Interaction of displacement cascades with {10 1‾2} and {10 1‾1} twin boundaries in zirconium: A molecular dynamic study

Abstract

Twinning is a significant deformation mode in zirconium (Zr). Here we investigated the primary displacement cascades near the twin boundary (TB) and mechanical properties in Zr using molecular dynamics simulations. The results show that {10 1‾2} and {10 1‾1} TBs can act as an effective sink for point defects to enhance irradiation resistance in Zr. The {10 1‾2} TB exhibits better sink efficiency than {10 1‾1} TB. Hence, it's recommended to employ Zr alloys with more {10 1‾2} deformation twinning microstructure in irradiation conditions. The present work predicts the introduction of TBs may contribute to a decrease in the density of large-sized clusters and clustered fraction. Further, irradiation leads to localized deformation of the two TBs even in one single collision cascade. The tensile loading of the unirradiated and irradiated samples indicates that the stacking faults serve as an important deformation mechanism in two TB models. The results not only present a reference for understanding the TB structure in the displacement cascades of Zr and its alloys but also provide further support for the design of irradiation-resistant nanotwinned metals.

Keywords

• Zirconium
• Twin boundary
• Displacement cascade
• Mechanical properties
• Molecular dynamics simulations