Production of particles reinforced Al based sandwich metallic foams by powder metallurgy techniques and investigation of their mechanicial properties

This thesis comprises of the production of particles reinforced Al based sandwich metallic foams by using powder metallurgy techniques and investigation of their mechanical properties. In order to produce sandwich foam, aluminum, silicon, magnesium, titanium hydride (TiH2) powders and some ceramic particles (SiC, Al2O3, B4C) were mixed homogeneously and compacted under a constant pressure and some powder blanks were produced. Blanks were extruded at 500oC and then hot rolled in between Al plates at 500 ? C. Preform samples were foamed at 650, 670, 690, 710 ? C for various foaming duration (6-16 minutes) and then cooled to room temperature in air. It was determined that, increasing the foaming temperature and foaming duration resulted in an increase in pore size, the volume fraction of porosity and linear expansion rate. Increasing pore size and linear expansion rate resulted in a decrease in foam density of aluminum. High foaming temperature caused the reduction of the foaming duration. Addition of ceramic particles to the matrix increased the compressive strength of the foams whereas it was found to be detrimental to the three-point bending strength. High foaming temperature reduced the three-point bending strength and compressive strength of aluminum sandwich foams.