Defect cluster configurations and mobilities in α-Zr: A comparison of the BMD19 and M07 interatomic potentials

• Published in: Journal of nuclear materials 2022-02, Vol.559, p.153441, Article 153441
• Main Authors: March-Rico, Jose F., Wirth, Brian D.
• Format: Article
• Language: English
• Subjects: Anisotropy; Basal plane; Burgers vector; c-loops; Clusters; Configurations; Critical components; Crystals; Defects; Diffusion; Dislocation loops; Interstitials; Irradiation growth; Molecular dynamics; Planes; Point defects; Vacancies; Zirconium
• ISSN: 0022-3115; 1873-4820
• DOI: 10.1016/j.jnucmat.2021.153441

Preferred defect cluster configurations and diffusion behavior are calculated with the recently published BMD19 interatomic potential for α-zirconium and compared with results calculated from the M07 potentials. Both potentials predict that small SIA clusters form configurations contained entirely within a single basal plane, while large SIA clusters form perfect dislocation loops on first-order prismatic planes with Burgers vector b→=13. The M07 potentials predict stable void formation for vacancy clusters while the BMD19 potential accurately indicates a preference for planar configurations on either first-order or second-order prismatic planes. Small basal vacancy clusters are found to form faulted pyramidal structures and only transform to faulted c-loops at larger sizes. In evaluating the defect diffusivity, single vacancies and interstitials are both found to exhibit anisotropic diffusion within the basal-plane. Small SIA clusters are found to migrate exclusively in 2-D within a single basal plane with the BMD19 potential but migrate in 3-D with the M07 #3 potential. Small vacancy clusters are either unstable or immobile with the M07 #3 and #2 potentials, while these clusters exhibit appreciable mobility either along the c-axis or in a quasi-isotropic manner with the BMD19 potential. The apparent difference in the diffusional anisotropies of defect clusters, rather than point defects, could be a critical component for improving predictive capabilities for mesoscale modeling of microstructural evolution in α-zirconium. •Defect cluster configurations and mobilities were investigated with MD simulations.•Faulted basal pyramids may act as pre-cursors to faulted c-loop formation.•Small SIA clusters are contained in one basal plane, and migrate sluggishly in 2-D.•Small vacancy clusters migrate either isotropically, or biased along the c-axis.•Difference in defect cluster anisotropy will result in rapid c-loop growth. [Display omitted]