An investigation was made of an elementary process of shock response of grain boundaries using molecular dynamics simulations: shock compression and spallation in Pd bicrystals with a symmetrical Σ5/(210)/<100> grain boundary. The loading direction was normal to the grain boundary. An elastic shock may induce the elastic-plastic or two-wave structure at the grain boundary. The serves as a wave scattering center for the transverse motion perpendicular to the grain boundary rotation axis and the shock direction: it induces a phase shift of 180∘, an increase in the amplitude of the particle velocity, grain boundary sliding and grain orientation distortion. The grain boundary was the preferred nucleation site both for dislocations and voids. The results suggested that both microstructure and the loading geometry contribute to dynamic response of a solid.

Shock Compression and Spallation of Palladium Bicrystals with a Σ5 Grain Boundary. H.H.Pham, B.Arman, S.N.Luo, T.Çağin: Journal of Applied Physics, 2011, 109[8], 086107