(华南理工大学 机电工程系, 广州 510640)
摘 要: 通过分析快速凝固高硅铝合金粉末在热挤压过程中的密度、微观组织和相结构的变化,对粉末热挤压成形机理进行了探讨。结果表明,快速凝固高硅铝合金粉末热挤压过程分为2个阶段,即填充挤压阶段和稳态流动阶段,粉末生坯的致密化主要在第一阶段完成。粉末颗粒中初晶Si相受到加热长大和挤压破碎两方面的综合作用,最终得到的挤压材料中的Si颗粒与原始粉末相比没有明显的粗化。合金的相组成在挤压前后没有发生变化,快速凝固合金的组织结构特征基本得以保留。
关键字: 快速凝固; 高硅铝合金; 热挤压
aluminumsilicon alloy powder
(Department of Mechanotronic Engineering, South China University of Technology,
Guangzhou 510640, P.R.China)
Abstract:By analyzing the changes of the density, microstructures and phase during the hot extrusion process of rapidly solidified (RS) hypereutectic aluminumsilicon powder, the mechanism of powder hot extrusion was studied. Experimental results show that the powder hot extrusion process can be divided into two stages, hot compress process and stable flow process. The density of the billet increases greatly at the first process. Two effects decide the primary silicon particle size: growing due to heating and breaking due to extrusion. However, no change of phase is detected after hot extrusion, and the powder's RS characteristics remain unchanged.
Key words: rapid solidification; hypereutectic Al-Si alloy; hot extrusion