Study on the microstructure and properties of iron-based composites locally reinforced by in-situ submicron TiC particles

Abstract

This study discussed the strengthening mechanism of in-situ submicron TiC particles on high chromium cast iron matrix composites. By changing the Ti content, the microstructure evolution and performance change law of the composites are analyzed. The results show that the average particle size of the TiC particles will grow with the increase of the Ti content in the preforms. After the in-situ reaction, there will be a transition layer of 20–30 μm in the interfacial zone of the composite, and a high density of dislocations will appear at the same time. Furthermore, the presence of submicron TiC particles in the microstructure can significantly improve the strength and wear resistance of the composites. By contrast, only the Ti content in preforms is 50%, the microstructure and performance of the test steel (S2 steel) are the most ideal. The TiC particles in the composite area account for more than 70%, and the hardness is as high as 1236 HV, which is more than twice the hardness of the matrix. Under the same wear conditions, the mass loss and wear rate of S2 steel are the smallest, which are only 0.2 ± 0.1 mg and 3.08 × 10−6 ± 0.05 mm3/Nm, respectively.