉末冷却速率在1.0×10~5~4.24×10~6 K·s^(-1),氮气雾化粉末在1.0×10~5~4.8×10~6 K·s^(-1)。冷却速率随粉末直径增加而减小。在快速凝固过程中,Cr,Co,W,Ni和Al等元素仍沿晶轴偏析,而Ti元素沿晶间偏析。Nickel-based superalloy powders have been produced by high pressure argon gas and nitrogen gas atomization, separately. The microstructural characterization of nickel-based alloy powders has been performed by a scanning electron microscope equipped with an EDS microanalysis unit. Based on a Newtonian cooling model, the flight speed and the cooling rate of two kinds of alloy droplets were calculated. The results show that the droplet cooling rate, which depends on atomization medium and droplet size, has an effect on the solidification microstructure. For argon-gas atomized powders, the developed dendrite structure is predominant at a lower cooling rate and a mixed microstructure composed of dendrite structure and cellular structure is observed at a higher cooling rate. For nitrogen-gas atomized powders, the dendrite structure is predominant at a lower cooling rate and a full cellular structure can be observed at a higher cooling rate. According to calculation, the cooling rate of argon-gas atomized droplets is in a range from 1.0×10^5 K·s^-1 to 4.24×10^6 K·s^-1, while the cooling rate of nitrogen-gas atomized droplets is from 1.0×10^5 K·s^-1 to 4.8×10^6 K·s^-1. The cooling rate increases with decreasing of droplets diameter. Two kinds of atomizing gases have a slight influence on the cooling rate of droplets. The dendrite axis is rich in elements such as Cr, Co, W, Ni and Al while the inter-dendrite region is rich in Ti element.

关 键 词：镍基合金粉末 气体雾化 凝固组织 冷却速率 

分 类 号：TF123.71[冶金工程—粉末冶金]