Study on activation energy and strain rate sensitivity of closed -cell aluminium hybrid composite foam

High-temperature deformation behavior of LM13 aluminium alloy foam and LM13-silicon carbide (SiC)-multiwall carbon nanotube (MWCNTs) hybrid composite foams (HCFs) was studied and compared with that of LM13-SiC and LM13-MWCNTs composite foams at a temperature range of 25 °C–400 °C and strain rate ranging from 0.001 to 1 s−1. It is noted that the plateau stress and energy absorption decreased with the increasing temperature but increased with increasing the strain rate. Irrespective of kind of foams the combined effect of temperature and strain rate were investigated and the activation energy was determined for each type of foams as a function of temperature and strain rate. The cell walls collapse and microstructural changes during hot deformation were also examined. The hybrid composite foam exhibited the highest plateau stress, modulus, and energy absorption, whereas the alloy foams are softer foam with the lowest plateau stress, modulus, and energy absorption. At temperature <200 °C the deformation is vacancy and dislocation diffusion-controlled whereas at temperature >200 °C the deformation is controlled by dynamic recovery and recrystallization. © 2020 Elsevier B.V.