Effect of the reinforced phase geometry on the microstructure evolution of ceramic iron matrix composites fabricated through laser cladding.

This paper introduced spherical and non-spherical TiC ceramic particles into 4Cr5MoSiV1 steel through laser cladding technology, employing various TiC volume fractions to produce ceramic matrix composites. Scanning electron microscopy (SEM) and electron backscatter diffraction (EBSD) were used to examine TiC-reinforced composites' microstructure. The results reveal that the two ceramic matrix composites with different TiC geometries have the same phases: martensite and TiC. Because of the superior fluidity of the spherical TiC particles in the molten pool, which is distributed more evenly in the composite layer than the non-spherical TiC particles. Additionally, spherical TiC exhibits a lower dissolution rate in the laser-molten pool and has a noticeable grain refinement for the microstructure of 4Cr5MoSiV1 steel, attributed to the increase in the proportion of high-angle grain boundaries. Therefore, under the action of grain refinement, the hardness of the composite material increases. • The microstructure of the composite coatings reinforced with TiC particles of different geometry were studied in detail. • The spherical TiC-reinforced composite layer displays a more even surface and sufficient compactness and ductility. • Spherical TiC particles have a more significant grain refinement effect on the matrix, contributing the higher strength and hardness of composites. [ABSTRACT FROM AUTHOR]