Effect of in-plane constraint on mechanical behaviour of a metallic composite in biaxial stress states

This investigation focuses on the effect of in-plane constraint, which is a measure of the hydrostatic tension at the plane stress condition, on the y ielding, fracture and fatigue of thin-walled tubes of an alumina particle-r einforced 6061 aluminium alloy composite. The results are compared with tha t of the unreinforced alloy. The yield surface radius of the particulate re inforced metal matrix composite (PMMC) is larger than that of the alloy in all loading paths. The fracture strength of the PMMC in terms of equivalent stress value is less sensitive to the change of the in-plane constraint of biaxial loading than that of the unreinforced alloy. The fatigue lives of the composite under the same equivalent strain decrease with the increase o f the in-plane constraint factor, but by a lesser amount in comparison to t hat of the alloy. (C) 2000 Elsevier Science Ltd. All rights reserved.