Fabrication of aluminum based composite foam by PM route using the blowing agent CaCO3

One of the major means to manufacture aluminum foams is forming a dense precursor material with powder metallurgical methods, wherein desired powders mixed with a blowing agent are consolidated by various routes i.e. axial compression, isostatic pressing, hot extrusion, rolling, etc. Then, resultant precursors will be subjected to foaming treatment. In this research, calcium carbonate, the foaming agents mostly used in meltbased methods, is used to fabricate Al-Si-SiC foam by PM route. Powder mixtures containing aluminum, silicon and silicon carbide and calcium carbonate powders, were subjected to cold uni-axial pressing and then hot extrusion at 450˚ C. Consequent precursors had cylindrical shape and their relative densities were from %90 to %98 of theoretical density. The precursors were foamed in a stainless steel cylindrical mold, at 850˚C for various time intervals. Density of foams produced varies in a narrow range of 0.508 upto 0.6 gr/cm3. The cellular structure also showed relatively uniform distribution of cells, with average diameter of approximately 154 μm. A foam sample was tested under uniaxial compressive load and compressive strength was 11.81 MPa accompanied by 4.803 MJ/m3 energy absorption.

Fabrication of aluminum based composite foam by PM route using the blowing agent CaCO3 Keywords:

Aluminum foams , powder metallurgy , blowing agent , Calcium carbonate