Two- and three-dimensional characterizations of hot tears in a Al-Mg-Si alloy laser weld

Hot tears in 6xxx aluminium alloy laser welds are characterized. They are shown to be intergranular, originating from fracture of liquid films without plasticity of the surrounding grains. The hot tear initiates on both sides of the fusion zone, follows the liquid films between the columnar grains of the weld line and then propagates around the equiaxed grains of the fusion zone centre. By using three-dimensional X-ray tomography, the exact shape of the hot tears has been visualized. (c) 2008 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.