The Mo alloys reinforced by Al2O3 particles were fabricated by hydrothermal synthesis and powder metallurgy. The microstructures of Mo−Al2O3 alloys were studied by using XRD, SEM and TEM. The results show that Al2O3 particles, existing as a stable hexagonal phase (α-Al2O3), are uniformly dispersed in Mo matrix. The ultrafine α-Al2O3 particles remarkably refine grain size and increase dislocation density of Mo alloys. Moreover, a good interfacial bonding zone between α-Al2O3 and Mo grain is obtained. The crystallographic orientations of the interface of the Al2O3 particles and Mo matrix are [ 1 ¯ 11 ] α - Al 2 O 3 / / [ 1 ¯ 11 ] Mo and [ 1 1 ¯ 2 ] α - Al 2 O 3 / / [ 0 1 ¯ 1 ] Mo . Due to the effect of secondary- phase and dislocation strengthening, the yield strength of Mo−2.0vol.%Al2O3 alloy annealed at 1200 °C is approximately 56.0% higher than that of pure Mo. The results confirm that the addition of Al2O3 particles is a promising method to improve the mechanical properties of Mo alloys.
