The effect of cooling rate on the structure and propert of closed-cell aluminium foams

摘要

The application of different cooling rates as a strategy to enhance the structure of aluminium foams is studied. The potential to influence the level of morphological defects and cell size non-uniformities is investigated. AlSi6Cu4 alloy was foamed through the powder compactroute and then solidified, applying three different cooling rates. Foam development was monitored in situ by means of X-ray radioscopywhile foaming inside a closed mould. The macro-structure of the foams was analysed in terms of cell size distribution as determined byX-ray tomography. Compression tests were conducted to assess the mechanical performance of the foams and measured properties werecorrelated with structural features of the foams. Moreover, possible changes in the ductile–brittle nature of deformation with cooling ratewere analysed by studying the initial stages of deformation. We observed improvements in the cell size distributions, reduction in micro-porosity and grain size at higher cooling rates, which in turn led to a notable enhancement in compressive strength.