Zach’s research aims to interrogate the multiaxial yield surface of magnesium alloys and investigate both the plastic flow behavior and the possibility of load-path dependence beyond the yield surface.
Magnesium alloys compose the lightest class of structural alloys and, as such, have drawn the attention of automotive, aerospace, and defense industries for the purpose of lightweighting. A recent application area of interest for magnesium alloys is lightweight tank armor. Anisotropic alloys like those of magnesium, however, exhibit properties that are dependent upon the direction in which load is applied. Additionally, combined loading often fails to follow the rule of superposition, and multiaxial load tests are required to more accurately investigate these combined loads. Magnesium alloys in particular are known to possess strong tendencies for deformation twinning, which adds to their anisotropy and has the potential to induce both path dependence and significant nonassociative plastic flow characteristics.
Zach utilizes the custom biaxial load frame to produce a variety of plane-stress states in high-energy diffraction microscopy experiments to gather multiaxial stress-state data at the grain scale. Digital image correlative techniques are also used to observe surface strains. Together, the stress and strain data provide insight into the multiscale behavior of magnesium alloys.
Research funded by Army Research Lab
Collaborators: Rich Becker and JeffLloyd, Army Research Lab; Jun-Sang Park and Jonathan Almer, Argonne National Laboratory; Garrison Hommer, Branden Kappes and Aaron Stebner, Colorado School of Mines