A thermodynamic description of the Al-Mo-Si system

The thermodynamic reassessment of the Al-Mo-Si system was performed using the CALPHAD technique. The solution phases (liquid, bcc, fcc and diamond) were modeled as a substitutional solution. The compounds AlMo3 in the Al-Mo system and Mo3Si in the Mo-Si system had the same A15 crystal structure, and were treated as one phase and described by a two-sublattice model (Al,Mo,Si)(Al,Mo)3. The compound Mo5Si3 with D8m crystal structure was treated as the formula Mo0.5(Mo,Si)0.125(Al,Mo,Si)0.375 in the Al-Mo-Si system. Other compounds, Al63Mo37, Al8Mo3, Al3Mo, Al4Mo, Al17Mo4, Al22Mo5, Al12Mo and Al5Mo in the Al-Mo system, MoSi2 in the Mo-Si system, and ternary compounds C40 and C54 were treated line compounds (Al,Si)mMon in the Al-Mo-Si system. Based on the published experimental isothermal sections and the liquidus surface projection, the Al-Mo-Si system was re-optimized, and a set of self-consistent thermodynamic parameters was obtained.