Effect of interstitial carbon on the evolution of early-stage irradiation damage in equi-atomic FeMnNiCoCr high-entropy alloys

Abstract

Owing to their excellent radiation tolerance, some of the high-entropy alloys (HEAs) are considered as potential candidates for structural materials in extreme conditions. In order to shed light on the early-stage irradiation damage in HEAs, we performed positron annihilation spectroscopy on hydrogen implanted equi-atomic FeMnNiCoCr and interstitial carbon-containing FeMnNiCoCr HEAs. We reveal primary damage as mono-vacancies in low dose irradiated HEAs. The enhancement of Frenkel pair recombination by C addition is observed in C-containing HEAs. In addition, the C interstitials suppress the vacancy cluster formation in high dose irradiated HEAs.

Precipitation of supersaturated solute in H ion irradiated Fe-Au and Fe-Au-W alloys studied by positron annihilation spectroscopy

“…Experimentally, the formation of Cu-V complexes and vacancy-like defects surrounded by tiny Cu precipitates in Fe-Cu model alloys was detected by slow positron spectroscopy. In the previous study of hydrogen irradiated metal, also an effect of the alloying elements on the irradiated-induced defects was observed [19,20]. Also recent work on the hydrogen implanted C-containing FeMnNiCoCr high-entropy alloys demonstrated that the interaction between the interstitial C atoms and irradiated-induced vacancies will inhibit the aggregation of vacancy clusters [19].…”

Identification of Point Defects in Multielement Compounds and Alloys with Positron Annihilation Spectroscopy: Challenges and Opportunities

“…Positron annihilation experiments in hydrogen implanted equimolar FeMnNiCoCr with varying concentrations of C interstitials suggest that C effectively reduces the radiation damage by enhancing Frenkel pair recombination and suppressing vacancy clustering. [ 84 ] In contrast, removal of self‐irradiation damage (Ni ions) appears to require relatively high temperature treatments in the four‐component alloys. [ 89 ] Further work is expected to elucidate the point‐defect related phenomena in a wide variety of high‐entropy alloys.…”

“…The focus has been on the early stages of radiation damage formation, as one of the great promises of this class of materials is increased radiation tolerance compared with traditional alloys. [82][83][84][85][86] Studies on the thermal formation of vacancies in high-entropy alloys are also emerging. [87,88] Interpretation of positron annihilation results in high-entropy alloys faces similar challenges as in the nitride semiconductor alloys discussed earlier, but to a higher degree as the distribution of atoms surrounding a vacancy contains more elements.…”

Investigation of the Oxidation Behavior of Cr20Mn17Fe18Ta23W22 and Microdefects Evolution Induced by Hydrogen Ions before and after Oxidation

“…However, related research is rare to date. Lu et al [ 12 ] observed monovacancies in FeMnNiCoCr HEA using positron annihilation spectroscopy (PAS) after irradiation with low doses of hydrogen. Ramachandran et al [ 13 ] applied PAS to investigate the evolution of defects with temperature in RAFM steel irradiated by hydrogen and helium.…”