Study On The Preparation Of Aluminum Foams

Foamed metal is a new kind of structural and functional composite material. The idea of producing metal foams was first investigated over forty years ago, but it is only in the last decade that a number of processes have been proven successfully. Direct addition of gas to a melt is widespread because of its convenience and low-energy consumption as one of way of melt-based route.Because the foaming behaviours of aluminum melt caused by blowing gas into the melt are complex comprehensive porosity is employed to describe it in this paper .The influences of the initial foaming temperature, weight percentage of Al2O3 , flow rate of gas and foaming stirring time on the foaming behaviours were discussed and the optimal processing parameters were obtained. Moreover, based on the measurement of temperature in the sides of the mold, the curves were plotted, in order to study the effect of different cooling speed on the ability of "grasping" bubble of aluminum melt. On the basis of the above, the device of horizontal continuous casting of foamed aluminum was developed.The results showthat the optimal processing of massive aluminum which has excellent foaming effect with average porosity 62.9% is the initial foaming temperature 665C - 685C, 2% Al2O3 and stirring 10 minutes. The influence of foaming is considered to attribute greatly to the initial foaming temperature. During the process of solidification water-cooling is more beneficial to foaming and grasping gas than air cooling, so porosity would be enhanced.