Compressive behavior of Mg alloy foams at elevated temperature

Abstract

It is the purpose of this work to investigate compressive behavior of closed-cell Mg alloy foams fabricated by melting method at elevated temperature. First, the Mg alloy foams were characterized by scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDS) and X-ray diffraction (XRD) for microstructure, composition and phases, respectively. Then, the compressive tests were carried out on closed-cell Mg alloy foams at room temperature (25 °C), 200 °C, 400 °C and 500 °C. It is found that the effect of temperature on compressive behavior of the Mg alloy foams is different between high temperature and low temperature. The Mg alloy foams exhibit a brittle compressive behavior at room temperature by the fracture of cell walls. However, the pure brittle fracture mode transforms into a combination of brittle fracture mode and ductile fracture mode at temperature in the range of 200 °C–400 °C. This indicates a soften effect of high temperature on the foams matrix and the plasticity of the cell walls at low temperature. It is concluded that the compressive strength and energy absorption capacity of the closed-cell Mg alloy foams decrease with the increasing temperature. Furthermore, a new method of defining the densification strain is proposed based on the perspective of energy absorption efficiency.