Enhanced Compressive Property of Al Composite Foams at Elevated Temperatures via Plasma Electrolytic Oxidation

The present work investigates the compressive property of Al matrix composite foams at different temperatures between room temperature and 200 degrees C. Elevated temperature results in a decreased compressive strength and energy absorption capacity of as-received Al foams. Therefore, to maintain the compressive property, the Al2O3 ceramic coating was deposited on the Al struts of the foams by the plasma electrolytic oxidation (PEO) process to form Al2O3/Al composite foams. As a consequence, the composite foams exhibit a higher compressive strength and energy absorption capacity as compared with the as-received Al foams at both room temperature and elevated temperatures because of the reinforced effect of the Al2O3 ceramic on the foam strut. The related mechanisms were explained by fractography, microstructure observation and phase composition analysis using scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDS) and X-ray diffraction (XRD).