Dislocation-enhanced mechanical strength in T800 alloys fabricated via coaxial induction-assisted laser cladding

Due to its exceptional high-temperature wear and corrosion resistance, the T800 alloy has been widely utilized in the aerospace, steel, and petrochemical industries. However, the technology and the underlying strengthening mechanisms of the mechanical properties of T800 alloy fabricated through laser deposition remain elusive. In this research, we have harnessed an innovative coaxial induction-assisted laser material deposition (CI-LMD) technique to fabricate T800 components that are not only free from cracks but also exhibit enhanced mechanical properties. This marks the first application of CI-LMD technology in producing such high-quality T800 parts. The findings reveal that the role of induction current (IC) in the molten pool area not only preheats the matrix, thereby reducing the likelihood of cracking in the T800 alloy, but also aids in the stirring of the molten pool and the refinement of the grain structure within the T800 alloy. Concurrently, the incorporation of Fe and Cr atoms elevates the free energy level of the γ-Co solid solution, making it more susceptible to dislocation movement compared to the Cr 6 Fe 18 Mo 5 phase during the formation process of the T800 alloy. Ultimately, the CI-LMD-processed T800 alloy demonstrates a higher density of dislocation defects, finer grains, and an increased number of grain boundaries, leading to enhanced mechanical properties—such as hardness, abrasion resistance, and tensile strength—when compared to the Cast-T800 alloy.