Multiaxial fatigue of an alumina particle reinforced aluminum alloy

Multiaxial fatigue tests were performed on thin-walled tubular specimens made of a particulate reinforced metal matrix composite-22% vol. Al2O3p 6061 Al with T6 heat treatment condition. Four types of strain-controlled, fully-reversed cyclic tests were investigated. They included: uniaxial; pure shear; equibiaxial in-phase; and 90 degrees out-of-phase loading paths. It is found that the conventional equivalent stress or equivalent strain criteria can only correlate individually the fatigue life of this metal matrix composite for each type of loading path. However, these parameters cannot be used for general multiaxial loading cases. In contrast, a total strain energy density parameter does correlate, very well, with the test results of all four types of loading paths by a unique strain energy-fatigue life curve. (C) 1998 Elsevier Science Ltd.