Effect of temperature and strain rate on the compressive deformation response of closed-cell aluminium hybrid foams

The hot deformation behaviour of Al-Si12CulMg1 alloy foam, Al-Si12CulMg1 alloy-single-wall carbon nanotubes (SWNTs), Al-Sil2CulMg1-cenospheres, and Al-Si12CulMg1-cenosphere-SWNTs hybrid foams (HFs) were investigated at different test temperatures (25-400 degrees C) and strain rates (10(-3)-1 s(-1)) conditions. It is observed that the energy absorption capacity of all the foams decreased with an increased test temperature (TT) whereas it increased with an increase in strain rate. The hybrid foam in which the cenosphere and SWNTs were added together exhibited the highest plateau stress and energy absorption amongst all investigated foams. The strain rate sensitivity and activation energy for each kind of foam was calculated as a function of temperature and strain rate. The activation energy data tells that the deformation mechanism is dominated by vacancy and dislocation diffusion at TT <= 200 degrees C regardless of the type of foam, strain rate and relative density. On the other hand, the deformation mechanism is dominated by dynamic recovery and recrystallization when the TT increase beyond 200 degrees C (TT > 200 degrees C). This study further demonstrates the synergistic effect of cenosphere and SWNTs on enhancing the plateau stress and energy absorption of HFs. (C) 2021 Elsevier B.V. All rights reserved.