Debond Growth Behavior of Al/Epoxide Moulded Interface by Fatigue

Abstract

Fatigue tests were conducted on the moulded joints of aluminum and an epoxide adhesive material, and the debond growth behavior at its moulded interface pretreated in two different ways was observed. As the basic data, the fatigue crack propagation characteristics of the adhesive itself were experimentally obtained. The debond growth behavior at the interface by fatigue was predicted under the following conditions;
(1) The stress intensity factor of an interface crack is approximately equal to that of a crack in homogenious material as derived from the no-slip model proposed by Mak et al.¹⁾.
(2) The debond growth rate per cycle is equal to the crack propagation rate of the adhesive material.
(3) The residual stress on the moulded interface estimated by a photoelastic experiment and FEM analysis is taken into account as an influential factor for the stress ratio of fatigue load.
Fairly good agreement between the experimental and analytical results was found for the interface pretreated with sand-blast and chromic-acid. However the debond growth rate for the interface with no chromic-acid pretreatment was faster nearly by a factor of one order of magnitude than the prediction. Microscopic analyses of the debonded interfaces were conducted with SEM and X-ray microanalyzer and the debond growth mechanism was discussed.