论文标题
锆石中<c+a>位错的迁移率
Mobility of <c+a> dislocations in zirconium
论文作者
论文摘要
六角形封闭式锆的可塑性主要由1/3 <1-210>汉堡矢量的位错的滑动控制。由于这些位错无法在[0001]方向上适应变形，因此必须激活带有1/3 <1-213>汉堡矢量的<c+a>位错的孪生或滑动。我们已经在透射电子显微镜中进行了原位过滤实验，以研究在室温下在两个不同的锆样品（纯锆和锆-4）中<c+a>位错的滑动。这些实验表明，<c+a>位错仅在一阶锥体平面上滑动，并激活交叉滑移。当它们的方向对应于通过滑动平面与基础平面的相交所定义的<a>方向时，一种更强的晶格摩擦与<c+a>脱位的滑动相反。这会导致长时间的脱位沿<a>粘着粘性或抽搐。这个方向控制了段的运动，其形状仅是由线张力的最小化驱动的。还讨论了由于溶质原子引起的摩擦。
Plasticity in hexagonal close-packed zirconium is mainly controlled by the glide of dislocations with 1/3<1-210> Burgers vectors. As these dislocations cannot accommodate deformation in the [0001] direction , twinning or glide of <c+a> dislocations, i.e. dislocations with 1/3<1-213> Burgers vector, have to be activated. We have performed in situ straining experiments in a transmission electron microscope to study the glide of <c+a> dislocations in two different zirconium samples, pure zirconium and Zircaloy-4, at room temperature. These experiments show that <c+a> dislocations exclusively glide in first-order pyramidal planes with cross-slip being activated. A much stronger lattice friction is opposing the glide of <c+a> dislocations when their orientation corresponds to the <a> direction defined by the intersection of their glide plane with the basal plane. This results in long dislocations straightened along <a> which glide either viscously or jerkily. This <a> direction governs the motion of segments with other orientations, whose shape is merely driven by the minimization of the line tension. The friction due to solute atoms is also discussed.
