Microstructure and mechanical properties of additive manufactured TiC-reinforced Fe55Cr25Co10Ni10 high-entropy alloy composites

Abstract

The FeCrCoNi series of high-entropy alloys have received widespread attention due to their excellent properties at room and low temperatures, however, the relatively low yield strengths severely limit their wide application. Currently, the research efforts in the field of ceramic particles strengthening mainly focus on the equiatomic high-entropy alloy systems. However, there have been few studies on high-entropy alloys with non-equiatomic ratios. This paper provides a detailed investigation into the mechanism of the effect of 5 wt% TiC ceramic particles on the microstructure, mechanical properties and friction and wear properties of Fe55Cr25Co10Ni10 high-entropy alloys. The results indicated that the alloy’s phase structure of the alloy changes significantly after addition 5 wt% TiC ceramic particles. The alloy transitions from the original single FCC solid solution to a composite structure consisting of FCC solid solution and TiC particles. At the same time, the alloy’s microstructure is transformed from a single columnar crystal structure to a composite structure, which includes columnar dendrites, cellular dendrites and unmelted TiC particles. Notably, this transformation has significantly improved mechanical properties: the yield strength increased from 203 MPa to 254 MPa (improved 25.1 percent), and the tensile strength increased from 542 MPa to 635 MPa (improved 17.2 percent). Theoretical calculations and practical test analyses reveal that addition TiC ceramic particles leads to a significant increase in yield strength, which is mainly attributed to the combined contribution of the Hall-Petch strengthening effect, the dislocation strengthening mechanism and the Orowan strengthening effect. In addition, it is demonstrated that high-entropy alloy composites’ friction and wear performance at room temperature exhibits excellent characteristics compared to high-entropy alloy materials. It is expected to be widely applied in the manufacturing of components in key areas of the aerospace field.