Formation of stacking-fault tetrahedra in aluminum irradiated with high-energy particles at low-temperatures
Formation of stacking-fault tetrahedra in aluminum irradiated with high-energy particles at low-temperatures
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DOI：
10.1103/physrevb.69.094108
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发表时间：
2004-03
影响因子：
3.7
通讯作者：
Y. Satoh;T. Yoshiie;H. Mori;M. Kiritani
中科院分区：
文献类型：
--
作者：
Y. Satoh;T. Yoshiie;H. Mori;M. Kiritani
层错四面体（SFT）是面心立方金属中典型的空位团簇。然而，SFT一直被认为是不稳定的铝，因为它的高堆垛层错能，直到最近发现的SFT在薄铝箔受到拉伸断裂。这项研究证实，SFT形式的铝与高能粒子辐照后。在电子辐照下，在203 K以下形成平均尺寸为2 nm的SFT，而在较低温度下较大的辐照强度诱导具有较大的数密度的SFT。用60 keV Al +离子辐照在室温以下引起SFT，尽管缺陷产率（缺陷团簇数目与入射离子数目的比率）约为10 - 3，远小于其它面心立方纯金属。当中子辐照温度低于15 K，注量为2 × 1021中子·m - 2时，在室温下未观察到SFT。相反，观察到位错环的形成和消失，在120千伏的电子，不引起原子位移的观察。铝箔的拉伸断裂在400 K以下发生SFT，这接近于等时退火实验中SFT变得不稳定的温度。这些结果表明，在较低的温度下，高浓度的空位往往会导致SFT的形成，而不是空位型位错环在铝。
Stacking-fault tetrahedra (SFT) are typical vacancy clusters in fcc metals. SFT have been, however, considered to be unstable in aluminum because of its high stacking-fault energy, until the recent finding of SFT in thin aluminum foils subjected to a tensile fracture. This study confirmed that SFT form in aluminum following irradiation with high-energy particles. In electron irradiation, SFT with an average size of 2 nm formed below 203 K, while a larger irradiation intensity at lower temperature induced SFT with a larger number density. Irradiation with 60-keV Al + ions induced SFT below room temperature, although the defect yield (the ratio of the number of defect clusters to the number of incident ions) was about 10 3 , considerably smaller than that in the other fcc pure metals. With neutron irradiation below 15 K to a fluence of 2 × 10 2 1 neutrons m - 2 , SFT were not observed at room temperature. Instead, dislocation loops were observed to form and to disappear during observation with 120-kV electrons that do not cause atomic displacements. Tensile fracture of aluminum thin foil induced SFT at up to 400 K, which is close to the temperature at which SFT become unstable in isochronal annealing experiments. These results suggest that a high concentration of vacancies at lower temperature tends to cause SFT to form rather than vacancy-type dislocation loops in aluminum.