Mechanical Properties and Fracture Toughness Behavior of Cold Worked AA 5754 Alloy

Abstract

In this present investigation, aluminum AA5754H111 alloy are coldworked to different reduction percentage (30%, 50% and 80%) at ambient temperature to establish effect of cold working on mechanical properties and fracture toughness of AA5754H111. The mechanical properties are studied by tensile test. The fracture toughness behavior is investigated by fracture toughness tests according to ASTME 1820 standard utilizing CCP (central cracked panels) specimens. The fracture toughness tests were performed to define the crack-tip opening displacement at resistance curve (CTOD-R) of starting and cold worked AA5754H111 alloy. Experiment results proved that the cold working has a profound effect on the mechanical tensile properties and fracture toughness parameter (resistance at crack initiation CTOD0.2) of AA5754H111 aluminum alloy. The accumulation of cold working enhances the work hardening impact, which is an excellent an agreement with the improvement of the tensile strength (ultimate tensile UTS and yield strength YS) and low the fracture toughness behavior (tenacity at crack initiation CTOD0.2) and plasticity (ductility). This is attributed to the significantly enhance of the density of dislocations and the severely elongation of the equiaxed grains through the rolling direction. Increase in tensile strength and decrease of fracture toughness parameter modified the fracture from ductile to brittle.