Processing and Stability of LM25/SiCP Composite Foams

作者：Kumar N V Ravi^*; Gokhale A A

来源：Transactions of the Indian Institute of Metals, 2012, 65(6): 753-757.

DOI：10.1007/s12666-012-0217-7

• Al-Si/SiCP composite
• Closed cell foam
• Liquid metal processing
• Foam collapse

A simple method of metal foam production is to introduce a blowing agent (e.g. TiH2) into an aluminium melt containing foam stabilisers such as oxides (usually Ca-based) and/or particles (e.g. SiC, Al2O3). In this work, Al/SiC composites (in-house and commercial Duralcan) [both of them with LM25 matrix (Al-7Si-0.3Mg)] containing particles of various sizes and contents were foamed at different temperatures using TiH2. Foamability is characterised through their expansion and collapse. It is observed that high expansions and good quality foams could be obtained upon manipulating SiC particle size and content. However, irrespective of particle size/vol.% combination, significant effect of foaming temperature is noticed on the fundamental stability of the liquid foam until solidification. Both cell size and foam density varied along the ingot height. The distribution of SiCP within the cell wall is random with no preferential segregation to gas/metal interface. The evolution of foam, and the role of SiC on foam stability are discussed based on macro and cell wall microstructural results.

• 出版日期2012-12