A Study on Strength Characteristic Variation as amount of Plastic Deformation and Strength Anisotrophy for ECAP Al 2024 Alloy

ECAP Al 2024 합금의 소성변형량에 따른 강도 특성 및 이방성 연구

When subjected to severe shear deformation by ECAP, microstructure of Al2024 becomes nanocrystalline grained texture material. To measure the strength of that, small punch (SP) testing method was adopted as a substitute for the conventional uniaxial tensile testing because the size of material processed by ECAP were limited to $\varphi12mm$ in transverse direction. SP tests were performed with specimens in longitudinal and transverse directions of Al 2024 ECAP metal. For comparing the strength values with those assessed by SP tests, uniaxial tensile tests were also conducted with specimens in longitudinal direction. Failure surfaces of the tested SP specimens showed that failure mode was shear deformation and Al 2024 ECAP metal has an anisotropy in strength. Thus, conventional equations proposed for assessing the strength characteristics were improper to assess those of Al2024 ECAP metal. In this paper a way of assessing the strength of Al 2024 ECAP metal was proposed and was proven to be effective.