Influence of particle content on the ductility of extruded non-recrystallized aluminium alloys subjected to shear loading

Abstract

In-plane shear tests were conducted on two extruded 6000-series aluminium alloys to investigate the influence of constituent particles on ductile fracture. The two alloys have previously been characterized and found to have different area fraction of constituent particles while having similar grain structure, crystallographic texture, strength, and work hardening. Specimens of both alloys were machined from flat profiles with their gauge section oriented along either the extrusion direction or the transverse direction. The specimens were loaded in shear until fracture and an experimental-numerical approach was employed to analyse the stress and strain fields, which involved digital image correlation and crystal plasticity finite element analysis. The fracture mode was determined by examining digital images captured during the experiment, while the fracture surface of representative specimens was examined in a scanning electron microscope. The shear strain across the gauge section at failure was substantially lower for the alloy with higher fraction of constituent particles, and the negative effect of the particle content on the ductility was found to be more pronounced for the tests in the transverse direction. The crystal plasticity finite element analyses showed an extensive texture development within the gauge region and that the local shear strain at failure was somewhat different in the two loading directions.