The analysis of internal strains measured by neutron diffraction in Al/SiC metal matrix composites

Neutron diffraction measurements of internal strain development during tensile loading are analysed so as to deduce the extent and mechanisms of load transfer taking place between matrix and reinforcement. It is demonstrated that the observed lattice strains in Al/20 vol.% SiC whisker and particulate composites can be understood largely in terms of an elastic transfer of load arising from the higher stiffness of the reinforcing phase, however at loads approaching a conventional 0.2% yield stress, plastically induced stresses also become important. Furthermore, in the particulate composite there is clear evidence that stress relaxation mechanisms are also important. © 1992.