Preparation, microstructure and properties of molybdenum alloys reinforced by in-situ Al_2O_3 particles

摘要

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 Al_2O_3 particles are developed using powder metallurgy method. The in-situ a-Al_2O_3 particles in molybdenum matrix are obtained by the decomposition of aluminum nitrate after liquid-solid incorporation of MoO_2 and A1(NO_3)_3 aqueous solution. The a-Al_2O_3 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 Al_2O_3 content, while the relative density rises continuously. The friction coefficient of alloy, fluctuating around 0.5, is slightly influenced by Al_2O_3. However, the wear resistance of alloy obviously affected by the Al_2O_3 particles rises remarkably with the increasing of Al_2O_3 content. The Al_2O_3 particles can efficiently resist micro-cutting to protect molybdenum matrix, and therefore enhances the wear resistance of Mo alloy.