TiC-FeCr local composite reinforcements obtained in situ in steel casting

A method of the in situ fabrication of TiC-FeCr local composite reinforcements (LCR) in a cast steel matrix was discussed. The synthesis of a reinforcing phase was performed by placing the substrates of the reaction of TiC formation in the form of compressed packets in a mold cavity. In order to restrict the fragmentation of the composite zones resulting from the reactive infiltration phenomenon, the addition of 30, 50, 70, and 90 wt.% of a moderator was introduced into the initial powder mixture. The moderator was a powder mixture showing the composition of high-chromium cast iron. The presented macrostructure of a composite casting made it possible to determine the influence of the moderator addition on the stabilization of LCR. The dimensional stability and homogeneity of the LCR increased with increasing percentages of the moderator added to the initial powder mixture. The samples taken from the LCR region were analyzed, considering their structure, microstructure, mechanical properties, and wear resistance. The investigations carried out with the application of phase analysis and scanning electron microscopy (SEM) confirmed the occurrence of TiC-type phases in the structure of the composite zones. With increasing percentages of the moderator addition, a higher fraction of Cr7C3-type chromium carbides was observed in the LCR structure. The hardness of the composite zones ranged at average levels from 776 to 878 HV1 depending on the percentage of the moderator addition and pure substrates of the TiC formation.