Energy absorption of thin-walled profiles made of AZ31 magnesium alloy

Abstract

The paper compares the energy absorption of the AZ31 magnesium alloy with the DC04 and HC380LA steel on the example of the thin-walled model profiles made by the process of bending. Additionally, the studies involved the application of aluminium foam filling the sections in order to increase their energy absorption.The first stage of the research included the elaboration of a technology of producing the thin-walled model profiles from a magnesium alloy by way of bending, with the use of tools heated to 270°C and 300°C. Next, the prepared sections halves were joined with the use of the FSW method. The static tensile tests showed that the FSW joints underwent damage in the native material or at the boundary with the heat-affected zone, which confirmed their high strength.The main aim of the use of the magnesium alloy was to lower the mass of the bodywork. And so, in order to compare the energy absorption of the profiles made of steel with those made of magnesium alloys, the mass of the samples should be taken into consideration. To that end, in the study, the parameter of specific energy absorption was introduced, which is the absorbed energy divided by the mass of the sample. The dynamic deformation tests performed on the profiles made of the AZ31 magnesium alloy and the DC04 and HC380LA steel demonstrated that the profiles made of only the AZ31 magnesium, due to their low deformability, do not exhibit sufficient energy absorption. In order to increase it, hybrid samples should be applied. The study proposed filling the profiles made of the AZ31 alloy with aluminium foam. This caused their specific energy absorption to be higher than that of the steel profiles.