Diffusion bonding W and RAFM-steel with an Fe interlayer by hot isostatic pressing

Abstract W and RAFM-steel joint is the major feature of the plasma facing component in the first wall of a fusion reactor. In present work, W and RAFM-steel were successfully diffusion bonded with an Fe interlayer by hot isostatic pressing at 980 °C and 150 MPa for 1 h. Two Fe-rich phases, a Fe2W type phase and a Fe3W3C type phase, were formed at the W/Fe interface. Both phases were drastically deformed under the interfacial thermal stress, leading to stress-induced martensitic transition of the Fe2W type phase and plastic slip of the Fe3W3C type phase. Their deformation could reduce the residual stress significantly at the W/reaction layer interface and the W/Fe/RAFM-steel joint exhibited high bonding strength (>240 MPa) and ductility in the shear test.