Microstructures variation of spray formed Si-30%Al alloy during densification process
(1.北京市北京有色金属研究总院有色金属材料制备加工国家重点实验室
2.State Key Laboratory for Fabrication and ProBeijing General Research Institute for Non-ferrous Metals, Beijing 100088, Chinacessing of Non-ferrous Metals,
3.State Key Laboratory for Fabrication and Processing of Non-ferrous Metals,Beijing General Research Institute for Non-ferrous Metals, Beijing 100088, China)
2.State Key Laboratory for Fabrication and ProBeijing General Research Institute for Non-ferrous Metals, Beijing 100088, Chinacessing of Non-ferrous Metals,
3.State Key Laboratory for Fabrication and Processing of Non-ferrous Metals,Beijing General Research Institute for Non-ferrous Metals, Beijing 100088, China)
Abstract: Microstructure variation of spray-formed Si-30%Al alloy during densification process by hot pressing was studied. The results indicate that the microstructure of as-deposited preforms is fine and homogenous. The primary silicon phases distributing in aluminium matrix evenly are fine and irregular. Aluminium matrix is divided into two groups: supersaturated α-Al phase or α-Al phase and Al-Si pseudo-eutectic phase or Al-Si eutectic phase. During hot pressing, the primary silicon and the aluminium matrix realign as follows: the primary silicon fractures at a given compressive stress, the particles congregates in microzone with increasing stress, and the aluminium matrix flows and connects in harness. Al-Si pseudo-eutectic phase turns into Al-Si eutectic phase due to the diffusion of atoms during densification process.
Key words: Si-30％Al alloy; spray forming; electronic packaging materials; microstructures variation; densification process