Eurofer97 steel is a primary structural material for applications in fusion reactors.Laser welding is a promising technique to join Eurofer97 plasma-facing components and overcome remote handling and maintenance challenges.The interaction of the induced residual stress and the heterogeneous microstruc-ture degrades the mechanical performance of such fusion components.The present study investigates the distribution of residual stress in as-welded and post-heat treated Eurofer97 joints.The mechanis-tic connections between microstructure,material properties,and residual stress are also studied.Neu-tron diffraction is used to study the through-thickness residual stress distribution in three directions,and neutron Bragg edge imaging(NBEI)is applied to study the residual strain in high spatial resolution.The microstructures and micro-hardness are characterised by electron backscatter diffraction and nanoin-dentation,respectively.The M-shaped residual stress distribution through the thickness of the as-welded weldment is observed by neutron diffraction line scans over a region of 1.41×10 mm2.These profiles are cross-validated over a larger area(-56×40 mm2)with the higher spatial resolution by NBEI.The micro-hardness value in the fusion zone of the as-welded sample almost doubles from 2.75±0.09 GPa to 5.06±0.29 GPa due to a combination of residual stress and cooling-induced martensite.Conventional post weld heat treatment(PWHT)is shown to release～90％of the residual stress but not fully restore the microstructure.By comparing its hardness with that of stress-free samples,it is found that the mi-crostructure is the primary contribution to the hardening.This study provides insight into the prediction of structural integrity for critical structural components of fusion reactors.

Bin Zhu;Nathanael Leung;Winfried Kockelmann;Saurabh Kabra;Andrew J.London;Michael Gorley;Mark J.Whiting;Yiqiang Wang;Tan Sui

School of Mechanical Engineering Sciences,University of Surrey,Guildford,Surrey GU2 7XH,United Kingdom;Science and Technology Facilities Council(STFC)Rutherford Appleton Laboratory,ISIS Facility,Harwell OX11 0QX,United Kingdom;United Kingdom Atomic Energy Authority,Culham Centre for Fusion Energy,Culham Science Centre,Abingdon,Oxon OX14 3DB,United Kingdom

材料科学技术（英文版）

[1]Bin Zhu;Nathanael Leung;Winfried Kockelmann;Saurabh Kabra;Andrew J.London;Michael Gorley;Mark J.Whiting;Yiqiang Wang;Tan Sui-.Revealing the residual stress distribution in laser welded Eurofer97 steel by neutron diffraction and Bragg edge imaging)[J].材料科学技术（英文版）,2022(19):249-260

Eurofer97,mechanis,NBEI,nanoin,dentation,weldment,crostructure

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