Tantalum is a body-centered-cubic (BCC) metal that is widely used in many industrial applications. In some of these applications, the material is subjected to extensive volumetric expansion, leading to ductile damage and failure. Therefore, understanding dynamic ductile damage behavior is particularly important. In order to reliably represent this failure process, a satisfactory constitutive model must provide an appropriate description of physics at a sufficient level of detail. However, the salient physics of ductile damage evolution in BCC materials such as tantalum is not well understood. This is because ductile damage is a consequence of several competing, irreversible mechanisms which operate at the microstructural to mesoscale. For example, in BCC metals, the ambiguity in the activated slip systems and non-Schmid effects complicate the effort to understand and represent the ductile damage process. We present our work towards understanding ductile failure in tantalum through mesoscale simulations. We consider a cubic unit cell of tantalum single crystals and polycrystals which explicitly includes voids. Under tensile loading, the unit cell is expanded. The solid crystal is extensively deformed toward growing voids in order to accommodate the large volumetric strain and relieve the macroscopic hydrostatic stress. The solid crystal is modeled with our previously published single crystal plasticity model for tantalum, which we have extended to address extensive plastic deformation at high rate and high temperature. We will present our preliminary results on the roles of crystal orientation, shear stress components, void size and distribution on dynamic ductile damage process, and discuss their implication on constructing a continuum ductile damage model across physical scales.
2025-04-09 09:00:00
