Microstructure evolution of SiCf/TiMoNb heterogeneous core reinforced Ti2AlNb-based composites

• A novel architecture of SiC f /TiMoNb heterogeneous core reinforced Ti 2 AlNb composites was designed and prepared. • Comprehensive microstructural evolution of both matrix and SiC/TiMoNb interface was systematically investigated during HIP. • Distinct interdiffusion mechanisms at TiMoNb/Ti 2 AlNb interface were elucidated with detailed phase characterization. SiC fiber-reinforced metal matrix composites (MMCs) show promise for aerospace but face temperature limits, with Ti 2 AlNb-based composites capped at 750 °C due to interfacial reactions. Refractory multi-principal element alloys (MPEAs) offer high-temperature potential. This study explores SiC f /TiMoNb-reinforced Ti 2 AlNb-based composites, focusing on microstructure and interfacial evolution during processing. It was found that the precursor wires matrix exhibited a single BCC phase with primary TiC at the C/TiMoNb interface. Following hot isostatic pressing (HIP), the composite matrix retained a BCC structure, with extensive dislocations, and TiC particles precipitates at grain boundaries. The formation of a 0.55 µm TiC reaction layer at the C/TiMoNb interface was observed and minor Ti 5 Si 3 phase formed nearby the TiC layer. The Ti 2 AlNb capsule displayed an α 2 + B2 + O lamellar structure, with excellent bonding to the TiMoNb matrix. The interdiffusion area evolved into two distinct regions: a single B2 phase, equiaxed α 2 grains with lamellar B2 + O structures. Crystallographic orientation relationships were summarized. Numerous < 111 > dislocations in the B2 phase, deformation bands in the α 2 phase, and (110) twins in the O phase were observed. This work provides critical insights into microstructural evolution during HIP, offering a foundation for understanding failure mechanisms and optimizing the mechanical performance of these advanced composites.