Development of Plasma Synthesis to Produce Pre-Alloyed, Ultrafine Intermetallic Aluminide Powers for Injection Molding.

摘要

Intermetallics offer significant potential in a variety of military applications. Current processing does not produce significantly small particle sizes to permit the injection molding of complex geometry components. In this Phase I program, the processes of gas phase plasma reaction and plasma initiated SHS reactions (PSHS) were investigated to produce small intermetallic particles suitable for injection molding. The gas plasma reaction process failed to produce intermetallic powders with a precise stoichiometric control. By contrast, the PSHS process was successful in producing fine, irregular shaped powders of NiAl with excellent control of composition. Both stoichiometry control and capability of alloying with ternary additions was demonstrated for the PSHS process and molded powders were sintered to greater than 96% density in preliminary tests. The PSHS process can be projected to produce particles at attractive economics of $10-50/lb. A novel process termed Cathode Arc Transport (CAT) was demonstrated to produce ultra-fine (300-500nm) spherical intermetallic powders. Excellent compositional control was demonstrated in the CAT transfer process to produce alloy powder. Nanometer intermetallic particles offer significant promise to microstructural control to achieve unusual and enhanced mechanical properties.