Synthesis and characterization of molybdenum aluminide nanoparticles reinforced aluminium matrix composites

Aluminium matrix composites reinforced with molybdenum aluminide nanoparticles were synthesized by ball milling and reactive sintering of the mixture of aluminium and 10 wt% hydrated molybdenum oxide powders. Sintering the as milled powder in air below 750 °C produced MoAl12 intermetallic compound nanoparticles, at 750 °C produced a mixture of MoAl5 and MoAl4 nanoparticles and at 800 °C under Argon atmosphere produced predominantly MoAl4 intermetallic nano-particles in the Al matrix. The powder compacts sintered in air below 750 °C produced MoAl12 whereas at 750 °C or above formed the Al matrix composite reinforced with the MoAl5 nanoparticles. These nanoparticles become agglomerated to take up some irregular shaped flakes in the metal matrix. The reaction between Al and hydrated Mo oxide powders was found to be a favorable way to produce predominantly a particular Mo–Al intermetallic compound at a particular temperature. The Al2O3 particles formed as another reaction product, in all the above reactions, remain distributed in these composites. The composites thus formed were characterized by SEM-EDS, DTA, XRD and TEM analysis.