Impact of microstructure on void growth and linkage in pure magnesium

The role of the microstructure on void growth and linkage in magnesium has been investigated. 2D model materials have been fabricated using pico-second laser technology whereby holes were drilled into the gage section of tensile samples composed of thin Mg sheet. These were pulled in uniaxial tension inside the chamber of an SEM which allowed for a quantitative assessment of the void growth and linkage processes. In contrast to the recent studies of void growth and linkage in fcc metals (copper and aluminum), the local microstructure plays a significant role on the deformation and fracture behavior of magnesium. Void growth was observed to occur non-uniformly due to interactions between the holes and microstructural features such as grain and twin boundaries. In addition, the main fracture mechanisms responsible for void linkage include failure associated with these boundaries. Twin and grain boundaries introduce microstructural features on a length scale comparable to the holes which are not present in models based on continuum mechanics. In order to model the deformation and fracture of magnesium, the initial microstructure as well as microstructural evolution must be taken into account.