Shock compression of reactive powder mixtures

The shock compression of reactive powder mixtures can yield varied chemical behaviour with occurrence of mechanochemical reactions in the timescale of the high pressure state, or thermochemical reactions in the timescale of temperature equilibration, or simply the creation of dense packed highly reactive state of material. The principal challenge has been to understand the processes that distinguish between mechanochemical (shock induced) and thermochemical (shock assisted) reactions, which has broad implications for the synthesis of novel metastable or non-equilibrium materials, or the design of highly configurable next generation energetic materials. In this paper, the process of shock compression in reactive powder mixtures and the associated role of various intrinsic and extrinsic characteristics of reactants in the triggering of ultrafast shock induced chemical reactions are discussed. Experimental techniques employing time resolved diagnostics and results which identify the occurrence of shock induced reactions are reviewed. Conceptual and numerical models used to describe the heterogeneous nature of such reactions through mesoscopic details of shock compression are presented. Finally, a discussion of the application of recent results for the design of reactive material systems with controlled reaction initiation and energy release characteristics is provided.