Evolution of Rheological Microstructures in Spray Deposition

Zhao Aimin Mao Weimin Zhen Zisheng Zhai Huaying Zhong Xueyou

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Evolution of Rheological Microstructures in Spray Deposition
Issue S1, Pages: 242-246(2001)
Published：2001
DOI：
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[1]赵爱民,毛卫民,甄子胜,翟华英,钟雪友,姜春梅,高元植,胡宜平.喷射沉积过程中半固态流变组织演变[J].特种铸造及有色合金,2001(S1):242-246. DOI：

Zhao Aimin Mao Weimin Zhen Zisheng Zhai Huaying Zhong Xueyou. Evolution of Rheological Microstructures in Spray Deposition[J]. Special Casting & Nonferrous Alloys, 2001, (S1): 242-246. DOI：

摘要

分析了喷射沉积过程中半固态流变组织演变过程

提出喷射沉积合金细小的等轴晶的凝固组织是飞行阶段快速冷却和沉积阶段沉积体表面糊状凝固层中半固态流变组织演变的结果

沉积体凝固过程是一种微米级流变铸造过程:不同大小、不同状态、不同温度、不同的运动速度的雾滴以高速高频的雾滴撞击沉积体表面

产生足够的剪切应力和剪切速率

使沉积体半固态糊状凝固层具有流变特性

飞行阶段形成快速凝固组织在沉积阶段沉积体表面糊状凝固层中发生变温粗化

最终形成细小的等轴晶。

Abstract

This paper analyses the evolution process of rheological microstructures in spray deposition. Presents that the fine equiaxe grain in spray casting alloys is the results of rapid cooling of the melt during droplet flight and evolution of rheological microstructures in mushy layer on the top of deposition billet. The microstructure evolution in deposition billet can be viewed as a micron scale rheocasting. A mass of droplet which have different size

different state

different temperature and speed impact the surface layer of billet and consolidate on it. The stress and strain velocity is high enough to break - up of fine dendrites in rapidly cooled droplets. The mushy layer on top of billet possess rheological characteristic. The fine dendrites in rapid solidification droplets during droplet flight coarsen in the mushy rheological layer. Finally the fine equiaxe grain formed