中文摘要：

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≥40μm时,颗粒之间出现凸起式粘结、包覆式粘结以及葫芦式粘结,其中凸起式粘结是主要的粘结形式。原始粉末颗粒的表面与内部形貌显示,在颗粒尺寸d≤30μm时主要是微晶和胞状晶;当颗粒尺寸d≥30μm时,随着颗粒尺寸增大,组织逐渐由胞状晶向树枝晶转变,并且＂多点形核＂产生的放射状树枝晶的数量增多。树枝晶的二次枝晶臂距λ与颗粒尺寸d之间呈线性关系：λ=0.766＋1.61×10-2 d。粉末凝固冷却速率在103~105 K/s范围,高于传统显微组织的冷却速率,低于产生特殊显微组织的冷却速率;因此出现传统的树枝晶、胞状晶组织,但更加细小,未出现特殊的显微组织,却产生了1~2μm的微晶组织。

英文摘要：

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.