Dynamic-compression mechanical properties and energy-absorption capability of fly-ash cenospheres-reinforced 1199Al-matrix composite foam

The fly-ash cenospheres-reinforced 1199Al-matrix composite foam was prepared by the pressure infiltration technique, in which containing the 80-μm-sized fly-ash cenospheres with the volume fraction of 0.4. Dynamic compression experiments were performed with a split Hopkinson pressure bar (SHPB) setup to investigate the dynamic compression properties and energy-absorption capability of the prepared composite foam in the strain rate range from 1700 s^-1 to 2900 s^-1. And the fractured surfaces of the compressed specimens were observed by a scanning electron microscopy. Moreover, the energy-absorption capability and the deformation mechanism of the prepared composite faom in dynamic compressions were compared with those of it in quasi-static compressions by an Instron 5569 tensile machine. The results show that the cenospheres-reinforced 1199Al-matrix composite foam is a strain-rate sensitive material. Its flow stress and plastic strain at the high strain rates are obviously higher than those under the quasi-static conditions. And the strain-rate hardening effect can more markedly influence the flow stress of the cenospheres-reinforced 1199Al-matrix composite foam than the strain-hardening effect. Furthermore, there are some differences between the quasi-static and dynamic compressive deformation mechanisms in the cenospheres-reinforced 1199Al-matrix composite foam. Under dynamic loadings, the fly-ash cenospheres in the cenospheres-reinforced 1199Al-matrix composite foam can be simultaneously compressed when the Al-matrix material is being filled, and there lies a good coordinate deformation capacity between the components.