UKAEA-CCFE-PR(21)59

A novel pathway for multi-scale high-resolution time-resolved residual stress evaluation of laser-welded Eurofer97 Pending Yiqiang Wang

The plasma-facing components of future fusion reactors, where the Eurofer97 is the primary structural material, will be assembled by laser-welding techniques. The heterogeneous residual stress induced by welding can interact with the microstructure, resulting in a degradation of mechanical properties and a reduction in joint lifetime. Here, a Xe+ plasma focused ion beam, with digital image correlation (PFIB-DIC) and nanoindentation are used to reveal the mechanistic connection between residual stress, microstructure and micro-hardness. This study is the first to use the PFIB-DIC to evaluate the time-resolved multi-scale residual stress at length-scale of tens of micrometres for laser-welded Eurofer97. A non-equilibrium micro-scale residual stress is observed, which makes a significant contribution at the macroscopy scale. The micro-hardness is similar for the fusion zone and heat affected zone (HAZ), although the HAZ exhibits around ~30% tensile residual stress softening. The results provide insight into maintaining structural integrity for this critical engineering challenge.

Collection:
Journals
Journal:
Science Advances
Publisher:
AAAS (American Association for the Advancement of Science)