Atomistic Simulation Of Deformation Behavior At A Crack Tip In Magnesium Single Crystal

Magnesium alloys have attracted attention in recent years as lightweight materials for the transportation industry due to their low density and relatively high specific strength. In order to use magnesium alloys in structural applications, it is important to make sure that their mechanical properties meet both reliability and safety requirements. Due to the hexagonally close-packed (hcp) structure, the fracture toughness in magnesium alloys has generally been reported to be much lower than that in other alloys, such as face-centered cubic (fcc) or body centered cubic (bcc) metals and alloys. So it is very important to study the fracture of the magnesium alloys.Generally speaking, the fractures of the materials include macrofracture and microfracture. In the present paper, we use the molecular dynamics simulation to analyze the microfracture of the magnesium single crystal, which can describe the deformation of the crack tip very well. We select two types of crack (0001)[1010] and (1010)[0001] with different crack planes. Furthermore, the influence of the temperature, the length of the crack as well as the strain rate are considered.The results show that:the main deformation mechanisms of the crack tip in magnesium single crystal are twinning, slip and vacancy. The type of cracks, the temperature and the strain rate have great influence on the deformation mechanisms of the crack. The crack with different crack plane has different deformation behavior, and twinning is easier to occur at lower temperatures and higher strain rates. However, we notice that the length of the crack in the model doesn't affect the deformation of the crack tip obviously.