Roll-formability of cryo-rolled ultrafine aluminium sheet

Marnette, Jascha; Weiß, Matthias; Hodgson, Peter

doi:10.1016/j.matdes.2014.06.036

Cited by 29 publications

(6 citation statements)

References 15 publications

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“…There are many applications of CR for fabrication of UFG/NG Al alloys. [59][60][61][62][63][64][65][66][67][68][69][70] Optimal CR reduction and subsequent annealing conditions result in ultrafine grains in CP Al with both high strength and high ductility. [59] Cryorolled Al sheets can reach a tensile strength that is 30% higher compared to Al sheets SR-processed at room temperature.…”

Section: Fig 5 Cryorollingmentioning

confidence: 99%

“…[59] Cryorolled Al sheets can reach a tensile strength that is 30% higher compared to Al sheets SR-processed at room temperature. [60] Under optimal processing conditions, suppression of dynamic recovery during cryogenic deformation results in high defect density, which in turn results in increased nucleation sites during annealing, and leads to finer grains. [61] The effect of annealing on the evolution of microstructure and mechanical properties of Al 5083 alloy by CR was investigated by Lee et al [62] Optimisation of CR and subsequent annealing processes resulted in a mixture of equiaxed grains of <200 nm and elongated subgrains, exhibiting a good combination of high strength and uniform elongation, as shown in Fig.…”

Section: Fig 5 Cryorollingmentioning

confidence: 99%

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Special Rolling Techniques for Improvement of Mechanical Properties of Ultrafine‐Grained Metal Sheets: a Review

Lü

Tieu

et al. 2015

Adv Eng Mater

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Interest in ultrafine-grained (UFG) materials has grown rapidly in past 20 years. This review focuses on the application of special rolling techniques for improvement of the mechanical properties of UFG metal sheets. These techniques include asymmetric rolling, cryorolling, asymmetric cryorolling, cross-accumulative roll bonding, and skin-pass rolling. The techniques also include a combination of processes such as equal channel angular press and subsequent rolling, combined high-pressure torsion and subsequent rolling, as well as combined accumulative roll bonding and subsequent asymmetric rolling. We also discuss the main mechanisms leading to improvement in the ductility of UFG materials related to the special rolling techniques. properties of ultrafine-grained (UFG) metal sheets. These techniques include asymmetric rolling, cryorolling, asymmetric cryorolling, cross-accumulative roll bonding and skin-pass rolling. The techniques also include a combination of processes such as equal channel angular press and subsequent rolling, combined high pressure torsion and subsequent rolling, as well as combined accumulative roll bonding and subsequent asymmetric rolling. We also discuss the main mechanisms leading to improvement in the ductility of UFG materials related to the special rolling techniques.

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Section: Fig 5 Cryorollingmentioning

confidence: 99%

Section: Fig 5 Cryorollingmentioning

confidence: 99%

Special Rolling Techniques for Improvement of Mechanical Properties of Ultrafine‐Grained Metal Sheets: a Review

Lü

Tieu

et al. 2015

Adv Eng Mater

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“…Enhanced formability in biaxial stretching was related to profuse micro-shear banding in biaxial stretching of the UFG processed Cu providing significant amount of plastic deformation and, therefore, formability, that does not occur during uniaxial tensile testing of the UFG pure Cu [41]. In [46], cryorolled UFG Al was successfully roll formed into simple longitudinal sections having profile radii of 15 mm despite its low uniaxial tensile elongation and limited hardening in tension. …”

