Atomistic Simulation Of Microstructure Evolution 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 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 eight types of crack, including (1210)[1010],(1010)[1210],(1210)[0001],(0001)[1210],(1011)[1012],(1012)[1011],(1010)[0001] and (0001)[1010], with different crack planes. The influence of the temperature on crack propagation is also considered.The results show that: the main deformation mechanisms of the crack tip in magnesium single crystal are dislocation, twinning, slip and stacking fault. The crack with different crack plane has different deformation behavior. Thus the orientation of cracks have great influence on the deformation mechanisms of the crack. In addition, we notice that the temperature also affects the deformation of the crack tip obviously, especially for (1210)[0001],(10011)[1012]and (1012)[1011]cracks.