Mediation of high temperature radiation damage in bcc iron by Au or Cu precipitation

Abstract

High temperature radiation damage in binary bcc Fe alloys containing 1 atomic % Au or Cu due to Fe ion irradiation at 550°C to a peak dose of 2.8 and 8.3 dpa is studied. The precipitation behavior of gold and copper and its correlation to the irradiation-induced defects is studied by transmission electron microscopy and variable energy positron annihilation spectroscopy (VEPAS). The increase of S parameters from VEPAS indicates the formation of open volume defects upon irradiation. Disc-shaped Au precipitates, grown from the irradiation induced dislocations, are observed in the Fe-Au alloy. In the Fe-Cu alloy, spherical Cu particles are formed but no direct connection between Cu precipitates and radiation damage is detected. For the Fe-Au alloy, the surface hardness dramatically increases for a dose of 2.8 dpa, with a slight decrease as the irradiation dose is enhanced to 8.3 dpa. In the Fe-Cu alloy, radiation hardening increases continuously.

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

“…The original irradiation dislocation played an important role in site selectivity of precipitates. When the samples are exposed to high temperature for a long time, the Au-V complexes aggregate around the irradiated dislocations, which act as nucleation sites to form the Au-rich precipitates [23,44]. Therefore, Au precipitates and dislocations loops dominate the microstructure along the L 5 line [45].…”

“…Therefore, Au precipitates and dislocations loops dominate the microstructure along the L 5 line [45]. For the Fe-Au-W alloy, simultaneously the mixtureof dislocations between the Au precipitates [23,45] and the Fe matrix act as nucleation sites of the W-rich Laves precipitates, which influence the precipitation behavior of Au-rich precipitates.…”

“…Previous studies have demonstrated [22,23] that there exists an even stronger spatial correlation of Au precipitates with He and Fe ion irradiation-induced defects than in the case of irradiated Fe-Cu alloys Ab initio calculations indicated that the binding energy of Au-V n is stronger than that of Cu-V n , and that He atoms can weaken the trapping capability of vacancies. In our previous study, it was shown that radiation hardening of Fe-Au alloy barely took place when increasing the irradiation dose because of Au precipitation on irradiation-induced defects [22].…”

A Review of Self-healing Metals: Fundamentals, Design Principles and Performance

“…Inspired by the work on self-healing of creep damage in Fe-based alloys, Zhang and coworkers have evaluated the self-healing potential of solute Cu and Au in Fe for radiation damage [73][74][75]. Under irradiation (550 °C, He + ), site-specific Au precipitation at defect sites was observed (Fig.…”