Closed-cell Aluminum foam is a particular type of lightweight metallic material that can sustain considerable deformation under nearly constant stress which is known as plateau stress. Thus, under dynamic loading, aluminum foams can be used for energy absorption. However, these foams have a low plateau stress and are generally unsuitable for carrying structural loads. To improve foam mechanical properties graphene reinforcement has been used to enhance its dynamic mechanical response for applications at room temperature and high temperatures. Preliminary investigation was conducted at room temperature on graphene reinforced aluminum foam by Sinha et al. [1].
For this investigation, aluminum foams reinforced with graphene concentration varying between 0.2 – 0.62 wt.%, manufactured using the liquid metallurgy route were studied. The compressive dynamic behavior of this foam has been studied over a range of high strain rates up to 2200 s-1 using the Split Hopkinson Pressure Bar (SHPB) apparatus [2]. The mechanical response was studied at high temperatures of 473K, 623K, and compared to room temperature of 298K. Amongst the four different graphene compositions (0.20wt.%, 0.40wt.%, 0.50wt.% and 0.62 wt.%) studied, 0.62 wt.% displayed the maximum value of peak stress, plateau stress, and energy absorption. The experimental data obtained in the present study is supported using an empirical model.
It is observed that at high temperature, the values of peak and plateau stress decreased when compared with the values obtained at room temperature for reinforced foam. However, the high strain rate response of the reinforced foam at high temperature was equal or better than the response of unreinforced foam under similar loading conditions at room temperature.