Uncovering microstructural heterogeneity effects of metal-matrix composites on dynamic instabilities and plastic shocks

Metal-Matrix Composites (MMCs) have great potential to replace monolithic metals in Energy Absorption Applications due to their enhanced properties such as high strength-to-weight ratio, higher operating temperature, and better wear resistance. However, despite their attractive mechanical properties, which allow to design durable, lightweight and stable structures [1], the utilization of MMCs to build protective systems has been limited primarily due to their relative low reliability, as the mechanisms controlling flow and fracture of these materials at high strain rates are largely unknown [1].

This is precisely the scientific gap to be filled in this project, in which a 4-years research effort of unprecedented magnitude has been specifically devised to identify the mechanisms which control the formation of instabilities and plastic shocks leading to fracture of ductile MMCs subjected to impact loading. This is a pending challenge in Solid Mechanics, which requires to derive a disruptive multidisciplinary and multiscale approach in which the latest advances in Manufacturing Engineering and Materials Science are put at the service of Continuum Mechanics to open new avenues in the design and analysis of protective structures. We have prepared a three-pronged approach –singular experiments, large scale computations and novel theories– to address 3 canonical dynamic fracture problems frequently used to assess the suitability of materials to absorb energy under impact: (1) spalling, (2) shear banding and (3) fragmentation. In MMCs the microstructure determines the fracture toughness through activation of different failure mechanisms under different loading conditions, so that the goal of UNCLOAK is to build up a self-contained research programme that culminates explaining the influence of microstructural heterogeneity on dynamic plastic localization and failure [1].