Development of aluminum metal foam with improved mechanical properties through the novel FSP technique

Aluminum 6063 metal foam with densities ranging from 0.885 to 1.5 g/cm3 was successfully formed using friction stir processing (FSP) method. To gain a fair control over the pore morphology, the relationship between FSP parameters and the resulting foam structure, as well as the mechanical properties, needs to be analysed. The effect of tool design parameters and the powder ratio of blowing and stabilizing agents on density and morphology was reported. A fractional factorial technique was used to optimize these factors, in order to interprettheir impact on the final foam structure. The approach led to high-quality metal foams with porosities ranging from 38.6% to 67.2%. The specific compressive strength and energy absorption capacity of 26.04 kNm/kg and 12 MJ/m3 respectively was observed for the foam with minimum relative density of 0.37. This study outlines that critical input parameters for producing the most efficient foam with the lowest density include ratio of blowing and stabilizing agents, traverse speed and spindle speed. Hence, it provides valuable insights for researchers working on the design and development of advanced foaming techniques aimed at controlling the essential physical properties of this important class of materials.