Preparation, microstructure and properties of molybdenum alloys reinforced by in-situ Al2O3 particles

The conventional molybdenum alloys, lacking of hard particles enhancing wear property, have relative poor wear resistance though they are widely used in wear parts. To resolve the above question, Mo alloys reinforced by in-situ Al2O3 particles are developed using powder metallurgy method. The in-situ α-Al2O3 particles in molybdenum matrix are obtained by the decomposition of aluminum nitrate after liquid–solid incorporation of MoO2 and Al(NO3)3 aqueous solution. The α-Al2O3 particles well bonded with molybdenum distribute evenly in matrix of Mo alloys, which refine grains of alloys and increase hardness of alloys. The absolute density of alloy increases firstly and then decreases with the increase of Al2O3 content, while the relative density rises continuously. The friction coefficient of alloy, fluctuating around 0.5, is slightly influenced by Al2O3. However, the wear resistance of alloy obviously affected by the Al2O3 particles rises remarkably with the increasing of Al2O3 content. The Al2O3 particles can efficiently resist micro-cutting to protect molybdenum matrix, and therefore enhances the wear resistance of Mo alloy.

► Mo alloys reinforced by in-situ Al2O3 particles are developed using powder metallurgy method. ► The in-situ Al2O3 particles are obtained by the decomposition of Al(NO3)3, which are well bonded with molybdenum matrix. ► The Al2O3 particles refine grains of Mo alloys and increase hardness of Mo alloys obviously. ► Al2O3 particles can efficiently resist micro-cutting to protect molybdenum matrix, enhancing wear resistance of alloys.