Elasto-plastic deformation within diamond reinforced metals for thermal management

Diamond reinforced metals are developed for highly sophisticated heat sink applications. High power densities in power electronics or satellite laser optics demand composites combining the high thermal conductivity of carbon diamond with formability of metals. The mismatch in thermal expansion and Young's moduli between particles and matrix are responsible for high micro stresses under operational conditions, which lead to interface delamination and thermal fatigue damage. Therefore, the interface bonding strength and ductility of the matrix determine the long term stability of such composites. The micro-mechanic deformation behavior was investigated by neutron diffraction combined with acoustic emission measurements non-destructively. The bonding quality, reinforcement architecture and deformation behavior could be revealed for aluminum- and silver-matrix composites under comparable conditions. Conclusions on the applicability of such composites for thermal management applications are drawn.127