Compressive properties of the magnesium matrix syntactic foams using different types of porous volcanic rock particles

Abstract

The novel magnesium matrix syntactic foams were successfully fabricated by using two types of porous natural volcanic rock (VR) particles as reinforcements. The effects of particle properties and testing temperature on the mechanical properties and energy absorption characteristics of the syntactic foams were systematically investigated. The obtained syntactic foams have good quality, high specific compressive properties at different temperatures. Two types of VR particles have different densities, morphologies, compositions and crushing strengths, inducing obvious contrasts in apparent density, mechanical properties and energy absorption characteristic of two kinds of syntactic foams. The syntactic foams containing high-density VR (HD-VR/Mg) have superior compressive strength, plateau strength and energy absorption capacity, while the syntactic foams containing low-density VR (LD-VR/Mg) exhibit lower density (0.89 g/cm3), higher porosity (49.5%) and more stable deformation behavior. At room temperature (RT), the failure of HD-VR/Mg syntactic foams is mainly controlled by shear fracture mode; in contrast, the failure of LD-VR/Mg syntactic foams is mixed modes. In addition, the compressive properties and energy absorption capacity of syntactic foams are depending on testing temperature. The compressive strength, plateau strength and energy absorption capacity of both syntactic foams gradually decrease with increasing temperature. The corresponding dominant failure mechanism of VR/Mg syntactic foams shifts due to the increased plasticity of Mg struts with increasing temperature.