Positron annihilation study of vacancy-type defects in high-speed deformed Ni, Cu and Fe
Positron annihilation study of vacancy-type defects in high-speed deformed Ni, Cu and Fe
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DOI：
10.1016/s0921-5093(02)00705-0
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发表时间：
2003-06-15
期刊：
影响因子：
6.4
通讯作者：
Kiritani, M
中科院分区：
文献类型：
--
作者：
Ohkubo, H;Tang, Z;Kiritani, M
本文用正电子湮没技术系统地研究了Ni、Cu和Fe中高速和低速形变引起的空位和空位团，并与常规轧制引起的空位和空位团作了比较。为了阐明缺陷的性质，将实验结果与我们对空位团簇中正电子寿命随其大小变化的叠加原子电荷计算进行了比较。结果表明，面心立方和体心立方金属中的形变诱导缺陷。明显不同。在Ni和Cu的fcc金属中，高酸低速变形和重常规轧制诱导了具有高数量密度的单空位（Ni>10%，Cu>40%）。观察后的高速和低速变形的Ni和常规轧制后的Cu的空位簇：相反，位错和空位簇引入bcc Fe的类型或程度的变形。(C)2002 Elsevier Science B.V.保留所有权利。
Vacancies and vacancy clusters in Ni, Cu, and Fe induced by high- and low-speed deformations are studied systematically by positron annihilation techniques and are compared with those induced by the conventional-rolling. To clarify the nature of the defects, the experimental results are compared with our superimposed-atomic-charge calculations of the positron lifetimes in the vacancy clusters as a function of their size. It is found that the deformation-induced defects in the fcc and bcc metals are. significantly distinct. In the fcc metals of Ni and Cu, monovacancies with high number densities are induced by the high- acid low-speed deformations and by heavy conventional-rolling ( >10% in Ni and >40% in Cu). Vacancy clusters are observed after the high- and low-speed deformation for Ni and after the conventional-rolling for Cu: On the contrary, dislocations and vacancy clusters are introduced in bcc Fe regardless of the type or degree of deformation. (C) 2002 Elsevier Science B.V. All rights reserved.