Section: Strategies To Improve Ductility Of Ufg Materials Based On Mamentioning

confidence: 99%

Enhanced ductility of ultra-fine grained metallic materials

Sabirov¹

2015

LoM

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The ultra-fine grained metallic materials obtained via severe plastic deformation typically show very high mechanical strength but low tensile ductility, which dramatically limits their practical utility. Significant efforts were made to improve uni-axial tensile ductility of ultra-fine grained metallic materials. The developed approaches can be divided into two main groups: the 'mechanical' and 'microstructure-based' strategies. The 'mechanical' strategies are based on idea of manipulation with testing parameters (temperature, strain rate, stress state, etc.) to delay localization of plastic deformation at macro scale. Intelligent microstructural design to suppress necking at early stages of plastic deformation is employed in 'microstructural' strategies. This work aims to provide a short overview of these approaches with an emphasis on the effects of basic deformation mechanisms, chemical composition and microstructural features. It is demonstrated that the developed strategies are able to restore the uni-axial tensile ductility of the ultra-fine grained materials to the level of their coarse-grained counterparts and even to further improve it. Special attention is paid to formability of ultra-fine grained metallic materials during deformation under complex stress state. The ultra-fine grained metallic materials can demonstrate enhanced formability in deformation under complex stress state even if their uni-axial tensile ductility is very low. This is related to activation of deformation mechanisms promoting ductility, which are not active during uni-axial tensile testing.Keywords: ultra-fine grained metallic materials, strength, ductility, formability Повышенная пластичность ультрамелкозернистых металлических материаловУльтрамелкозернистые металлические материалы, полученные путем интенсивной пластической деформации, име-ют очень высокую механическую прочность, но низкую пластичность при растяжении, что очень сильно ограни-чивает их практическую применимость. Для повышения пластичности ультрамелкозернистых металлов при одно-осном растяжении были приложены значительные усилия. Разработанные подходы могут быть разделены на две основные группы, которые можно назвать «механическими» и «микроструктурно-основанными» стратегиями. «Ме-ханические» стратегии основаны на идее манипуляции параметрами испытаний (температурой, скоростью дефор-мации, напряженным состоянием и т.д.) для задержки локализации пластической деформации в макроскопическом масштабе. В «микроструктурных» стратегиях используется разумный микроструктурный дизайн для подавления шейкообразования в ранних стадиях пластической деформации. Цель настоящей работы -представить краткий обзор указанных подходов с упором на влияние основных деформационных механизмов, химического состава и ми-кроструктурных особенностей. Показано, что разработанные стратегии могут восстановить пластичность при од-ноосном растяжении ультрамелкозернистых материалов до уровня крупнозернистых материалов и даже улучшить ее дальше. Отдельное внимание уделено формуемости ультрамелкозерни...

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“…The process can be used to form material that combines high strength [2] with limited ductility [3,4] and is increasingly used in the automotive industry for the manufacture of structural and crash components [5]. In roll forming, the overall level of longitudinal strain is low, but common shape defects such as edge ripple [6] and oil canning [7] are believed to result from extremely small secondary plastic strains that do occur during forming.…”

Section: Introductionmentioning

confidence: 99%

Bending behaviour and oil canning in roll forming a steel channel

Weiß

Abeyrathna

Gangoda

et al. 2017

Int J Adv Manuf Technol

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In roll forming a wide flat channel, problems were experienced with wrinkling, or 'oil canning' in the web. This is a common shape problem in roll forming wide panels that have flat regions in the profile. Coils from four different suppliers were used in production; with three of these, wrinkling could be controlled, but one coil had to be discarded. Tensile tests performed on all materials did not identify major differences in the coils although one material showed a slight indication of ageing. Free bending tests were performed with a new standalone bend tester specifically developed for material characterisation on the shop floor. The bending tests performed on strips cut in the longitudinal direction showed a greater difference between coils; the material giving unacceptable wrinkling had a significantly higher moment curvature characteristic indicating substantial ageing. All materials showed some coil set and the bending properties depended on the direction in which the specimen was bent, i.e. in the same or opposite direction to the coil set. A finite element analysis was performed on the process which indicated significant plastic deformation in the flange, but very little in the web. Possible links between the unusual bending behaviour and oil canning in the web are suggested and the work indicates the desirability of performing free bending tests in addition to the customary tensile testing in roll forming applications.

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Roll-formability of cryo-rolled ultrafine aluminium sheet

Cited by 29 publications

References 15 publications

Special Rolling Techniques for Improvement of Mechanical Properties of Ultrafine‐Grained Metal Sheets: a Review

Special Rolling Techniques for Improvement of Mechanical Properties of Ultrafine‐Grained Metal Sheets: a Review

Enhanced ductility of ultra-fine grained metallic materials

Bending behaviour and oil canning in roll forming a steel channel

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