圧縮ねじり加工法による微細化組織の分布に
及ぼすねじり負荷条件の影響

抄録

Compressive torsion processing (CTP) is a unique severe deformation process in which a work piece is simultaneously subjected to compressive and torsional loadings without a change in its cylindrical shape. Two types of torsional loading were investigated: cyclic reverse loading with various torsional angles and monotonic rotational loading with various rotations. The effects of the different torsional loading methods and torsional angle or rotational repetition on the refined microstructure distributions of pure aluminum were investigated. As a result, refined microstructures with a grain size less than 10 μm were easily formed near both basal planes of the cylindrical specimen; however, the refinement was not easy at middle regions between the basal planes. In the cyclic reverse loading, increasing torsional angle increased the size of the refined microstructure region, but it was impossible to form refined microstructures near the center axial and middle regions. On the other hand, in the monotonic rotational loading, a homogeneous refined microstructure was obtained, even with a small rotation repetition. This indicates that monotonic rotation loading is much more effective for obtaining a homogenous refined microstructure.