Experimental study of fracture behavior of magnesium single crystals

Kaushik, Vikas; Narasimhan, R.; Mishra, Raja K.

doi:10.1016/j.msea.2013.10.018

Cited by 86 publications

(58 citation statements)

References 23 publications

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“…2 (a-f) correspond to cracks along the basal, prismatic, pyramidal I and II planes with different crack front orientations favoring different dislocation nucleations. Cracks on twin interfaces may also be important, as suggested by recent experiments where twin related microcracks were observed in scanning electron microscope (SEM) micrograph of Mg alloy during uniaxial and controlled triaxial loadings [16] and three-point bending test of single crystal Mg [17]. Therefore, we examine two cracks ( Fig.…”

Section: Crack Geometries and Simulation Modelsmentioning

confidence: 94%

Brittle and ductile crack-tip behavior in magnesium

Curtin

2015

Acta Materialia

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Section: Crack Geometries and Simulation Modelsmentioning

confidence: 94%

Brittle and ductile crack-tip behavior in magnesium

Curtin

2015

Acta Materialia

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“…The low J c value for orientation B as compared to A despite their similarity was attributed to the presence of {1012} twins induced during specimen polishing which impeded the nucleation and growth of twins during the deformation of the specimen (Kaushik et al 2014). Thus, plastic dissipation was restricted to fewer twins and crack growth occurred at a low J c value due to plastic slip accumulation at the interface between the matrix and the prominent twin near the notch root.…”

Section: Introductionmentioning

confidence: 99%

“…To this end, Kaushik et al (2014) carried out fracture experiments using notched three point bend specimens of Mg single crystals having three different crystallographic orientations. In the first and second orientations, referred to as A and B, the normal to the flat surfaces of the notch was aligned along c-axis.…”

Section: Introductionmentioning

confidence: 99%

“…In order to address the questions posed by the experiments of Kaushik et al (2014), crystal plasticity based simulations which have been shown to predict mechanical response, formability and failure in the presence of slip and twinning (Graff et al 2007;Knezevic et al 2010;Izadbakhsh et al 2011;Fernandez et al 2011;Zhang and Joshi 2012) are adequate. It must be mentioned that to model individual twins and their interactions, atomistic or phase-field simulations (Kucherov and Tadmor 2007;Kim et al 2010;Tang et al 2011a;Hu et al 2010;Knap 2011, 2013) are required.…”

Section: Introductionmentioning

confidence: 99%

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Finite element simulations of notch tip fields in magnesium single crystals

2014

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Recent experiments using three point bend specimens of Mg single crystals have revealed that tensile twins of {1012}-type form profusely near a notch tip and enhance the fracture toughness through large plastic dissipation. In this work, 3D finite element simulations of these experiments are carried out using a crystal plasticity framework which includes slip and twinning to gain insights on the mechanics of fracture. The predicted load-displacement curves, slip and tensile twinning activities from finite element analysis corroborate well with the experimental observations. The numerical results are used to explore the 3D nature of the crack tip stress, plastic slip and twin volume fraction distributions near the notch root. The occurrence of tensile twinning is rationalized from the variation of normal stress ahead of the notch tip. Further, deflection of the crack path at twin-twin intersections observed in the experiments is examined from an energy standpoint by modeling discrete twins close to the notch root.

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“…Kaushik et al [280] performed fracture tests on notched Mg specimens corresponding to three lattice orientations. The results indicated the occurrence of profuse tensile twinning in all three orientations.…”

Section: Twinning Effect On Fatigue Behaviourmentioning

confidence: 99%

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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Experimental study of fracture behavior of magnesium single crystals

Cited by 86 publications

References 23 publications

Brittle and ductile crack-tip behavior in magnesium

Brittle and ductile crack-tip behavior in magnesium

Finite element simulations of notch tip fields in magnesium single crystals

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

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