(哈尔滨工业大学金属精密热加工国防科技重点实验室，哈尔滨 150001)
摘 要: 研究了高温合金喷射成形过喷粉末凝固组织特征。结果表明：粉末呈相当圆整的球形，内部组织随颗粒粒度的不同呈现多晶核与单晶核生长及发达与欠发达枝晶形态，粉末粒度在10～200μm之间，冷却速度在103～106 K/s之间。并从热传输和凝固过程上简要分析了过喷粉末快速凝固组织的形成机制。
关键字: 高温合金 合金粉末 显微组织
（National Defense S and T Key Lab of Metal Precision Hot Processing,
Harbin Institute of Technology, Harbin 150001, P. R. China）
Abstract:The microstructure characteristics of over-sprayed Nickel-based superalloy powders were investigated. The results showed that the particle of powder exhibits regular spheroid morphology. The microstructures of particles display multi-sites and single-sites nucleation and well-developed, less-developed dendrites, depending on the size of powders. The size of particle is 10～200 μm, and the cooling rate of powders is 103～106K/s. Formation mechanisms of the powders with different size are explained in terms of the corresponding heat transferring and solidifying histories.
Key words: superalloy; alloy powder; microstructure
