Constitutive analysis of wrought Mg-Gd magnesium alloys during hot compression at elevated temperatures

Barezban, Mohammad Hossein; Mirzadeh, Hamed; Roumina, R.; Mahmudi, R.

doi:10.1016/j.jallcom.2019.03.383

Cited by 74 publications

(21 citation statements)

References 54 publications

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“…[5][6][7][8] Generally, the hot workability of alloys are significantly influenced by deformation parameters. [9][10][11] Constitutive models are usually inserted into finite element software to simulate the variations of flow stresses with deformation parameters. [12][13][14] In a recent critical review, [9] three types of constitutive models were summarized, i.e., phenomenological models, [15][16][17][18][19] physically based models, [20][21][22][23][24][25][26] and artificial intelligence models.…”

Section: Introductionmentioning

confidence: 99%

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Hot Tensile Deformation Mechanism and Dynamic Softening Behavior of Ti–6Al–4V Alloy with Thick Lamellar Microstructures

Lin

Pang

et al. 2019

Adv Eng Mater

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The deformation mechanisms and dynamic softening behavior of a Ti–6Al–4V alloy with thick lamellar microstructures are studied by uniaxial hot tensile tests. The true stress first rapidly reaches a peak value because of the rapid dislocations proliferation and tangle, and then gradually decreases due to the dynamic softening with raising the deformation amount. The dynamic softening behavior is mainly induced by the severe dynamic globularization of lamellar α phases. The globularization of α phase is always accompanied by the formation of high‐angle grain boundaries (HAGBs). The fraction of globularized α phases increases with the increasing deformation temperature. The fracture mechanism is microvoid coalescence, i.e., in the initial stage of tensile deformation, the microvoids begin to emerge. With the increasing deformation amount, the number of microvoids increases, and the microvoids accumulate and accelerate to propagate until the final fracture. According to the experimental flow stress curves, a modified Arrhenius‐type equation and a Hensel–Spittel (HS) model are developed to forecast the flow stresses. The average absolute relative error of the established strain‐compensated Arrhenius‐type (SCAT) and HS models are 6.108% and 3.385%, respectively. Both models can be well used to describe the hot tensile flow characteristics of the Ti–6Al–4V alloy with thick lamellar microstructures.

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Section: Introductionmentioning

confidence: 99%

“…Generally, the hot workability of alloys are significantly influenced by deformation parameters . Constitutive models are usually inserted into finite element software to simulate the variations of flow stresses with deformation parameters .…”

Section: Introductionmentioning

confidence: 99%

Hot Tensile Deformation Mechanism and Dynamic Softening Behavior of Ti–6Al–4V Alloy with Thick Lamellar Microstructures

Lin

Pang

et al. 2019

Adv Eng Mater

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“…[38] For the n value in the range of 2 to 2.5, grain boundary sliding (GBS) has been suggested to be the operating deformation mechanism. [20] Barezban et al [39] obtained a hyperbolic-sine exponent of 3 for a hot extruded binary Mg-1.5Gd alloy after hot compression deformation in the temperature range of 573 K to 723 K and strain rate of 0.0001 s À1 to 0.1 s À1 . They suggested that viscous glide of dislocations was the controlling deformation mechanism due to segregation of solute Gd atoms at dislocations.…”

Section: ½11mentioning

confidence: 99%

Effect of Ag Addition on the Hot Deformation, Constitutive Equations and Processing Maps of a Hot Extruded Mg-Gd-Y Alloy

