在局域密度泛函理论的基础上,采用第一性原理的平面波赝势方法,计算了纯铝晶界及掺杂钛和硅后的弛豫原子结构,分析和研究了钛、硅杂质偏析对铝晶界的影响.结果表明:杂质钛的偏析使晶界略有膨胀,晶界处的电子密度明显增加,硅的偏析使晶界收缩,晶界处电荷密度明显增加.但两种掺杂元素的偏析均形成了较强的具有共价-金属混合性质的化学键,局域的强化学键会抑制或削弱材料的位错形成和延展特性,从而按照"bond mobility model"机制阻止了应力作用下的原子重组.
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