Microstructure and compression deformation behaviors of TiAl composites reinforced by in-Situ Nano-Ti2AlC and Mn3AlC

TiAl composites reinforced by in-situ ceramic particles are attractive for high-temperature structural applications due to their low density and high specific strength. However, insufficient room-temperature strength and pronounced strain-rate sensitivity severely limit practical use. In this work, TiAl composites reinforced with in-situ Ti 2 AlC and Mn 3 AlC nano-ceramic particles were fabricated via fast hot-pressing sintering (FHPS), and their strain-rate dependent compressive and flexural behaviors were investigated. The results demonstrate that the phase constitution strongly depends on the sintering temperature. At relatively low sintering temperatures, incomplete reactions occur and residual Ti and Al phases are detected. When the sintering temperature reaches 1400°C, a purified phase constitution consisting of γ-TiAl and α 2 -Ti 3 Al lamellae accompanied by uniformly distributed in-situ formed Ti 2 AlC and Mn 3 AlC ceramic particles is obtained. Nano-sized Ti 2 AlC particles are mainly distributed along lamellar colony boundaries, while finer Mn 3 AlC particles are embedded within the TiAl lamellae, forming a heterogeneous reinforced microstructure that effectively stabilizes the lamellar architecture during deformation. Room-temperature compression tests reveal pronounced strain-rate sensitivity, characterized by simultaneous enhancements in yield strength, compressive strength, fracture strain, and work-hardening capacity at higher strain rates, whereas three-point bending tests further confirm the improved resistance to fracture under dynamic loading conditions. The superior mechanical performance is attributed to the synergistic effects of lamellar refinement, nano-ceramic reinforcement, and stable semi-coherent particle-matrix interfaces. This work provides insight into tailoring the microstructure and dynamic mechanical performance of TiAl composites through in-situ nano-ceramic reinforcement.