Mingyang Jiao, Xuejian Yang, Hui Zhao, Zhijia Liu, Yan Peng, Xianhua Chen, Fusheng Pan, Baodong Shi
{"title":"Abnormal recoverable plastic strain evolution of extruded AZ31 alloy under multiple-degree-of-freedom tension after reciprocating torsion","authors":"Mingyang Jiao, Xuejian Yang, Hui Zhao, Zhijia Liu, Yan Peng, Xianhua Chen, Fusheng Pan, Baodong Shi","doi":"10.1016/j.jmst.2024.12.091","DOIUrl":null,"url":null,"abstract":"The evolution mechanism of the second-order mechanical behaviors under the complex pre-torsion path has not been clarified, which limits its potential application for optimizing precision forming processes of Mg alloy structural components. In this work, the combined loading of reciprocating free-end torsion (FET) and free-rotational tension (FRT) was performed on the extruded AZ31 solid rod with basal fiber texture. The corresponding mechanical response, microstructure evolution, and twinning behaviors were investigated, and the physical mechanism of the second-order behaviors (both the Swift and inverse Swift effects) was discussed. The results indicate that the two-stage deformation of reciprocating torsion is capable of activating tensile twins, effectively refining the surface grains, and thus improving the yield asymmetry. Due to the reverse load, detwinning dominates the deformation of reverse FET (RFET), while detwinning in FRT deformation is caused by the spontaneous rotation of the inverse Swift effect. The twin variants with <em>c</em>-axis tending to extrusion direction (ED) are predisposed to detwinning, and the bimodal texture introduced by FET is degraded. The plastic deformation of RFET is primarily coordinated by basal and prismatic slips. The large strain FRT is dominated by basal slip due to its low <span><span style=\"\"><math><mrow is=\"true\"><mi is=\"true\">S</mi><mi is=\"true\">F</mi><mo is=\"true\">(</mo><mo is=\"true\">−</mo><mo is=\"true\">−</mo><mo is=\"true\">−</mo><mo is=\"true\">)</mo></mrow></math></span><span style=\"font-size: 90%; display: inline-block;\" tabindex=\"0\"><svg focusable=\"false\" height=\"2.779ex\" role=\"img\" style=\"vertical-align: -0.812ex;\" viewbox=\"0 -846.5 4953.9 1196.3\" width=\"11.506ex\" xmlns:xlink=\"http://www.w3.org/1999/xlink\"><g fill=\"currentColor\" stroke=\"currentColor\" stroke-width=\"0\" transform=\"matrix(1 0 0 -1 0 0)\"><g is=\"true\"><g is=\"true\"><use xlink:href=\"#MJMATHI-53\"></use></g><g is=\"true\" transform=\"translate(645,0)\"><use xlink:href=\"#MJMATHI-46\"></use></g><g is=\"true\" transform=\"translate(1395,0)\"><use xlink:href=\"#MJMAIN-28\"></use></g><g is=\"true\" transform=\"translate(1784,0)\"><use xlink:href=\"#MJMAIN-2212\"></use></g><g is=\"true\" transform=\"translate(2785,0)\"><use xlink:href=\"#MJMAIN-2212\"></use></g><g is=\"true\" transform=\"translate(3785,0)\"><use xlink:href=\"#MJMAIN-2212\"></use></g><g is=\"true\" transform=\"translate(4564,0)\"><use xlink:href=\"#MJMAIN-29\"></use></g></g></g></svg></span><script type=\"math/mml\"><math><mrow is=\"true\"><mi is=\"true\">S</mi><mi is=\"true\">F</mi><mo is=\"true\">(</mo><mo is=\"true\">−</mo><mo is=\"true\">−</mo><mo is=\"true\">−</mo><mo is=\"true\">)</mo></mrow></math></script></span>/CRSS. The interaction between twinning and detwinning dominates the multi-directionality of the Swift effect during reciprocating torsion, and the cumulative effect of strain hardening further enhances the dependence of RFET axial strain on basal slip. The d<em>γ</em>/d<em>ε</em> index successfully captures the evolution of the inverse Swift effect during FRT. The forward rotation of the solid rod is caused by the inversion of the radial residual shear stress field, and the internal stress introduced by the torsional inhomogeneity is compensated. The subsequent reverse rotation is the result of balancing the orientation inhomogeneity and local strain heterogeneity introduced by the shear deformation. The increase in the reverse rotation rate is caused by detwinning.","PeriodicalId":16154,"journal":{"name":"Journal of Materials Science & Technology","volume":"92 1","pages":""},"PeriodicalIF":11.2000,"publicationDate":"2025-03-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Journal of Materials Science & Technology","FirstCategoryId":"88","ListUrlMain":"https://doi.org/10.1016/j.jmst.2024.12.091","RegionNum":1,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q1","JCRName":"MATERIALS SCIENCE, MULTIDISCIPLINARY","Score":null,"Total":0}
引用次数: 0
Abstract
The evolution mechanism of the second-order mechanical behaviors under the complex pre-torsion path has not been clarified, which limits its potential application for optimizing precision forming processes of Mg alloy structural components. In this work, the combined loading of reciprocating free-end torsion (FET) and free-rotational tension (FRT) was performed on the extruded AZ31 solid rod with basal fiber texture. The corresponding mechanical response, microstructure evolution, and twinning behaviors were investigated, and the physical mechanism of the second-order behaviors (both the Swift and inverse Swift effects) was discussed. The results indicate that the two-stage deformation of reciprocating torsion is capable of activating tensile twins, effectively refining the surface grains, and thus improving the yield asymmetry. Due to the reverse load, detwinning dominates the deformation of reverse FET (RFET), while detwinning in FRT deformation is caused by the spontaneous rotation of the inverse Swift effect. The twin variants with c-axis tending to extrusion direction (ED) are predisposed to detwinning, and the bimodal texture introduced by FET is degraded. The plastic deformation of RFET is primarily coordinated by basal and prismatic slips. The large strain FRT is dominated by basal slip due to its low /CRSS. The interaction between twinning and detwinning dominates the multi-directionality of the Swift effect during reciprocating torsion, and the cumulative effect of strain hardening further enhances the dependence of RFET axial strain on basal slip. The dγ/dε index successfully captures the evolution of the inverse Swift effect during FRT. The forward rotation of the solid rod is caused by the inversion of the radial residual shear stress field, and the internal stress introduced by the torsional inhomogeneity is compensated. The subsequent reverse rotation is the result of balancing the orientation inhomogeneity and local strain heterogeneity introduced by the shear deformation. The increase in the reverse rotation rate is caused by detwinning.
期刊介绍:
Journal of Materials Science & Technology strives to promote global collaboration in the field of materials science and technology. It primarily publishes original research papers, invited review articles, letters, research notes, and summaries of scientific achievements. The journal covers a wide range of materials science and technology topics, including metallic materials, inorganic nonmetallic materials, and composite materials.