EffectofP_Mvalueonthe_省略_ayformed70Si30A.pdf

Journal of University of Science and Technology Beijing Materials Volume 14, Number 2, April 2007, Page 141 Effect of P/M value on the preforms and microstructures of spray formed 70Si30Al alloy Yanguang Wei, Baiqing Xiong, Yongan Zhang, Hongwei Liu, Feng Wang, and Baohong Zhu State Key Laboratory for Fabrication Processing of Nonferrous Metals, Beijing General Research Institute for Nonferrous Metals, Beijing 100088, China (Received 2006-06-05) Abstract: A novel 70Si30Al alloy was prepared by the spray forming process for electronic packaging materials. The effect of the ratio of atomization pressure to metal melt mass flux rate (P/M) on the preforms and microstructures of the spray-deposited 70Si30Al alloy was studied. The results indicate that the P/M value has a considerable influence on the formation of the preforms and the optimal value is in the range of 0.209-0.231 MPa/(kg⋅min−1). The microstructure of the spray formed 70Si30Al alloy is fine and homogenous. The primary silicon phases distributing in the aluminum matrix evenly are fine and irregular. The aluminum matrix is divided into two groups: supersaturated α-Al phase or α-Al phase and Al-Si pseudoeutectic phase or Al-Si eutectic phase. Key words: 70Si30Al alloy; spray forming; atomization pressure; mass flux rate; microstructure [This study was financially supported by the National Basic Research Program of China (.] 1. Introduction 13]. There is a complex process involving heat transmis- A new family of spray formed Si-Al alloy (Al- sion, mass transfer, and solidification in spray forming (50wt%-70wt%)Si) developed for electronic packag-