Two-dimensional vacancy platelets as precursors for basal dislocation loops in hexagonal zirconium

Si-Mian Liu; Irene J Beyerlein; Wei-Zhong Han

doi:10.1038/s41467-020-19629-5

Two-dimensional vacancy platelets as precursors for basal dislocation loops in hexagonal zirconium

Nat Commun. 2020 Nov 13;11(1):5766. doi: 10.1038/s41467-020-19629-5.

Authors

Si-Mian Liu¹, Irene J Beyerlein², Wei-Zhong Han³

Affiliations

¹ Center for Advancing Materials Performance from the Nanoscale, State Key Laboratory for Mechanical Behavior of Materials, Xi'an Jiaotong University, 710049, Xi'an, China.
² Mechanical Engineering Department, Materials Department, University of California, Santa Barbara, CA, 93106-5070, USA.
³ Center for Advancing Materials Performance from the Nanoscale, State Key Laboratory for Mechanical Behavior of Materials, Xi'an Jiaotong University, 710049, Xi'an, China. wzhanxjtu@mail.xjtu.edu.cn.

Abstract

Zirconium alloys are widely used structural materials of choice in the nuclear industry due to their exceptional radiation and corrosion resistance. However long-time exposure to irradiation eventually results in undesirable shape changes, irradiation growth, that limit the service life of the component. Crystal defects called <c> loops, routinely seen no smaller than 13 nm in diameter, are the source of the problem. How they form remains a matter of debate. Here, using transmission electron microscopy, we reveal the existence of a novel defect, nanoscale triangle-shaped vacancy plates. Energy considerations suggest that the collapse of the atomically thick triangle-shaped vacancy platelets can directly produce <c> dislocation loops. This mechanism agrees with experiment and implies a characteristic incubation period for the formation of <c> dislocation loops in zirconium alloys.