溶质偏析对Mg-Y-Zn合金层错能的影响

Effect of solute segregation on the stacking fault energy in Mg-Y-Zn alloys

为了有效地改善镁合金机械性能,通过基于密度泛函理论下的第一性原理计算,研究溶质原子(钇和锌)对Mg-Y-Zn合金层错能的影响。计算结果表明:钇和锌原子主要偏析在体系的层错层和层错邻层,并且由于溶质偏析造成了合金层错能显著降低。电子结构的研究表明:在镁和钇以及钇和锌之间形成的强烈的共价键是造成合金层错能显著降低的原因。目前国内外关于合金铃木效应的研究还不够完善,而通过计算机模拟,将以往有关铃木偏析现象的研究从单个原子单种元素扩展到了多种元素多个原子,能够提供有关合金铃木效应的更为深刻的视野与理解。

In order to effectively improve mechanical properties of magnesium alloys,the effect of solute atoms Y and Zn on stacking fault in Mg-Y-Zn alloys was studied by First-principles calculations based on density functional theory.The calculated results show that Y and Zn atoms preferentially segregate at the stacking fault layer and the adjacent layer,and the segregation results in significant decrease of the stacking fault energy.The electronic structure reveals that the stronger covalent bondings between Mg and Y and between Y and Zn are formed to lower the stacking fault energy dramatically.At present,the research about the Suzuki effect of alloy is still not enough.Through the computer simulation,the present investigations extend the single atom segregation of the previous work to co-segregation of more solute atoms and even to the co-segregation of two elements,providing a new insight into Suzuki effects of alloys would be provided.