Flow softening, twinning and dynamic recrystallization in AZ31 magnesium

Liu, X.; Jonas, John J.; Li, L.X.; Zhu, Biwu

doi:10.1016/j.msea.2013.06.074

Cited by 86 publications

(12 citation statements)

References 31 publications

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“…In Fig. 11, any twining cannot be observed under both conditions, which is similar with the result of Stanford [38], who observed very little twining at 423 K and considered that it would not form deformation twins when the temperature was higher than 523 K. The reason is that the rolled AZ31B sheets have a strong basal texture, and when the specimens were uniaxial stretched, the caxis was under a compressive deformation; then, because the {1011} compression twining is hard to be formed in this temperature range, none deformation twins were formed, contrasting by the fact that the {1012} extension twining even occurred at 723 K [39].…”

Section: Resultsmentioning

confidence: 99%

Effect of pulsed current on the deformation behavior of AZ31B magnesium alloy

Liu

Dong

Xie

et al. 2015

Materials Science and Engineering: A

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Section: Resultsmentioning

confidence: 99%

Effect of pulsed current on the deformation behavior of AZ31B magnesium alloy

Liu

Dong

Xie

et al. 2015

Materials Science and Engineering: A

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“…However, Mg alloys exhibit a strong preference for mechanical twinning because the twinning has a lower threshold stress than <c + a> slip [1-4](L. . Therefore, twinning plays a vital role during deformation (Liu, Jonas, Li, & Zhu, 2013). It is well known that there are typically two types of deformation twins which form in Mg; one type are {10 2} extension twins and the other are {10 1} contraction twins (Yoo, 1981).…”

Section: Introductionmentioning

confidence: 99%

The cold-rolling behaviour of AZ31 tubes for fabrication of biodegradable stents

Yao-wu

Kent

Wang

et al. 2014

Journal of the Mechanical Behavior of Biomedical Materials

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The cold-rolling behaviour of AZ31 tubes for fabrication of biodegradable stents, Journal of the Mechanical Behavior of Biomedical Materials, http://dx.doi.org/10. 1016/j.jmbbm.2014.07.026 This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting galley proof before it is published in its final citable form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain. AbstractMg alloys are receiving considerable attention for biomedical stents due to their combination of good mechanical properties and high biodegradability. Cold rolling is necessary to process Mg alloy tubes before final drawing and fabrication of the magnesium stents. In this paper, cold-rolled tubes were subjected to a crosssectional reduction rate (ε) of up to 19.7%, and were further processed at various ratios of wall-thickness to diameter reduction (Q) from 0 to 2.24 with a constant ε of 19.7%. The results show that the cold-rolled tubes exhibited a rise in ultimate tensile strength (UTS), yield strength (YS), and a reduction in elongation as ε increased from 5.5% to 19.7%. UTS, YS and elongation decreased when Q was increased from 0 to 2.24.Mechanical twinning was observed and analysed. Extension twins increased with increasing ε and were almost saturated at an ε of 16.5%. Extension twins play an important role in determining the evolution of mechanical behaviour in the case of increasing ε, whilst contraction/double twins and secondary extension twins have a large effect on mechanical behaviour in the case of varying Q. The results indicate that the proportions and types of twins play a major role in determining the mechanical behaviour of the AZ31 tubes.

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“…During the processing of magnesium fine tubes, the activation of twins greatly depends on the texture [67][68][69]. Liu et al [70,71] studied the relationship between texture and deformation mode and concluded that the shape of the stress-strain curve is determined by the type of twinning that occurs and by when the twins are activated. Jiang, et al [72] conducted a study to determine the twinning modes and texture development under different strain paths.…”

Section: Microstructural Evolution Of Magnesium Alloys In the Processmentioning

confidence: 99%

“…However, Mg alloys exhibit a strong preference for mechanical twinning because the twinning has a lower threshold stress than <c + a> slip [1][2][3][4][139]. Therefore, twinning plays a vital role during deformation [70]. It is well known that there are typically two types of deformation twins which form in Mg; one type are {101 ̅ 2} extension twins and the other are {101 ̅ 1} contraction twins [54].…”

Section: Introductionmentioning

confidence: 99%

“…Twinning activity can be investigated in order to explain the evolution of mechanical behaviour of Mg tubes during cold-rolling. Liu et al [70,71] studied the relationship between texture and deformation mode and concluded that the shape of the flow curve was determined by the type of twinning that occurs and by when the twins were activated. Variations in the strain hardening behaviour can be attributed to the influence of mechanical twinning.…”

Section: Introductionmentioning

confidence: 99%

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Mechanical and microstructural characterisation in the processing of biomedical metallic fine tubes

Yao-wu¹

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Fine tube stents are used for maintaining localised flow in stenotic blood vessels. Elasticity and plasticity for expansion, rigidity for resisting bending under force and strength to prevent unexpected failure, are required properties of the tubes from which these stents are formed. Biomedical metastable β titanium alloys have been developed as implant materials for a large number of biomedical applications due to a combination of favourable characteristics, e.g. good biocompatibility, excellent toughness and corrosion resistance. A metastable β alloy, Ti-25Nb-3Mo-3Zr-2Sn, has been developed without toxic alloying elements, which is a promising candidate material for stent applications. Metallic materials used for stents are commonly not biodegradable and implanted in the vessel permanently, which may provoke in-stent restenosis and stent thrombosis. In order to remove the implanted materials after service, biodegradable materials, absorbed by the body slowly, are also a field of research interest. Magnesium alloys have been used in studies for biomedical stent applications as a new biodegradable material. Magnesium stents can reopen the blocked blood vessels temporarily before degrading in physiological environments. In addition to the biodegradable characteristics, their mechanical properties are reasonable. The Mg-3Al-1Zn (AZ31) alloy is the subject of some research on the processing of biomedical magnesium alloys as it is a commonly available commercial alloy. Consequently, the Ti-25Nb-3Mo-3Zr-2Sn alloy and the AZ31 magnesium alloy have been used in this thesis to investigate the evolution of mechanical properties and microstructure in the processing of fine tubes.The deformation mechanisms during cold deformation of metastable β titanium alloys are mainly associated with martensitic phase transformations and mechanical twinning. It has been reported that stress-induced phase transformations and {112}〈111〉, {332}〈113〉 twinning modes may be activated under different stress states in metastable β titanium alloys. They can exhibit varying elasticity, Young's modulus and strain hardening behaviour. Because the martensitic start temperature is below room temperature for most metastable β titanium alloys, the α″ martensitic transformation can easily occur under a small amount of external stress. Mechanical twins were reported to hinder slip and dislocation motion thereby increasing the strain hardening rate. The development of β and α″ texture during processing is another critical influence on the mechanical properties of fine tubes. Therefore, studies on the martensitic transformation, mechanical twins and texture evolution is of significance in order to understand the processing of β titanium fine tubes.ii Magnesium alloys deform through the formation of a large amount of mechanical twins due to the relatively low critical stress to activate twinning in comparison with 〈 + 〉 slip. There are typically two primary mechanical twinning modes for magnesium alloys, {101 ̅ 2} extension twins and {101 ̅ 1} cont...

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Flow softening, twinning and dynamic recrystallization in AZ31 magnesium

Cited by 86 publications

References 31 publications

Effect of pulsed current on the deformation behavior of AZ31B magnesium alloy

Effect of pulsed current on the deformation behavior of AZ31B magnesium alloy

The cold-rolling behaviour of AZ31 tubes for fabrication of biodegradable stents

Mechanical and microstructural characterisation in the processing of biomedical metallic fine tubes

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