Study of High-Temperature Superconducting Material Radiation Damage Based on Molecular Dynamics under Uniaxial Strain

Abstract High-temperature superconducting (HTS) magnets are essential for numerous advanced technological applications, yet their performance can be significantly impacted by the challenging conditions of their operating environments. Significant attention has been devoted to understanding the behaviour of HTS materials under irradiation, but limited research has been conducted on their irradiation response under tensile strain—a condition frequently encountered in practical applications. In this study, molecular dynamics (MD) simulations were employed to investigate the effects of radiation damage on high-temperature superconducting materials under various strain conditions. The proton irradiation experiment on a curved tapes was conducted to qualitatively validate the simulation results. The effects of uniaxial strain within 5% on the threshold displacement energy of oxygen were analysed. The results reveal the average threshold displacement energy decreases with increasing strain, indicating an enhanced sensitivity to defect formation. At a strain of 3%, most threshold displacement energies are significantly reduced, experiencing decreases ranging from 30% to 40%. When the strain increases further to 5%, the threshold displacement energy shows a consistent reduction across nearly all directions for all atoms. The results of the irradiation experiments indicate that as the fluence increases, the disparity in critical current among HTS samples with different bending radii becomes increasingly pronounced. The critical current of samples with a smaller bending radius decreases more rapidly. Influenced by the degree of bending, the relative deviation in critical current between samples increases from approximately 0% to 40% as the fluence rises from 10¹⁴ p/cm² to 10¹⁶ p/cm². This study provides valuable insights into the radiation responds of HTS materials under stress and offers mechanistic support for potential changes in their properties during application.