Coarse TiC particles reinforced H13 steel matrix composites produced by laser cladding

Coarse TiC particles (more than 50 μm) reinforced H13 steel composites produced by laser cladding with various ceramic volume fraction were investigated. The effects of the ceramic volume fraction on the microstructure and hardness of the produced TiC/H13 composite were obtained. The results indicated that preheating conbined with slowing laser beam scanning speed were relatively useful for crack suppression and formation of composites with high TiC volume fraction. The microstructure of the TiC/H13 composite consisted of various TiC particles, including coarse TiC, initial fine TiC, primary TiC, lamellar-type eutectic TiC, austenite and martensite. By increasing the concentration of TiC in the composite, the volume fraction of residual austensute and the carbon content of martensite as well as the composite hardness had a significant increase. Nanoindentation hardness results showed that the hardness of the initial TiC particle was the highest, followed by the primary TiC, among the various shaped TiC within the deposit. The highest average hardness of the TiC/H13 composite was 1365 HV, which was more than twice as much as the H13 substrate hardness.