Microstructure and mechanical behavior of in situ TiC reinforced Fe3Al(Fe–23Al–3Cr)matrix composites by mechanical alloying and vacuum hot-pressing sintering technology

Abstract

In this paper, Fe3Al (Fe–23Al–3Cr) alloys reinforced with in-situ TiC precipitates were fabricated using a combination of high-energy ball milling and vacuum hot-pressing sintering technology. The experiment found that the 1 × 10−3 Pa vacuum was the optimal preparation conditions of composites. The results show that in-situ TiC ceramic is an efficient method to improve the mechanical properties of Fe3Al/TiC composites. The hardness and compressive strength of the composite significant increases with in-situ TiC. And note that in-situ 50% TiC composite has the highest compressive strength (2572 MPa). By comparison, the compressive strength and hardness of all the in-situ composites (15%–50%) are not much different from that of the same contents of ex-situ TiC composites. The bending strength decrease with in-situ TiC content increase except that of in-situ 15%TiC composite, and it exhibits the highest bending strength (1941 MPa). In addition, the fracture toughness of the composites decreases significantly with increasing TiC content. The main reason is that the brittle ceramic TiC particles could act as obstacles for the ductility of Fe3Al alloys. The bending fracture mode transforms from tough fracture mode to brittle cleavage facets crack mode.