Preparation and formation mechanism of TaCp/Fe cluster-reinforced iron matrix composites

Abstract

In ceramic particle reinforced iron matrix composites, a significant increase in the volume fraction of the reinforcing phase results in enhanced strength but a dramatic decrease in toughness. This study prepared TaC_p/Fe cluster-reinforced iron matrix composites through a combination of lost foam casting and in-situ reaction. During lost foam casting, tantalum wires react with gray cast iron in a solid-liquid process to form a preform. In the subsequent in-situ solid-solid reaction, carbon atoms continuously fill the lattice gaps of Ta to form TaC, which then results in the formation of a three-dimensional cluster-reinforced structure of TaC_p and α-Fe around the tantalum wires. TaC_p/Fe cluster-reinforced iron matrix composites have a spatial architecture combining soft and hard phases: The tantalum wires, ferrite, and the carbon-poor regions surrounding the reinforcement constitute the soft regions; TaC_p and its cluster reinforcement exhibits excellent load-bearing properties. The in-situ reaction samples obtained at 1115 °C for 7 h exhibited a compressive yield strength of 419 ± 9 MPa and a strain of 21.1 ± 0.6 %, which are 1.8 times and 1.3 times that of the matrix, respectively. In conclusion, the TaC_p/Fe cluster-reinforced iron matrix composites prepared by lost foam casting combined with in-situ reaction method have favorable strength-toughness matching properties.