Microstructure Controlled Forming of High Performance Light Metals by Combined Loading under compression and Torsion

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The compressive -torsion forming, which had be developed by the head investigator, is enable to introduce large plastic strain into a metal without changing its shape. The advantage of the forming was applied to control microstructures of some light metals, and mechanical alloying synthesis of an intermetallic compound and grain refinement of a pure aluminum. The results were as follows ;<< Synthesis of an intermetallic compound >>1. A mechanical alloying effect was found in the forming powder mixture of pure aluminum and titanium, and an intermetallic compound Al_3Ti could be synthesized by the forming process.2. Although the synthesis of the Al_3Ti was observed only in loading side of a specimen, the synthesized region can spread by changing in forming temperature, pressure and cycle.3. The synthesized intermetallic compound can be joined simultaneously with metals.<< Grain refinement of a pure aluminum >>1. Grains of 100 μm in the pure aluminum ingot can be refined under 10 μm by the compressive -torsion forming.2. Although the grain refinement was limited only in loading side of a specimen, the refined region can spread by controlling some loading conditions.3. Low temperature and low specimen height are effective to the refinement.