Effect of pressure rolling on the residual stress state of a particulate-reinforced metal matrix composite

The large difference between the coefficients of thermal expansion of the matrix alloy and the particle in a metal matrix composite gives rise to residual stresses in the material. In the present work, the effect of pressure rolling on the residual stress state of a silicon carbide particle-reinforced 2014 aluminium alloy has been investigated. The three-dimensional stress state measured in both phases-matrix and reinforcement-has been determined using an X-ray diffraction technique. A twofold effect of pressure rolling on the residual stresses was observed. On the one hand, compressive macrostresses as large as - 250 MPa were induced. On the other hand a significant reduction in pseudo-macrostresses was measured where the plastic deformation reaches a maximum. A modified Eshelby model was used to predict quantitatively and qualitatively the residual microstresses after heat treatment and pressure rolling respectively.