Effect of Interface Roughness and Orientation on Shock Deformation in Bimetallic Microstructures

During shock deformation, the microstructural characteristics of multi-phase materials, particularly bimetal interfaces, play a critical role in determining their failure mechanisms. These interfaces significantly influence the evolution of dislocations and twinning, thereby impacting their spall strength. Despite their importance, a substantial knowledge gap exists between observed material behavior and the effects of interface roughness and orientation. This gap limits efforts to design robust, high-performance components for use in defense, energy, aerospace, and infrastructure sectors. To address this, we performed large-scale Molecular Dynamics (MD) shock simulations for Al-Ti bimetal interfaces to investigate their role in shock deformation. Specifically, this study examines how interface roughness affects material behavior under shock loading. Microstructures with flat interfaces and varying fractions of Al and Ti revealed that while the percentage of Ti and Al has minimal influence on peak compressive stress, it significantly affects spall strength. Moreover, the introduction of waveform interfaces reduces peak tensile stress compared to the flat interface. Additionally, we proposed a novel approach to model oblique shock, allowing us to examine the role of interface orientation relative to the loading direction. This sheds light on how oblique shock influences deformation mechanisms, offering valuable insights for optimizing bimetal microstructures. LA-UR-25-20734