Effects of Notch Radius and Thickness on the Tensile Strength and Fracture Mechanisms of Al6061-T6 Plate Specimens

In this study, the tensile strength and fracture mechanisms of Al6061-T6 plate specimens were evaluated based on von Mises stress and triaxial tensile stress according to the specimen geometry. Stress states at four representative sites (center, position of the maximum stress triaxiality, skin, and notch tip) on the cross-section of the gauge portion were analyzed under tensile testing. The notch strength ratios of specimens with a small notch radius significantly increase with an increase in thickness, whereas those of specimens with a large notch radius change very little. The intensity and position of the maximum stress triaxiality change significantly with varying notch radii and thicknesses. Consequently, with an increase in the thickness and decrease in the notch radius, the shear fracture mode transforms into a tensile-shear mixed fracture mode through the evolution of the stress state and plastic deformation.

Automated summary

This study evaluated the tensile strength and fracture mechanisms of Al6061-T6 plate specimens based on von Mises stress and triaxial tensile stress. The results showed that the notch strength ratios and stress triaxiality vary significantly with different notch radii and thicknesses, leading to a transformation from shear fracture mode to a tensile-shear mixed fracture mode.