Effects of void fraction on void growth and linkage in commercially pure magnesium

Abstract

Void growth and linkage in magnesium is strongly influenced by the local microstructure. An innovative approach is used which allows for a quantitative analysis of the microstructural features that play a significant role in the deformation and fracture processes. Several hole configurations were investigated in order to determine the effects of void fraction on the growth and linkage processes. The samples were pulled in uniaxial tension under both an optical microscope and SEM. The digital image correlation method was used to obtain strain distributions. Furthermore, the experimental results were compared to crystal plasticity finite element simulations in order to determine the role of the various deformation mechanisms on the fracture behavior. It was established that the void fraction did not have a significant impact on the growth and linkage behavior of the holes. Interactions between the holes and the microstructure were observed for all of the configurations analyzed. The strain distributions revealed that twin and grain boundaries produce strain concentrations an order of magnitude larger than the macroscopic strain. Furthermore, the results show that there is likely a critical strain required to initiate fracture in these boundaries.