Experimental Characterization and Theoretical Prediction of Quasi-Static
Fracture Behavior of Notched ZK60-T5 Mg Samples
Abstract
Magnesium and its alloys have increasingly gained attention among
practitioners and engineers due to their attractive properties,
specifically their high specific strength that renders these materials
suitable for several applications in different industries. However,
their use is still limited, especially in load-bearing applications, due
to the limited knowledge of their fracture behavior, especially in the
presence of notches. The aim of this work is thus that to fill this
lack, investigating the fracture behavior of notched ZK60-T5 magnesium.
Eleven different notch geometries were considered, i.e. U notched
specimens with notch radii of 1.5, 3, 4, 5, and 6 mm and V notched
specimens with notch opening angles of 35°, 60° and 90°, and notch radii
of 0.4 and 0.8 mm. The mechanical tests showed that the presence of
notches reduces the ductility of the material. This was confirmed also
by the fracture surface analyses carried out by means of Field Emission
Scanning Electron Microscope (FE-SEM), where the size of the shear lips
was shown to decrease by increasing the notch acuity. In addition, this
work aims also to provide practitioners and engineers with a tool able
to predict the failure loads irrespective of the notch geometry. For the
first time on Mg samples, a local approach, i.e. the Strain Energy
Density (SED), is used to predict the failure loads of the differently
notched samples, and the results suggest high reliability of this
approach, being the deviations between the experimental and the
theoretical data often lower than 10%.