氩气雾化法制备FGH96高温合金粉末颗粒的凝固组织

利用扫描电镜(SEM)对氩气雾化(argon gas atomization,缩写AA)工艺制备的FGH96高温合金原始粉末颗粒的粘结形式、凝固组织、表面和内部形貌及其形成机理进行研究.结果表明:AA法制备的FGH96合金粉末,在颗粒尺寸d≥40 μm时,颗粒之间出现凸起式粘结、包覆式粘结以及葫芦式粘结,其中凸起式粘结...

Solidification microstructure of FGH96 superalloy powder prepared by argon gas atomization

Adhering formation,microstructure,morphology of particle surface and interior,as well as their formation mechanism of FGH96 superalloy powder particles,prepared by argon gas atomization(AA),have been investigated by scanning electron microscopy(SEM).The results indicate that,when the particle size d≥40 μm,FGH96 original powder particles appear convex-type bond,package-type bond,gourd-type bond,as well as convex-type bond are the main adhering formation.Both surface and interior of original powder particles show that when the particle size d≤30 μm,the solidification microstructures are cellular and microcrystal in major,and when the particle size d≥30 μm and gradually increases,the microstructures change from cellular in major to dendrite,and the number of radiation-type dendrite formed by the way of "multi-nucleation"increases.The relation between secondary arm space λ and particle size d can be expressed by λ=0.766+1.61×10-2 d.Solidification cooling rate of FGH96 superalloy powder,ranging from 103 to 105 K/s,is higher than the cooling rate of traditional microstructures,but lower than that of novel microstructures.This results in forming more refined microstructures of dendrite and cellular,and it also forms microstructures of microcrystal sized between 1 and 2 μm.But there are no novel microstructures appearing.