Features of primary damage by high energy displacement cascades in concentrated Ni-based alloys
Features of primary damage by high energy displacement cascades in concentrated Ni-based alloys
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DOI：
10.1063/1.4942533
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发表时间：
2016-02-28
影响因子：
3.2
通讯作者：
Stoller, Roger E.
中科院分区：
文献类型：
--
作者：
Beland, Laurent Karim;Lu, Chenyang;Stoller, Roger E.
Ni与Fe或Co的合金化已被证明可以减少离子辐照下的初级损伤产生。从Ni、NiFe和NiCo中1、10、20和40 keV碰撞级联的经典分子动力学模拟中也获得了类似的结果。在所有情况下，形成了不完美的堆垛层错四面体，1/3 111 Burgers矢量的故障环路，和1/2 110 Burgers矢量的滑动间隙环路的混合物，沿着与小固着点缺陷复合物和簇。主要通过三种机制减少伤害。首先，Ni-Co，Ni-Fe，Co-Co和Fe-Fe短程排斥相互作用比Ni-Ni相互作用更硬，这导致在从超音速弹道状态到音速状态的过渡期间损伤形成减少。这在很大程度上控制了最终缺陷的产生。其次，合金化降低了热导率，导致更长的热峰值寿命。相关联的退火减少了最终损伤的产生。这两种机制是特别重要的级联能量小于40千电子伏。第三，在较高的能量下，在合金中抑制了亚级联产生大缺陷团簇。一些挑战和限制有关的预测原子模型的合金在高能粒子辐照下进行了讨论。(C)2016 AIP Publishing LLC.
Alloying of Ni with Fe or Co has been shown to reduce primary damage production under ion irradiation. Similar results have been obtained from classical molecular dynamics simulations of 1, 10, 20, and 40 keV collision cascades in Ni, NiFe, and NiCo. In all cases, a mix of imperfect stacking fault tetrahedra, faulted loops with a 1/3 111 Burgers vector, and glissile interstitial loops with a 1/2 110 Burgers vector were formed, along with small sessile point defect complexes and clusters. Primary damage reduction occurs by three mechanisms. First, Ni-Co, Ni-Fe, Co-Co, and Fe-Fe short-distance repulsive interactions are stiffer than Ni-Ni interactions, which lead to a decrease in damage formation during the transition from the supersonic ballistic regime to the sonic regime. This largely controls final defect production. Second, alloying decreases thermal conductivity, leading to a longer thermal spike lifetime. The associated annealing reduces final damage production. These two mechanisms are especially important at cascades energies less than 40 keV. Third, at the higher energies, the production of large defect clusters by subcascades is inhibited in the alloys. A number of challenges and limitations pertaining to predictive atomistic modeling of alloys under high-energy particle irradiation are discussed. (C) 2016 AIP Publishing LLC.