Enhancing the reliability of Zr-3/SiC heterostructures via laser surface modification: Interfacial reaction control, residual stress relief and mechanical interlocking

To enhance the reliability of Zr-3/SiC heterostructures, this study introduces an interface engineering approach that integrates nanosecond laser surface modification with brazing. The SiC surfaces were subjected to laser modification at varying scanning pitches prior to being brazed to Zr-3 alloy at 970 ℃ using a Ti-28Ni filler. The findings indicate that laser modification fosters the development of a stable SiO 2 layer on the SiC surface, leading to the creation of regularly patterned groove structures. In the modified Zr-3/SiC joint, the interfacial products remain unchanged, but there is a notable increase in the (Ti, Zr) 5 Si 3 and ZrC phases and a reduction in the (Ti, Zr) 2 Ni phase. Furthermore, a robust SiC/TiO 2 /ZrC interface is established post-modification, reducing the residual stress at this interface by 381.9 MPa compared to the original SiC/(Ti, Zr) 5 Si 3 /ZrC interface. Additionally, the surface groove structures augment interfacial toughness through mechanical interlocking and crack deflection. At a scanning pitch of 90 μm, the shear strength peaks of modified Zr-3/SiC joint at 83.1 MPa, significantly surpassing that of the original Zr-3/SiC joint (25.3 MPa). This research elucidates the synergistic strengthening mechanisms of laser-induced surface modification in modulating interfacial reactions, alleviating residual stress, and bolstering mechanical interlocking, offering a novel strategy for the reliable joining of Zr-3/SiC nuclear fuel cladding.