Promising candidate for high temperature structural applications, due to its high melting point, low density and excellent oxidation resistance at high temperature. However the use of single-phase NiAl as a structural material is limited because of its lack of ductility at room temperature and low creep resistance at high temperature. Fortunately, previous investigations exhibit that the NiAl based materials possess good tribological resistance, especially at high temperature, which makes it promising to use as wear parts. Moreover, recent research [8] also reveals that high strength and good compressive ductility are beneficial to the tribological properties of NiAl. Therefore, it is necessary to improve its high temperature strength and room temperature compressive ductility in order to promote the application of NiAl-based alloy
In recent decades, great efforts have been done to enhance the mechanical properties of NiAl by solid solution strengthening, precipitation strengthening, dispersion strengthening and secondphase reinforcement. Among these methods, self-propagating high temperature synthesis (SHS) is considered as an economic technique to prepared net-shape products. Till now, many kinds of NiAl-based composites with boride, nitride, carbide or oxide inside have been fabricated. For instance, NiAl–TiB2 [15], NiAl–Al2O3 and NiAl–AlN composites have been extensively investigated to incorporate the high strength and stiffness of these ceramics into the NiAl matrix. However, to prepare the densified composite by the common reaction synthesis method is still difficult. The porosity formed during synthesis can destroy the mechanical properties of the composite. Though the subsequent hot isostatic pressing can partly solve the problem, but it results in the microstructure coarseness, which is detrimental to the room temperature mechanical properties. Therefore in the recent studies, the hot-press-aided exothermic synthesis (HPES) technique has been developed to fabricate NiAl–TiC intermetallic composites, which can well decrease the porosity. However, the high temperature, long heating time and high pressure limit its application. Morsi et al. develops hot extrusion reaction synthesis (HERS) technique to prepare Ni3Al intermetallic compound, which can well decrease the porosity and save the energy. Recently, authors’studies on the self-propagation high temperature synthesis aided with hot extrusion (SHS/HE) technique finds that the subsequent extrusion procedure can densify the synthesized material without microstructure coarsening. Therefore, in the present paper, the NiAl–TiC composite with dispersed Al2O3 oxides is prepared by SHS/HE technique. Microstructure and mechanical properties of the NiAl–TiC–Al2O3 in situ composite have been investigated.
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