Preparation of fine-grained MoAlB with preferable mechanical properties and oxidation resistance

Abstract MoAlB has promising aeronautic and high-temperature applications due to its excellent mechanical property, favorable thermal conductivity and fantastic high temperature oxidation resistance etc. In this work, in order to obtain MoAlB with preferable properties, the fine-grained MoAlB ceramics were prepared by proprietary mechanical alloying and hot-pressing sintering technology. The microstructure observation showed that MoAlB with a small grain size of 1.26 μm could be obtained when the molar ratio of Mo, Al and B was 1:1.3:1 and the sintering temperature was 1300 °C. The testing results indicated that the as-prepared MoAlB ceramic showed better comprehensive mechanical properties compared with the reported results. The compressive strength, hardness, flexural strength and fracture toughness are 2420 MPa, 15.46 GPa, 382.87 MPa and 7.1 MPa·m1/2, respectively. It also exhibited favorable high temperature oxidation resistance due to the rapid formation of alumina scales. These results can cast light for future development of ultrahigh-temperature ceramics.