Production, stability, and properties of in-situ Al–5ZrB2 composite foams

Stabilization is an essential requirement to produce closed-cell metal foams. In the melt route of foaming, usually ceramic particles are used as foam stabilizers. For the first time, the present study introduces ZrB2 particles as foam stabilizers. We demonstrate the foaming of in-situ based Al composite containing submicron ZrB2 particles. The effect of foaming temperature and holding time on the structural and mechanical properties of the foams was studied. The composites and foams were characterized using XRD, SEM/EDS, and optical scanning techniques. The mechanical properties of the foams were determined by subjecting the foams to a quasi-static compression test. Submicron ZrB2 particles present in the cell wall and at the gas-solid interface promoted foam stability. All the foams exhibited a good cellular structure with high expansion. Among all the foams, the foams prepared at 680 °C with a holding time of 120 s exhibited the smallest cell size and the best mechanical properties. The structural and mechanical properties of the Al–5ZrB2 foams were found to be comparable to conventional foams.