论文标题
基础位错的相互作用与MGZN $ _2 $沉淀在mg合金中的原子模拟
Atomistic simulations of the interaction of basal dislocations with MgZn$_2$ precipitates in Mg alloys
论文作者
论文摘要
Mg边缘基础位错与杆状$β_1'$ -MGZN $ _2 $沉淀之间的相互作用是通过使用新的原子间潜力的原子模拟来研究的。考虑到有关基质与沉淀之间的方向关系的实验信息，仔细地建立了原子模型，以确保最小的能量接口。发现脱位最初是通过渗透在沉淀物中的Orowan环的形成来克服了沉淀物的。在堆积几个Orowan环后，最终将沉淀物剪切。随着沉淀的横截面降低，温度升高，剪切沉淀物所需的环数减少，但与沉淀间距无关。沉淀物剪切没有沿明确定义的晶体学平面进行，而是由弹性能在沉淀物中的积累触发的，最终导致基础位错上下方和上方的无定形层形成。通过这种机制在沉淀物中诱导的扭结与透射电子显微镜观测值非常吻合。
The interaction between Mg edge basal dislocations and rod-shaped $β_1'$-MgZn$_2$ precipitates was studied by atomistic simulations using a new interatomic potential. The atomistic model was carefully built taking into account the experimental information about the orientation relationship between the matrix and the precipitate to ensure minimum energy interfaces. It was found that the dislocations initially overcame the precipitate by the formation of an Orowan loop that penetrated in the precipitate. The precipitate was finally sheared after several Orowan loops were piled-up. The number of loops necessary to shear the precipitate decreased as precipitate cross-section decreased and the temperature increased but was independent of the precipitate spacing. Precipitate shearing did not take place along well-defined crystallographic planes but it was triggered by the accumulation of the elastic energy in the precipitate which finally led to formation of an amorphous layer below and above the slip plane of the basal dislocations. The kink induced in the precipitate by this mechanism was in good agreement with transmission electron microscopy observations.
