Transactions of Nonferrous Metals Society of China The Chinese Journal of Nonferrous Metals

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中国有色金属学报

ZHONGGUO YOUSEJINSHU XUEBAO

第14卷    第7期    总第64期    2004年7月

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文章编号:1004-0609(2004)07-1106-06
粉末冶金发泡时泡沫铝孔结构及泡壁的
微观组织演变
朱勇刚, 陈  锋, 梁晓军, 何德坪

( 东南大学 材料科学与工程系, 南京 210096)

摘 要: 研究了粉末冶金法制备泡沫铝时泡沫孔结构及胞壁微观组织变化的规律。泡沫铝发泡时经历微膨胀、 显著膨胀和收缩等过程; 孔结构经历了形核和长大, 以及在毛细力和重力驱动下泡壁熔体的流动引起的合并粗化和孔隙率自上而下梯度减小等演化过程。加热时, 铝/硅颗粒边界处硅的扩散层首先熔化,并沿着铝颗粒边界扩散, 最终使铝硅粉末复合体完全熔化而实现合金化。 实验发现泡壁的凝固组织与典型的变质处理后的铸造铝硅合金的组织类似。 

 

关键字: 泡沫铝; 粉末冶金; 孔结构; 微观组织

Evolution of pore morphology and cell wall microstructure of 
aluminum foam during powder metallurgical foaming
ZHU Yong-gang, CHEN Feng, 
LIANG Xiao-jun, HE De-ping

Department of Materials Science and Engineering, 
Southeast University, Nanjing 210096, China

Abstract: Evolution of pore morphology and cell wall microstructure of aluminum foam during powder metallurgical foaming was studied. It was found that aluminum foam shows three stages during foaming, that is tiny expansion, remarkable expansion and shrinkage; and the pore morphology goes through three stages, that is nucleation and growth, merging and coarsening, and the porosity decreasing from the upper part of the foam to the lower part of the foam. The merging and porosity gradient of the pore structures were resulted from capillarity-driven and gravity-driven melt flow within the melt foam column. The silicon diffusing layer along the boundary of aluminum and silicon powders melts firstly during the heating, and then the melt diffuses along the boundary of the aluminum powders, resulting in the entire alloying between aluminum and silicon powders. The experiment shows that the solidified cell wall microstructures are similar to those of typical modified cast Al-Si alloys. 

 

Key words: aluminum foam; powder metallurgy; pore morphology; microstructure

ISSN 1004-0609
CN 43-1238/TG
CODEN: ZYJXFK

ISSN 1003-6326
CN 43-1239/TG
CODEN: TNMCEW

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