Revealing the Effects of Strain and Alloying on Primary Irradiation Defects Evolution in Tantalum Through Atomistic Simulations

In this study, we employed molecular dynamics simulations to explore the influence of strain on primary defect formation and interstitial dislocation loop (IDL) development in pure tantalum (Ta) and Ta-20 W alloy systems under collision cascade events. The investigation considered primary knock-on atom (PKA) energies ranging from 5 to 30 keV at 30 K and subjected volumetric structures to six distinct strain values, encompassing both compressive and tensile strains. Our results revealed that the number of surviving Frenkel pairs (FPs) and self-interstitial atom (SIA) clusters increased with tensile strain and decreased with compressive strain, with the Ta-20 W alloy exhibiting the lowest observed numbers compared to pure Ta. Notably, SIA clusters in pure Ta were approximately double those in alloyed structures for clusters containing two to four atoms. We also observed that pure Ta systems displayed larger and longer IDL segments than alloyed Ta systems, which featured smaller and shorter IDLs. The applied strain was found to lower the barrier for IDL formation, potentially leading to material degradation. In conclusion, this study highlights the importance of considering the effects of strain and alloying in radiation-damaged environments, particularly in low-temperature, high-radiation-energy environments.

Automated summary

In this study, we used molecular dynamics simulations to investigate the impact of strain on defect formation and interstitial dislocation loop (IDL) development in pure tantalum and Ta-20 W alloy systems. The results showed that the number of Frenkel pairs (FPs) and self-interstitial atom (SIA) clusters increased with tensile strain and decreased with compressive strain, with the alloy system exhibiting lower numbers compared to pure tantalum. Additionally, the applied strain reduced the barrier for IDL formation. This study highlights the importance of considering strain and alloying effects in radiation-damaged environments.