MA-Based Processing of Nano-structured intermaterials

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Mixing and homogenization, refining and alloying processes in the bulk mechanical alloying (BMA) by the repeated MA-forging were first experimentally investigated to define the standard process condition. In these fundamental studies, controllability of the related process parameters to this BMA was described towards productive mechanical alloying. Various binary systems such as Cu-Ag, Cu-Co, Ag-Co, Ni-Al, Ti-Al and so forth were employed to discuss the intrinsic effect of constituent elements on the solid solubility in the alloying processes. In paticular, BMA in the Co-Cu system was precisely studied to realize nano-particulation of Co clusters into Cu matrix for improvement of giant magneto-resistance by the present method. In addition, Pb-Al and Bi-Al systems were also employed not only to demonstrate so ductile materials as can never be mechanically alloyed by the conventional milling-type MA should be converted into Al nano-particulate materials into Pb or Bi matrices but also to experimentally describe the refining process in the ductile-ductile system. As the direct application of the present approach to productive materials processing, Bi-Sb-Te system was employed to experimentally demonstrate that the solid solution of Bi_2Te_3 and Sb_2Te_3 compounds can be synthesized by the present method within a couple of hours and to obtain the thermoelectric materials by warm-pressing the yielded solid solution bulk compact. To be noted, nearly the same thermoelectric properties as attained by the advanced powder metallurgical method (PIES) can be obtained by the present method. Finally, Authors proposed that SHS can be ignited mechanically through MA in the different process from thermally-induced SHS.Various transition metal silicon systems were employed that MA-induced SHS is favored by the high formation free energy systems.