Removal of stacking-fault tetrahedra by twin boundaries in nanotwinned metals
Removal of stacking-fault tetrahedra by twin boundaries in nanotwinned metals
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DOI：
10.1038/ncomms2382
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发表时间：
2013-01
影响因子：
16.6
通讯作者：
K. Yu;D. Bufford;Chengshuai Sun;Yue Liu;Haiyan Wang;M. Kirk;Matthew Li;Xinghang Zhang
中科院分区：
文献类型：
--
作者：
K. Yu;D. Bufford;Chengshuai Sun;Yue Liu;Haiyan Wang;M. Kirk;Matthew Li;Xinghang Zhang
堆垛层错四面体是具有面心立方结构的中子或质子辐照结构金属中的有害缺陷。它们的去除非常具有挑战性，通常需要在非常高的温度下退火、掺入间隙原子或与移动位错相互作用。在这里，我们提出了一种替代解决方案，用于去除在室温下发现的堆垛层错四面体，原位氪离子辐照外延纳米孪晶银，平均孪晶间距约为 8 nm。大量堆垛层错四面体在与丰富的相干孪晶边界相互作用期间被去除。因此，辐照纳米孪生银中堆垛层错四面体的密度远低于其块体对应物中的堆垛层错四面体密度。确定了两种基本的相互作用机制，并与分子动力学模拟的预测进行了比较。原位研究还揭示了一种新现象：辐射引起的相干和非相干孪生边界的频繁迁移。讨论了潜在的迁移机制。
Stacking-fault tetrahedra are detrimental defects in neutron- or proton-irradiated structural metals with face-centered cubic structures. Their removal is very challenging and typically requires annealing at very high temperatures, incorporation of interstitials or interaction with mobile dislocations. Here we present an alternative solution to remove stacking-fault tetrahedra discovered during room temperature,in situKr ion irradiation of epitaxial nanotwinned Ag with an average twin spacing of ~8 nm. A large number of stacking-fault tetrahedra were removed during their interactions with abundant coherent twin boundaries. Consequently the density of stacking-fault tetrahedra in irradiated nanotwinned Ag was much lower than that in its bulk counterpart. Two fundamental interaction mechanisms were identified, and compared with predictions by molecular dynamics simulations.In situstudies also revealed a new phenomenon: radiation-induced frequent migration of coherent and incoherent twin boundaries. Potential migration mechanisms are discussed.