NONTRADITIONAL MECHANICAL ALLOYING BY THE CONTROLLED PLASTIC-DEFORMATION, FLOW AND FRACTURE PROCESSES

Two aspects of nontraditional mechanical alloying are considered as one of the most promising solid-state materials processing: direct net-shaping into bulk materials from element constituent powders through the combined secondary processing to MA, and, precise description and understanding of mechanically mixing and refinement processes. Through the experimental studies on our developed mechanical alloying in some systems of materials, two key issues are found to promote the above two directions into further advancement. Those are the preclustering or premixing effect induced by MA on the secondary processing and the effect of controlled plastic flow and failure on the mechanical alloying. With respect to the former issue, MA combined with the shock reactive synthesis is developed to demonstrate that the intermetallic compound should be synthesized in the solid-state reaction from the MAed precursor. On the latter, elasto-plastic super-large deformation analysis is applied to the powder compaction and extrusion process in the repeated loading for nontraditional mechanical alloying to show that the refinement process in MA should be attributed to the large configuration change of powders including their plastic failure into fragments.