Effect of Dynamic Strain Aging on Fracture in Aluminum Alloy Sheet Materials AA5754

摘要

Solid-solution alloys such as Al-Mg alloy AA5754 often display serrated flow during tensile deformation due to dynamic strain aging over a range of temperatures and strain rates. The effect of dynamic strain aging on fracture properties has been an important concern in addition to surface quality and formability. In this paper, we present the results for double-edge-notched samples tested at room temperature. Digital image correlation was utilized to follow the deformation pattern during the tensile processes. The results show that the plasticity bursts are not limited to the notch tip causing the plastic zone to be finger-like. This cannot be predicted using conventional elastic-plastic fracture models. The results show that the fracture strain increases with increasing strain rate. We have also used 45 degree offset-edge notched samples also tested at room temperature. The results here show that the ductile crack propagates along the original crack line leading to the final failure.