Homogenization of an Al-Mg alloy and alligatoring failure: Alloy ductility and fracture

Abstract

High-strength Al-Mg alloys have a propensity toward hot fracture and failure by alligatoring during hot rolling. In this study the effect of homogenization conditions on the susceptibility of an Al-5.1Mg-0.7Mn alloy toward alligatoring was investigated. It was found that the plates homogenized in a temperature range of 460-520 °C were prone toward alligatoring, but once homogenized at 550 °C they were not prone toward it any longer. The characterization of the fracture showed a predominance of the intergranular ductile fracture, but the type of the constitutive particles filling the voids changed with the homogenization regime. Grain decohesion and grain-boundary embrittlement show that certain thermal treatments resulted in a microstructure that promoted slip localization.