电极感应熔化氩气雾化中液滴尺寸影响因数及粉末特性的研究

Study on Powder Characteristics and Droplet Size Influence Factor in Electrode Induction Melting Argon Atomization

摘要:

本文对电极感应熔化气雾化(Electrode induction melting gas atomization,缩写EIGA)工艺制备的镍基高温合金粉末的物理特性,凝固组织以及内部元素分布进行研究分析；理论分析了EIGA制粉一次雾化过程中液滴尺寸的影响因数；根据对流换热原理计算了该工艺中不同尺寸粉末的冷却速率。结果表明：EIGA粉末以近球形为主,霍尔流速为(13.4s/50g),D90=121.5μm。粉末表面和内部凝固组织显示,随着粉末尺寸的增大组织均由微晶向胞状晶和树枝晶转变。同时颗粒表面组织之间的间隙不断加深,粉末光滑度下降。在雾化气压为4MPa条件下时,粉末尺寸与冷却速率的关系为：。粉末内部没有明显的成分偏析现象,但晶轴和晶间的元素分布略有差别。晶轴上Ni、Al、Co、C元素含量较晶间高,晶间的Ti、Mo、Cr、Nb元素含量更高。

Abstract:

Abstract: In this paper, we investigated the physical characteristics, solidification microstructure, and inter element distribution of Ni-based superalloy powders, which prepared by electrode induction melting gas atomization (EIGA) process. Some factors on metal droplet size during primary atomization were also deeply analyzed. The cooling rate of different size powders were calculated through convective heat transfer principle. It is found that the EIGA powders are mainly spherical, the Hall flow rate is 13.4s/50g, and the D90 is 121.5μm. The microstructure of powders on surface and internal changes from microcrystals to cell crystals and dendrites increasing with the powder size. At the same time, the smoothness of powders decreases as the gap increases on the surface. The relationship between cooling rate and particle size is |〖dT〗_d/dt|=〖8.98*10〗^(-5)/d^2 , when the atomization gas pressure is 4MPa. There is slightly segregation in crystal axis and intercrystal of powders. The content of Ni, Al, Co, and C in crystal is higher than intergranular, while the content of Ti, Mo, Cr, and Nb in intergranular is much higher.