Temperature Effect on the Deformation Behavior in Nanocrystalline Magnesium under Compression: An Atomistic Study

The classic molecular dynamics (MD) simulation approach has been used to investigate the microstructure change in polycrystalline magnesium (Mg) during compressive deformation at various temperatures. At low temperatures, there exists a competition between the sliding of Shockley partial dislocation (SPD) and perfect <a> dislocation. Abundant dislocation behaviors such as dislocation bundle and double cross slipping are observed. With a temperature increase, the dislocation sliding is hindered by the newly formed grain boundaries (GBs). The grain reorientation should be the compensatory mechanism for plastic deformation at high temperatures. Furthermore, dynamic recrystallization (DRX) is found at the highest temperature investigated. For all the temperature cases studied, twinning is unsensitive against applied compressive stress. The results of this work may help to understand the temperature effect on the mechanism in polycrystalline Mg under compressive deformation.