Work hardening of dispersion-hardened crystals

Abstract A new theory of work hardening in dispersion-hardened single crystals—by which we mean soft crystals containing hard non-deforming particles of a second phase—is described. It is based on the fact that, if the particles do not deform plastically, and the interface between particle and matrix does not fracture, then secondary slip must occur locally round each particle when the crystal is deformed, even though the crystal may appear to deform by ‘single slip’. The density of secondary dislocations rises steeply with strain, and acts as a forest impeding the movement of primary glide dislocations. The theory predicts a relation between stress and strain (eqn. (9)) which is in good agreement with experimental results. Fracture of the particle-matrix interface, and the importance of the strength of this interface, are discussed.