Net-shape forming of particulate materials by repeated MA-forming

As a non-traditional high-speed mechanical alloying, a repeated MA-forging has been investigated not only to fabricate non-equilibrium and nano-structured solid materials but also to make near-net shaping of particulate materials especially for binary systems. In particular, Si-Al and Bi-Al are difficult to fabricate their particulate materials by either casting or conventional powder metallurgy; since both Si and Bi have little or no solubility with aluminum, Si precipitates in the acicular shape or spherical Bi with large diameter is separated from aluminum matrix. Application of high pressure pressing and severe shear deformation in cyclic manner provides Si-Al mixture with finely fragmented Si particles distributed in Al matrix or Bi-Al solution with refined Bismuth grains in aluminum matrix. The most attractive point in production of this type of particular materials lies in a near-net shaping only by change of die-set system in the same MA-forging machine; resizing pressing by the same MA-forging machine enables us to fabricate parts of MAed particulate materials for Si-Al and Bi-Al.