Reinforcement effect of fly ash with different morphologies on aluminum foam prepared via powder metallurgy

Powder metallurgy has outstanding advantages in the preparation of aluminum foam fillers and special-shaped aluminum foams, which can realize near-net-shape forming. To improve the mechanical properties of aluminum foams prepared by powder metallurgy, low-cost solid waste fly ash (FA) was selected as the reinforcement phase, and the strengthening effect of the FA particles with different morphologies on the mechanical properties of the aluminum foam was analyzed. The results show that the strengthening effect of 1.0 wt% mullite whiskers prepared from the original FA on aluminum foam is superior to that of spherical raw FA or irregular granular FA. In particular, a reinforced aluminum foam with a yield strength of 20.76 MPa was obtained after precursor foaming at 610 °C for 10 min because the wettability between the whiskers and matrix is improved when the whiskers were coated with Sn in advance and the foamable precursor was obtained via hot-pressing. •The whiskers were pinned inside the cell walls to form the thicker cell walls.•Hot-pressing was very important to improve the strength of aluminum foam.•The strength of aluminum foam with improved wettability reached 20.76 MPa.