Hydrogen-induced defects and multiplication of dislocations in Palladium

被引：17

作者：

Cizek, J. ^{[1
]}

Melikhova, O. ^{[1
]}

Prochazka, I. ^{[1
]}

机构：

[1] Charles Univ Prague, Fac Math & Phys, CZ-18000 Prague 8, Czech Republic

来源：

JOURNAL OF ALLOYS AND COMPOUNDS | 2015年 / 645卷

关键词：

Palladium; Hydrogen; Defects; Positron annihilation; Hardness; VACANCY; METALS;

D O I：

10.1016/j.jallcom.2014.12.155

中图分类号：

O64 [物理化学（理论化学）、化学物理学];

学科分类号：

070304 ; 081704 ;

摘要：

In the present work positron lifetime spectroscopy was employed for investigation of hydrogen-induced defects in Pd. Well annealed polycrystalline Pd samples were electrochemically charged with hydrogen and the development of defects with increasing hydrogen concentration was investigated. At low concentrations (alpha-phase region, x(H) < 0.017 H/Pd) hydrogen loading introduced vacancies surrounded by hydrogen atoms and characterized by a positron lifetime of approximate to 200 ps. When the hydrogen concentration exceeded 0.017 H/Pd the alpha-phase transformed into the hydrogen rich alpha'-phase. This generated dislocations characterized by a positron lifetime of approximate to 170 ps. Dislocations can accommodate a large volume mismatch between the alpha and the alpha'-phase. Hardness testing revealed that absorbed hydrogen made Pd harder. In the alpha-phase region hardness increased due to solid solution hardening caused by dissolved hydrogen. Dislocations created by the alpha to alpha'-phase transition caused strain hardening which led to an additional increase of hardness. (C) 2015 Elsevier B.V. All rights reserved.

引用

页码：S312 / S315

页数：4

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