Atomistic simulation of helium bubble nucleation in palladium

作者：Wang, Liang; Hu, Wangyu^*; Xiao, Shifang; Yang, Jianyu; Deng, Huiqiu

来源：Nuclear Instruments and Methods in Physics Research Section B: Beam Interactions with Materials and Atoms , 2009, 267(18): 3185-3188.

DOI：10.1016/j.nimb.2009.06.068

• Helium bubble
• Nucleation
• Atomistic simulation
• Cluster
• Molecular dynamics

A palladium crystal has been constructed with 11808 atoms. 55 helium atoms occupied the octahedral position of palladium crystal are introduced and retained in a spherical region. Molecular dynamic simulations are performed in a constant temperature and constant volume ensemble (NVT) with temperature controlled by Nose-Hoover thermostat. The interactions between palladium atoms are described with modified analytic embedded atom method (MAEAM), the interactions between palladium atom and helium atom are in the form of Morse potential, and the interactions between helium atoms are in the form of L-J potential function. With the analysis of the radial distribution RDF) and microstructure, it reveals that some of helium atoms form a series of clusters with different size, and the nucleation core is random at low temperature, and which is the embryo of helium bubble. Increasing temperature can accelerate the process of bubble nucleation, and the clusters will aggregate and coalesce into a bigger one in which there are no palladium atoms, and it is considered as a helium bubble.

• 出版日期2009-9-15
• 单位湖南大学; 湖南工程学院