Rezaei

Mahmudi

Logé

2020

Metall Mater Trans A

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Hot deformation behavior of the extruded Mg-6Gd-3Y (GW63) and Mg-6Gd-3Y-1Ag (GW63-1Ag) alloys was assessed by shear punch testing (SPT) method in the temperature range of 623 K to 723 K and shear strain rate of 1.6 9 10 À2 to 1.3 9 10 À1 s À1. Microstructural examinations showed that Ag addition decreased the initial grain size from 10.1 to 2.9 lm. According to the hot deformation results, hyperbolic-sine exponents (n-values) of 3.39 and 2.54 were obtained for the Ag-free and Ag-containing alloys, respectively. The corresponding activation energies were found to be 321 and 178 kJ mol À1 for these alloys. Therefore, the controlling deformation mechanisms were defined as viscous glide of dislocation for the Mg-6Gd-3Y alloy and grain boundary sliding for Mg-6Gd-3Y-1Ag. Processing maps were developed based on the dynamic material model (DMM) to determine the flow instability domains during hot deformation. Accordingly, the optimum hot working conditions were found to be in the temperature range of 655 K to 723 K and shear strain rate of 3.3 9 10 À2 to 1.3 9 10 À1 s À1 for the GW63-1Ag alloy, whereas the safe deformation window for the GW63 alloy was narrowed down to a temperature range of 665 K to 705 K and shear strain rate of 7.2 9 10 À2 to 1.3 9 10 À1 s À1. The Ag-containing alloy exhibited flow instability regions only at low temperatures and high strain rates. On the other hand, the Ag-free alloy demonstrated other instability domains comprising the formation of mechanical twins and cracking. Electron back-scattered diffraction analysis was utilized to correlate the microstructural evolution of the alloys after shear deformation to the hot working parameters. Continuous dynamic recrystallization was suggested as the main mechanism for generation of the dynamically recrystallized grains during hot deformation of both alloys.

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“…Hence, the mechanical properties of magnesium and its alloy were low formability, limited ductility and premature failure no mater quasi-static or dynamic deformation [ 5 , 6 , 7 ]. However, compared with room temperature conditions, the deformation mechanisms of magnesium and its alloys were significantly different and complex under high temperatures [ 8 , 9 , 10 , 11 , 12 , 13 , 14 , 15 , 16 , 17 , 18 , 19 ]. According to the extreme requirement of the magnesium alloy structure application, the knowledge of their mechanical response and microstructure evolution under a high strain rate and elevated temperature were significantly important [ 20 , 21 , 22 ].…”

Section: Introductionmentioning

confidence: 99%

Microstructural Characteristics and Subsequent Soften Mechanical Response in Transverse Direction of Wrought AZ31 with Elevated Compression Temperature

Yang

Zhang

et al. 2021

Materials

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In order to investigate the effect of temperature on the microstructure evolution and mechanical response in the transverse direction of a wrought AZ31 (AZ31-TD) alloy under a high strain rate, the dynamic compression was conducted using Split Hopkinson Pressure Bar (SHPB) apparatus and a resistance-heated furnace under 1000 s−1 at 20–250 °C. By combining optical and EBSD observations, the microstructure’s evolution was specifically analyzed. With the help of theoretically calculated Schmid Factors (SF) and Critical Resolved Shear Stress (CRSS), the activation and development deformation mechanisms are systematically discussed in the current study. The results demonstrated that the stress–strain curves are converted from a sigmoidal curve to a concave-down curve, which is caused by the preferentially and main deformation mechanism {101¯2} tension twinning gradually converting to simultaneously exist with the deformation mechanism of a non-basal slip at an elevated temperature, then completing with each other. Finally, the dynamic recrystallization (DRX) and non-basal slip are largely activated and enhanced by temperature elevated to weaken the {101¯2} tension twinning.

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Constitutive analysis of wrought Mg-Gd magnesium alloys during hot compression at elevated temperatures

Cited by 74 publications

References 54 publications

Hot Tensile Deformation Mechanism and Dynamic Softening Behavior of Ti–6Al–4V Alloy with Thick Lamellar Microstructures

Hot Tensile Deformation Mechanism and Dynamic Softening Behavior of Ti–6Al–4V Alloy with Thick Lamellar Microstructures

Effect of Ag Addition on the Hot Deformation, Constitutive Equations and Processing Maps of a Hot Extruded Mg-Gd-Y Alloy

Microstructural Characteristics and Subsequent Soften Mechanical Response in Transverse Direction of Wrought AZ31 with Elevated Compression Temperature

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