Microstructure and compression properties of fine Al2O3 particles dispersion strengthened molybdenum alloy

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 (alpha-Al2O3), are uniformly dispersed in Mo matrix. The ultrafine alpha-Al2O3 particles remarkably refine grain size and increase dislocation density of Mo alloys. Moreover, a good interfacial bonding zone between alpha-Al2O3 and Mo grain is obtained. The crystallographic orientations of the interface of the Al2O3 particles and Mo matrix are [(1) over bar 11](alpha-Al)(2O3)//[(1) over bar 11](Mo) and (1 (1) over bar2)(alpha-A)(lO)(3)//(0 (1) over bar1)(Mo). Due to the effect of secondary-phase and dislocation strengthening, the yield strength of Mo-2.Ovol.%Al2O3 alloy annealed at 1200 degrees 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.