Production of the Al3Ti foam by microwave heating

Al-Ti foams were produced by the combustion synthesis of blended powder compacts consisting of titanium and aluminum using microwave heating. Aiming at promoting the foaming behavior, the exothermic powder (titanium and B4C powders) was added to the blended powder to increase the combustion temperature. We examined the possibility of a microwave heating as the igniting method of a precursor. The effects of the exothermic powder addition and powder compacting pressure on the combustion foaming process were investigated. The microwave heating experiments were conducted by using a 500W, 2.45 GHz single-mode cavity. The precursors were heated in a maximum of magnetic field in the cavity. When the amount of the exothermic powder was 0 and 5vol%, combustion synthesis was identified, although the expansion of the precursor was not achieved. When the amount of the exothermic powder was 10vol%, the compacting pressure (25MPa ~ 200MPa) did not affect the porosity.