Contents I. Introduction
The aluminum foam was a kind of cellular structure metal which was widely used in the field of aerospace, aviation and transportation [1]. Mainly there were two processing methods indentified by the material states when adding blowing agents: the PM method [2] in solid state and the “Alporas” method [3] in liquid state. Both of the methods had been extensively studied by researchers all over the world [4], [5]. The thickening behavior of adding 1~5 wt% Al2O3 and SiC particles to the semi-solid melt was studied by M. Haesche and J. Banhart [3], [6] who stated that these particles would increase the stability of gas bubble if they were evenly distributed in the melts and would reduce the merging and cracking tendency of the bubbles; Some ADC12 Aluminum foam was obtained above the liquidus temperature without adding other thickening particles by complex stirring which was a combination of mechanical and electromagnetic stirring by C.G. Kang [7], [8]. Integrating the features of these two methods, the author created a novel method to fabricate the aluminum foam precursor using semi-solid stirring technique. Precursors embedded with blowing agents could been directly obtained by special stirring method together with cooling technique which used the character of high viscosity of semi-solid melt itself. The obtained precursors could be easily cut and foaming under certain temperature to get aluminum foam piece with nice quality. This method had shorter process and higher efficiency which also cost less than other methods. This paper mainly discussed the main principle of this new method as well as the effects of the main parameters in the fabricating process.
