Review on study of internal load transfer in metal matrix composites using diffraction techniques

A systematic review of the various aspects of internal load transfer using different diffraction-based methods has been carried out in this work to strengthen the understanding of metal matrix composites (MMCs) and their micromechanics. The load transfer from the softer and more compliant metallic matrix to the harder reinforcement plays a major role in conventional MMCs with a relatively high volume fraction of reinforcement particles. The mechanism of load transfer is dependent upon several factors, and a thorough understanding of them is important to design MMCs with optimum properties. Advanced diffraction-based techniques, such as neutron diffraction and synchrotron X-ray diffraction, have been applied successfully to study internal load transfer in MMCs by several authors. These techniques have allowed the measurement of elastic lattice strains in all crystallographic phases of a bulk MMC. The phase stress can then be calculated from the measured lattice strain using standard elasticity relations. Evolution of both the lattice microstrain and stress in each crystalline phase as a function of the applied stress yields information about the deformation and damage within the composite material. This review gives an overview of the studies carried out so far on internal load transfer in MMCs and the insights obtained this way.