Alloying Mg with Gd and Y: Increasing both plasticity and strength

作者：Tang, Lingling; Liu, Wei^*; Ding, Zhigang; Zhang, Dalong; Zhao, Yonghao^*; Lavernia, Enrique J.; Zhu, Yuntian

来源：Computational Materials Science, 2016, 115: 85-91.

DOI：10.1016/j.commatsci.2016.01.003

• Magnesium alloys
• Plastic deformation
• Generalized planar fault energy
• Density-functional theory calculations

The addition of rare elements to Mg enhances mechanical behavior via solution and precipitation strengthening mechanisms. To provide fundamental insight into the underlying mechanisms, we apply density-functional theory (DFT) calculations to systematically study the generalized planar fault energy (GPFE) for pure Mg and its alloys with Gd, Y, and Gd-Y. Special attention is focused on the {0001}< 1 (1) over bar 100 > basal and {1 (1) over bar 00}< 1 (1) over bar 100 > prismatic slip systems. Our results show that the addition of Gd and Y in Mg significantly reduces the magnitude of GPFE, in particular for the {1 (1) over bar 00}< 11 (2) over bar0 > prismatic slip system. The analysis of the charge density distribution reveals that the predicted reduction in GPFE can be primarily attributed to a decrease of shear resistance between the slip planes. Based on the criterion for the anisotropy of the dislocation mobility and disembrittlement parameter, we demonstrate that alloying Mg with Gd and Y yields lower resistance to slip and hence an improvement in plasticity. Our results also suggest that the strength and plasticity of the Mg-Gd-Y system can be simultaneously enhanced due to charge transfer between Mg and alloying atoms.

• 出版日期2016-4-1
• 单位南京理工大学