Abstract
Al2O3 hollow particles were used to manufacture 7055 Al-matrix syntactic foams using a simple gravity infiltration casting method. The effects of infiltration temperature and heat treatment process on microstructures, compressive properties, and energy absorption properties of the prepared Al-matrix syntactic foams were studied. The average density and porosity of the Al-matrix syntactic foams are 1.73 g cm^–3 and 40.89 %, respectively. The maximum compressive yield strength and compressive strength of the as-cast Al-matrix syntactic foams are 78.23 MPa and 79.52 MPa, respectively. After solution-aging treatment, the compressive strength and yield strength of the Al-matrix syntactic foams are significantly improved. After normalizing, the average compressive plateau stress and energy absorption performance are the best. The highest energy absorption capacity and specific energy absorption are 48.14 MJ m^–3 and 28.04 kJ kg^–1, respectively. This result reached or exceeded the energy absorption properties of many Al-matrix syntactic foams prepared by other processes reported in recent years.

Key words
aluminum matrix syntactic foams (AMSFs), gravity infiltration casting, heat treatments, compressive property, energy absorption performance

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