Computer simulation of reactions between an edge dislocation and glissile self-interstitial clusters in iron
Computer simulation of reactions between an edge dislocation and glissile self-interstitial clusters in iron
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DOI：
10.1080/14786430600570527
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发表时间：
2006-09-01
影响因子：
1.6
通讯作者：
Rong, Z.
中科院分区：
文献类型：
--
作者：
Bacon, D. J.;Osetsky, Y. N.;Rong, Z.
自填隙原子（SIAs）团簇通过高能位移级联在金属中形成，通常以具有完美Burgers矢量B的小位错环的形式。本文用原子尺度的计算机模拟方法研究了应力作用下α-铁中刃型位错在B倾斜于位错滑移面时的反应。小环（这里有37个小环）的B自发地变化，并且光子被吸收为一对超阶跃。当产生一个或多个空位时，该线在临界应力τ（c）处向前滑动，并且凹凸部采用滑动形式。一个大的环（331个SIA）自发地与位错反应，形成一个B 100 hi的段，它在位错滑移面上是固着的，随着施加的应力增加，位错侧臂被拉成螺旋取向。在低温下（100 K），< 100 >段保持固着和位错最终打破自由时，螺旋偶极子臂交叉滑移和湮灭。在300 K及以上，该片段可以滑过环并将其转变为一对超级慢跑，在tau（c）处变得滑动。小的环是比具有类似数量的空位的空洞更弱的障碍，大的环更强。无论大小，相互作用的过程，导致superjogs是有效的SIA集群从滑移带的吸收，在流动本地化中观察到的效果。
Clusters of self-interstitial atoms (SIAs) are formed in metals by high-energy displacement cascades, often in the form of small dislocation loops with a perfect Burgers vector, b. Atomic-scale computer simulation is used here to investigate their reaction with an edge dislocation gliding in alpha-iron under stress for the situation where b is inclined to the dislocation slip plane. The b of small loops ( 37 SIAs here) changes spontaneously and the interstitials are absorbed as a pair of superjogs. The line glides forward at critical stress tau(c) when one or more vacancies are created and the jogs adopt a glissile form. A large loop ( 331 SIAs here) reacts spontaneously with the dislocation to form a segment with b 100 hi, which is sessile on the dislocation slip plane, and as applied stress increases the dislocation side arms are pulled into screw orientation. At low temperature (100 K), the < 100 > segment remains sessile and the dislocation eventually breaks free when the screw dipole arms cross-slip and annihilate. At 300 K and above, the segment can glide across the loop and transform it into a pair of superjogs, which become glissile at tau(c). Small loops are weaker obstacles than voids with a similar number of vacancies, large loops are stronger. Irrespective of size, the interaction processes leading to superjogs are efficient for absorption of SIA clusters from slip bands, an effect observed in flow localization.