ABOUT THE YIELD PLATEAU UNDER SIGN-VARIABLE LOADING
نویسندگان
چکیده
During tension of samples low-carbon steels and some other plastic materials, the sharp yield point plateau are fixed on deformation diagram. In this case, Chernov-Luders bands appear surface sample in local section, which then propagate along axis. The physical nature is established: drop load after reaching (upper) limit occurs as a result dislocations being an extraction out cloud embedded atoms vacancies (Cottrell's cloud). At occurrence , strain limited to small area. When increases, plasticity zone (the marked diagram at time) expands, stress-strain state becomes almost homogeneous, if we do not consider its boundary with elastic region. end plateau, entire experiences uniform deformation, excluding ends (galtels). From on, shows material hardening; presumably, hardening occurred from very beginning, but was hidden under plateau. This evidenced by resulting strain-induced anisotropy. After unloading sample, when front (in form bands) has yet passed through Bauschinger's effect observed subsequent change stress sign. fact that localized certain volume, similar what during neck formation, spreads serves proof due immediately falls. Therefore, plastically deformable part did have growth, it would be able spread sample. paper presents experimental data sign-variable torsion thin-walled tubular steel 45 annealed state. atdiagram development distinct sections length test obtained. reconstructed using well-known Masing's principle.
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ژورنال
عنوان ژورنال: ??????? ????????? ????????????? ?????????????????? ???????????????? ????????????
سال: 2021
ISSN: ['2224-9893', '2226-1869']
DOI: https://doi.org/10.15593/perm.mech/2021.3.13