Fatigue Behavior of Al‐Cu Alloy Subjected to Different Numbers of ECAP Passes

Abstract

The cast alloy Al-0.63wt.% Cu was subjected to different number of equal channel angular pressing (ECAP) passes. Fatigue properties and shear bands on the surface of the alloy after fatigue were investigated. It is found that the ECAPed Al-Cu alloy displays obvious cyclic softening. Meanwhile, multipass ECAP treatment can decrease the shape parameter of hysteresis loops, indicative of a large Bauschinger effect. It is shown that the shear bands orient at about 45° with respect to the cyclic load axis. The current research proves that there is no one-to-one relationship between the shear bands induced by fatigue and the shear plane of the last ECAP extrusion, and the orientation of shear bands under fatigue should be parallel to the maximum shear stress plane of the specimen. In addition, it is noted that fatigue cracks can also occur in the area away from shear bands at low number of ECAP passes.