Abstract:An innovative approach that utilizes a graphite coating treatment (GCT) on precursors of aluminum foam sandwich (AFS) panels was proposed to improve heat transfer efficiency during the powder metallurgical foaming process. The heating and expansion characteristics, effects on cell structures and bending performance of different heat transfer methods were studied. The results indicated that the heating rates of precursors increased by approximately two-fold after applying GCT, resulting in improvements in the expansion ratio, cell size uniformity, and panel surface morphology of the AFS. Furthermore, the later stage of foaming featured a more consistent heating rate, increasing cell roundness and reducing microporous defects within cell walls. These advancements consequently bolstered the bending strength and energy absorption properties of AFS. Notably, GCT technology holds great potential for the production of large-format AFS, as the heat transfer rate remains unaffected by panel size.

Key words: aluminum foam sandwich; powder metallurgy foaming; efficient heat transfer; graphite coating treatment; cell structure