MA-Based Processing of Nano-structured intermaterials

首次对大块机械合金化(BMA)多次MA锻造过程中的混合和均匀化、精炼和合金化过程进行了实验研究，确定了标准工艺条件。在这些基础研究中，描述了这种BMA的相关工艺参数的可控性，以实现生产性机械合金化。采用不同的二元体系，如：铜-银、铜-钴、银-钴、镍-铝、钛-铝等，讨论了元素在合金化过程中对固溶度的内在影响。特别是对Co-Cu体系中的BMA进行了精确的研究，实现了Co团簇在铜中的纳米粒子，从而提高了材料的巨磁电阻。此外，还利用PbAl和BiAl体系不仅证明了传统球磨型MA无法机械合金化的韧性材料应转变为Al纳米颗粒材料为Pb基或Bi基材料，而且还实验地描述了韧性-韧性体系的细化过程。作为该方法在生产资料加工中的直接应用，采用了Bi-Sb-Te系统，实验证明，用该方法可以在几小时内合成Bi2Te3和Sb2Te3化合物的固溶体，并通过温压获得热电材料。值得注意的是，本方法可以获得与先进的粉末冶金方法(PIES)几乎相同的热电性能。最后，作者提出了MA可以在不同于热致SHS的过程中机械地点燃SHS。不同的过渡金属硅体系被采用，MA诱导的SHS更有利于高生成自由能体系。

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.