A critical review on bimetallic issues in part repair using additive manufacturing

Abstract In this review, bimetallic additive manufacturing (AM) applications, issues, repair methods, and characterization techniques were explored to meet the current demand for industrial applications with customized features. Bimetallic part repair using AM has emerged as a promising solution for extending the service life of high-value engineering components, preventing new replacement, reducing material wastage, and minimizing downtime. However, when dissimilar metals are joined during repair, complex metallurgical and mechanical issues arise. This review critically examines the challenges associated with bimetallic part repair using various AM techniques, focusing on microstructural incompatibility, residual stresses, intermetallic formation, and differences in thermal and mechanical properties. The study consolidates findings from recent research on material selection strategies, process parameter optimization, and post-processing treatments to improve interfacial integrity. Furthermore, the review highlights existing gaps in understanding diffusion mechanisms, thermal mismatch, and long-term performance of bimetallic joints. Finally, future perspectives are discussed to guide the development of more reliable and efficient repair processes for dissimilar material systems in additive manufacturing.