Many of the impact events that occur in reality (e.g. car crash, a missile hitting an armor) are dynamic in nature, with the velocities ranging from few m/s to km/s. As these events are dynamic in nature, materials choose a different energy pathways to dissipate the plastic work. The deformation mechanisms that are operative under quasi-static conditions are no longer valid under dynamic loading conditions. For example in the case of some metallic materials it is widely established that the deformation at high strain rates results in heterogeneous deformation i.e., the deformation localizes into few narrow regions of the sample while in the case of ceramics the dynamic deformation activates multiple crack nucleation sites. Materials which are strain rate sensitive exhibit a higher strength during dynamic deformation.
Recently there has been increasing demand to develop lightweight structural materials for transportation industries (e.g. Automobile and aerospace) as they can reduce the weight of the vehicle there by resulting in considerable fuel savings and reduced green house emissions. Magnesium and its alloys are suitable for such applications because of their low density and high specific strength. However, the deformation mechanisms in these materials is not well understood owing to their low symmetry hexagonal close packed crystal structure. Many of the existing plasticity models fail to capture the deformation mechanisms especially at high loading rates. To develop Mg alloys with improved dynamic mechanical properties it is important to understand the deformation mechanisms, particularly at high loading rates. Our aim is to conduct high strain rate experiments on single, poly-crystalline Mg and its alloys to understand the deformation mechanisms and develop physics based equations which can be used in the crystal plasticity models.
During ballistic impacts armor ceramics are subjected extremely high loading rates and materials used for such applications should have high resistance for impact loads. In order to design new armor ceramics with improved ballistic performance, a combinatorial approach that involves detailed experimental and theoretical investigations is desirable. Our goal of this work is to identify the important microstructural actors that influence the dynamic deformation and find appropriate ways to control these actors so as to enhance the dynamics properties vis a vis the ballistic performance.