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

Two aspects of nontraditional mechanical alloying are considered as on e of the most promising solid-state materials processing: direct net-s haping into bulk materials from element constituent powders through th e combined secondary processing to MA, and, precise description and un derstanding of mechanically mixing and refinement processes. Through t he experimental studies on our developed mechanical alloying in some s ystems of materials, two key issues are found to promote the above two directions into further advancement. Those are the preclustering or p remixing effect induced by MA on the secondary processing and the effe ct 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 precur sor. On the latter, elasto-plastic super-large deformation analysis is applied to the powder compaction and extrusion process in the repeate d loading for nontraditional mechanical alloying to show that the refi nement process in MA should be attributed to the large configuration c hange of powders including their plastic failure into fragments.