Development of Nb/Nb-silicide in-situ composites

Nb/Nb5Si3 in-situ composites have potential to replace nickel-based superalloys in the hottest sections of future aircraft engines. In the present study, the reactive hot press sintering, reactive spark plasma sintering and arc melting technologies are employed to produce Nb/Mb5Si3 in-situ composites with and without alloying addition. The microstructural features and mechanical properties of those composites are evaluated by SEM, EPMA, XRD, and compression test. The sintered materials show equiaxed microstructure and exhibit a large ductility at room temperature. The melted materials alloyed with Mo and/or W show co-continuous network structure of NbSS and Nb5Si3. These composites offer excellent high-temperature strength and improved room-temperature ductility. The compressive yield strength is as high as 500MPa at 1600°C for Nb-16Si-10Mo-15W alloy.