Investigation of 100-Hour Aging of Niobium Composite Reinforced with Monocrystalline Fibers of α-Al2O3

The effect of 100-hour aging at 1350°C on the matrix–fiber interfacial bond, matrix structure, bond type, and high-temperature strength of Nb composite reinforced with α-Al2O3 single crystal fibers has been studied. It has been found that, in the samples after pressing, as well as after 100-hour aging, no chemical interaction is detected at the matrix–fiber interface, i.e., there is no “chemical” bond, and a “mechanical” bond is realized in Bauman’s notation. At the same time, the process of mutual diffusion of matrix and fiber elements after 100-hour aging has been studied and an increase in the strength of the composite has been found. This indicates an increase in the frictional bond and/or formation of another type of bond, which at this stage does not cause fiber degradation. It was not possible to determine numerical values of the contribution of the “new type” of bonds to the increase in the strength of the composition.