Metallurgical Synthesis of TiC/Al3Ti Surface Composite Coating

A TiC/Al3Ti intermetallic matrix composite coating was fabricated on an iron substrate by the casting and reaction synthesis. Phase, microstructure and interface morphology of the coating were investigated, and hardness measured as well. The formation mechanism of the coating was also discussed. The results show that the reaction of Al-Ti-C system is fully completed under the action of molten iron liquid to achieve the TiC particle reinforced intermetallic matrix composite coating. It is observed that TiC particles are uniformly mounted in Al3Ti matrix and the coating is compact. When the content of TiC is less, TiC presents a strip form; with increasing of TiC, its size is decreased and the shape changes from strip to granular. The interface between the coating and iron substrate has good metallurgical bonding with a gradient distribution of Al, Ti, Fe and C from the coating to the interface. The hardness of the coating is substantially higher than that of the iron matrix and slightly increased with increasing TIC content.