Effect of elemental powder blending ratio on combustion foaming behavior of porous Al–Ti intermetallics and Al3Ti/Al composites

Porous Al–Ti intermetallics and Al3Ti/Al composites were fabricated by combustion foaming process. Fundamentally, aluminum and titanium powders were blended (Al/Ti mole blending ratios ranging from 0.33 to 10.0). Additionally, boron carbide (B4C) powder was blended as exothermic agent since the heat of TiC and TiB2 formation is much higher than those of Al–Ti intermetallics. The blended powder compact was heated to induce the combustion reaction. Isotropic closed pores were produced by this process. By adding 10 vol.% exothermic agent, the porosity exceeded 60% in a wide range of Al/Ti ratios (3.0–10.0). It was confirmed that high heat of reaction of exothermic agent assisted the complete conversion of aluminum and titanium powders to Al3Ti.