Microstructural Evolution and Mechanical Properties of New and Spent W5Re/TZM Rotating Anode Targets: A Comparative Study

Abstract

Abstract

A comparative analysis of the microstructural evolution and mechanical properties between new and spent W5Re/TZM rotating anode targets is presented here. After electron bombardment, the focal spot track of the spent target exhibits network‐like cracks, grain spallation, and crack propagation along the longitudinal direction, with the surface roughness increasing from ~0.7 μm to over 10 μm. The new target exhibits parallel strip‐shaped grooves and extended microcracks along the track edges. Despite the surface degradation, the W5Re/TZM bonding interface remains intact in both targets, with no observable pores or cracks, and the grains show a random orientation without obvious texture. The densities and Vickers hardness of the W5Re and TZM alloys exhibit no significant changes after service, while the interfacial shear strength at room temperature increases from 182.4 ± 9.5 MPa to 204.2 ± 11.3 MPa. Fracture surfaces of both targets display a mixed intergranular and transgranular fracture mode. This study confirms that failure of the spent target is primarily caused by the formation of network‐like cracks, grain spallation, and crack propagation on the W5Re alloy surface in the electron bombardment region, whereas the sound condition of the interface and TZM alloy matrix offers a basis for potential repair and reuse.