低温下稀Al-Ag合金中正电子与Ag团簇相互作用机制的研究

Study of Interaction Mechanism between Positrons and Ag Clusters in Dilute Al-Ag Alloys at Low Temperature.

作者信息

Liu Xiaoshuang, Zhang Peng, Wang Baoyi, Cao Xingzhong, Jin Shuoxue, Yu Runsheng

机构信息

Institute of High Energy Physics, Chinese Academy of Sciences, Beijing 100049, China.

School of Nuclear Science and Technology, Chinese Academy of Sciences, Beijing 100039, China.

出版信息

Materials (Basel). 2021 Mar 16;14(6):1451. doi: 10.3390/ma14061451.

DOI:10.3390/ma14061451

PMID:33809744

原文链接:https://pmc.ncbi.nlm.nih.gov/articles/PMC8002228/

Abstract

The microstructural evolution of dilute Al-Ag alloys in its early aging stage and at low temperatures ranging from 15 K to 300 K was studied by the combined use of Positron annihilation lifetime spectroscopy (PALS), high resolution transmission electron microscopy (HRTEM), and positron annihilation Coincidence Doppler broadening (CDB) techniques. It is shown that at low temperatures below 200 K, an Ag-vacancy complex is formed in the quenched alloy, and above 200 K, it decomposes into Ag clusters and monovacancies. Experimental and calculation results indicate that Ag clusters in Al-Ag alloys can act as shallow trapping sites, and the positron trapping rate is considerably enhanced by a decreasing measurement temperature.

摘要

通过正电子湮没寿命谱（PALS）、高分辨率透射电子显微镜（HRTEM）和正电子湮没符合多普勒展宽（CDB）技术相结合的方法，研究了稀Al-Ag合金在其早期时效阶段以及15K至300K低温范围内的微观结构演变。结果表明，在200K以下的低温下，淬火合金中形成了Ag-空位复合体，而在200K以上，它分解为Ag团簇和单空位。实验和计算结果表明，Al-Ag合金中的Ag团簇可作为浅陷阱位点，并且随着测量温度的降低，正电子俘获率显著提高。