Experimental Measure of Parameters: The Johnson–Cook Material Model of Extruded Mg–Gd–Y Series Alloy

Abstract

This paper introduces a method to determine the material constants for Johnson–Cook model of an as-extruded Mg–Gd–Y series alloy by quasistatic tests on Instron 1251 and Hopkinson bar experiment at room and elevated temperatures. The results indicate that the thermal softening exponent of the current magnesium alloy is as high as 3.05, which is obviously higher than that of most metal materials, such as steel and tungsten. High thermal softening exponent usually means high energy absorption efficiency, and the comparison of the dynamic stress-strain curves between ZK60 and Mg–Gd–Y series alloy indeed indicates that the energy absorption efficiency of the Mg–Gd–Y series alloy is higher than that of ZK60. Additionally, high energy absorption efficiency makes the Mg–Gd–Y series alloy exhibit more excellent antipenetration performance than that of 7A52 aluminum alloy at equal areal density condition.