2021-04-07 08:00:00
An analysis of the initiation and growth of voids in the Li electrode during the stripping phase of an Li-ion cell with a solid electrolyte is presented. We first show that standard Butler-Volmer kinetics fails to predict the observed void formation. This motivated us…
We have significantly extended a previous dislocation-density based constitutive theory to enable modeling the strong influence of temperature and strain rate on the thermomechanical behavior of single crystal body centered cubic (BCC) tantalum. The extension includes an expression of saturation dislocation density as a…
Lightweight magnesium (Mg) alloy sheets have attracted considerable attention for potential applications in transportation vehicles. However, their poor formability at room temperature (RT) hinders the wider applications. This work presents an advantage of precipitation-hardenable wrought Mg alloys in simultaneously achieving excellent RT formability and…
Magnesium alloys are an attractive material system for protection applications owing to their high specific strength and stiffness, but have low failure strains relative to similar strength lightweight metals in this application (e.g. Al, Ti). The plastic anisotropy from the low-symmetry HCP crystal structure…
Mechanical twinning is a form of permanent deformation that occurs in various crystalline solids, especially in low symmetry crystals, such as hexagonal close-packed (HCP) metals. The presence and formation of twins have been shown to have drastic effects on the strength and ductility of…
Ramp-driven compression-release experiments offer possibilities to explore material response under conditions distinct from those accessed by shock-driven loading conditions. For a material undergoing phase transformation, the problem of material model identification from experimental measurement is made substantially more complex by the need to untangle…
In this work, we present results from a combined numerical and experimental study aimed at investigating the role of competing mechanisms understood to govern dislocation glide in polycrystalline aluminum under ultra-high strain-rates and temperatures approaching the melting point. Pressure-and-shear plate impact (PSPI) experiments are…
As the application of magnesium (Mg) has increased significantly in the past decade, thanks to the high strength to density ratio, studies aiming to shed more light on its outstanding mechanical behavior have received attention. Several experimental and numerical studies suggest the Mg behavior…
High strength magnesium alloys such as WE43 are promising materials for lightweight physical protection systems for military and other applications. The high strain rate mechanical response of the material is critical for successful use in such roles, and this is less well understood for…
The mobility of dislocations is an important factor in understanding material strength. Dislocations experience a drag due to their interaction with the crystal structure, the dominating contribution at high stress and temperature being the scattering off phonons due to phonon wind. Yet, the functional…
