Microstructure and mechanical properties of Fe-based composite coatings reinforced with in-situ synthesized multilayer core-shell Al2O3@TiC@TiB ceramic particles via laser cladding

In this study, a laser cladding technique was employed to successfully fabricate an iron-based composite coating reinforced with α-Al2O3@TiC@TiB multi-layered core–shell ceramic particles on a Q235 substrate using a mixture of Fe60, 80TiFe, and B4C pre-alloyed powders. Through systematic microstructural and property characterizations, the unique role of α-Al2O3 particles in the composite coating was revealed. The research demonstrated that the addition of α-Al2O3 not only facilitated the in-situ synthesis of multi-layered core–shell ceramic particles but also significantly promoted the heterogeneous nucleation of TiC, resulting in a non-coherent relationship of α-Al2O3 (104)//TiC(111). Furthermore, TiC served as a heterogeneous nucleation substrate for TiB, forming a coherent relationship of TiC(111)//TiB(210). Compared to the coating without α-Al2O3 the composite coating with α-Al2O3 exhibited a 16.2% refinement in grain size and a 10.5% improvement in microhardness. Combined with thermodynamic calculations, this study elucidated, for the first time, the growth mechanism of the α-Al2O3@TiC@TiB multi-layered core–shell ceramic particles, providing a novel theoretical foundation for the design of high-performance iron-based composite coatings.

Duke Scholars

Author Zhaohui Wang Pathology