Conclusions
Due to their lightweight, magnesium alloys are very attractive materials
for transportation industry. Therefore, un understanding of fracture
behavior of these alloys is essential. Notches are unvoidable and their
presence possess a risk against structural integrity of machines. The
quasi-static fracture of ZK60-T5 magnesium extrusion has been
investigated for U and V notched specimens. The followings summarize the
major outcomes of this research:
- Mechanical tests show that the notch acuity is inversily related to
the ductility
- Fractographic observations indicate that the material exhibits fibrous
and shear failure mechanisms that are common in ductile materials.
- The FE-SEM fractographies confirm that increasing the notch acuity
reduces the ductility as shown by the reduction of the shear lips size
with the increase in the notch acuity
- Observed secondary cracks are attributed to the presence of high
stress field near the notch tip and due to stress triaxiality.
- The strain energy density criterion was successfully used to estimate
the fracture load of U and V notched specimens with different sizes
and geometries.