Effect of mechanical alloying on combustion synthesis of MoSi2

Characteristics of the combustion synthesis of MoSi2 using elemental Mo and Si powder mixtures prepared by mechanical alloying were investigated. The mechanical alloying resulted in powders of pseudolamellar structure and a p artial conversion of the elemental powders to hexagonal MoSi2 phase. Combus tion reaction of the mixture was ignited around 670 degreesC, which is much lower than that with the powder prepared by low-energy ball milling. A mat hematical model was developed to demonstrate the possibility of the ignitio n of the combustion reaction of the lamellar structure via a solid-state di ffusional process. On the basis of model, effects of mechanical alloying ti me on the ignition temperature and combustion temperature are discussed.