The Bauschinger effect in a particulate reinforced Al alloy

An experimental characterization of the Bauschinger effect in a particulate reinforced Al alloy revealed two important features: (1) the magnitude of permanent softening was small; (2) transient softening was significant and developed non-linearly with plastic strain. The Bauschinger effect (and associated internal stress) in these materials is dominated by relaxation processes which include plastic flow in the matrix and damage accumulation. Consequently internal stress is limited in its magnitude and develops only at low strains. The non-uniform particle distribution contributes to the inhomogeneous deformation occurring in the composite, leading to the large transient softening effect observed. A simple model used to describe stress partitioning between the two phases was successful in describing qualitatively the non-linear development of internal stress observed experimentally.