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Effects of vacancies on the mechanical properties of zirconium: An ab initio investigation.

Authors :
Zhu, Xueyan
Gao, Xingyu
Song, Haifeng
Han, Guomin
Lin, De-Ye
Source :
Materials & Design. Apr2017, Vol. 119, p30-37. 8p.
Publication Year :
2017

Abstract

The irradiation-induced defects strongly influence the mechanical behaviors of zirconium (Zr) and its alloys in nuclear reactors. In this work, we focus on how the vacancies change the mechanical properties of α-Zr through density functional theory (DFT) calculations. Both uniformly distributed vacancies and vacancy clusters were considered. And a wide range of vacancy concentrations from 0.005 to 0.063 (molar fraction) was modeled. The most stable configurations of di- and trivacancy clusters were predicted, which correspond to the most compact distribution of vacancies. Mechanical properties were explored in terms of single-crystal elastic constants, based on which the polycrystalline elastic moduli, Pugh's ratio for ductility and Vickers hardness were derived. Our results show that the existence of uniformly distributed vacancies can reduce the ductility, while enhance the hardness in general. However, when the vacancy concentration is larger than a critical value, a rise in the ductility and a reduction in the hardness occur, which may contribute to the degeneration of the material. Compared with the uniform distribution of vacancies, clustering of vacancies strengthens the above changes of ductility and hardness. Moreover, it was found that the anisotropy of Young's modulus decreases with increasing vacancy concentration. [ABSTRACT FROM AUTHOR]

Details

Language :
English
ISSN :
02641275
Volume :
119
Database :
Academic Search Index
Journal :
Materials & Design
Publication Type :
Academic Journal
Accession number :
121454889
Full Text :
https://doi.org/10.1016/j.matdes.2017.01.060