Magnesium alloys have received much attention because of their high specific strength as well as recent advances in manufacturing processes. They have been applied in light-weight consumer electronics such as laptops and smartphone, and are being considered for automobile and aerospace applications. However, magnesium alloys can also have very anisotropic and evolving mechanical properties associated with processing-induced and evolving texture as well as the evolution of deformation twinning. The evolution of these microstructural variables with strain rate and pressure can strongly influence the behavior of these alloys under impact conditions. Here, we examine the response of a commercial magnesium alloy to impact over a range of velocities, including hypervelocities, using the HyFIRE facility at Johns Hopkins. The impact configuration consists of hard spheres impacting AZ31B magnesium alloy plates at various angles of incidence and over a range of impact velocities. The intent is to understand how the multiple mechanisms triggered by high-velocity impact (including high-rate deformations, spallation, fracture, and possibly melting) interact to result in global failure of the target. These impact experiments induce a range of strain rates and pressures, as well as multiaxial stress states, and result in complex damage states that are also affected by geometry and boundary conditions. We focus on understanding the anisotropic fragmentating debris expansion and damage evolution under these impact conditions using a range of in situ diagnostics (such as mutiple high-speed imaging) and post-mortem characterization (such as microscopy and micro-computed tomography). Both the design and interpretation of the experiments are aided by simulations.
2025-04-09 09:00:00
