The Experts below are selected from a list of 111 Experts worldwide ranked by ideXlab platform

M.r. Sharafutdinov - One of the best experts on this subject based on the ideXlab platform.

  • effect of post heat treatment on the phase composition and strength of laser welded joints of an al mg li Alloy
    Materials Science and Engineering A-structural Materials Properties Microstructure and Processing, 2019
    Co-Authors: A G Malikov, M.r. Sharafutdinov, Anatoliy Orishich, Natalia V Bulina, E V Karpov
    Abstract:

    Abstract In the present work, the effects of laser beam welding and post-weld heat treatment on the phase composition and mechanical properties of the 1424 Alloy (Al–Mg–Li) joints were investigated. Holding the joints at a certain temperature was followed by quenching and artificial aging. The structural studies were carried out using electron microscopy, conventional X-ray diffractometry, and synchrotron radiation diffractometry. The heat treatment conditions were optimized to favor the formation of strengthening phases in the welds, the presence of which imparted mechanical strength to the joints. For the first time, 1424 Al Alloy joints with a weld strength of σuts = 500 MPa have been obtained; this value of strength was achieved by applying post-weld annealing followed by quenching and artificial aging.

Mary A Wells - One of the best experts on this subject based on the ideXlab platform.

  • hot deformation behavior and processing map of a superlight dual phase mg li Alloy
    Journal of Alloys and Compounds, 2018
    Co-Authors: Gang Liu, Xiaodong Peng, Guobing Wei, Junwei Liu, Weidong Xie, We Xie, Ami Hadadzadeh, Ya Yang, Mary A Wells
    Abstract:

    Abstract Hot deformation behavior of a superlight dual phase Mg-9Li-3Al-2Y Alloy was investigated by developing constitutive equations and constructing processing maps. Constitutive relationship was established by the prediction of materials constants (α, β, n, Q and lnA) based on true stress-strain curves. Processing maps were constructed for Mg-9Li-3Al-2Y Alloy based on dynamic materials model (DMM). The instability domains occurred over a narrow temperature range of 423–450 K and strain rate range of 0.01–1s−1, and over a temperature range of 560–573 K and close to strain rate of 1s−1. The twinning in ɑ-Mg phase and cracks in the matrix were observed in the instability domains, the refined dynamic recrystallization (DRX) grains were formed in the regions with high efficiency values. It is undesirable to deform at high strain rates for mechanical properties because of the instability. Dynamic recrystallization occurs first in β-Li phases, and the Al2Y particles were conducive to the DRX process with particle stimulated nucleation effect. The DRX process of ɑ-Mg phase was retarded by β-Li phase. The DRXed grains of β-Li phase showed a random texture, while the basal poles of ɑ-Mg phase rotated towards the normal direction, which can enhance the further deformation. Based on constitutive relationship, processing map and texture evolution, the Mg-9Li-3Al-2Y Alloy is easy to suffer from deformation at a wide range of temperatures and strain rates.

  • microstructure evolution and simulation study of a duplex mg li Alloy during double change channel angular pressing
    Materials & Design, 2016
    Co-Authors: Guobing Wei, Xiaodong Peng, Junwei Liu, Weidong Xie, Yahya Mahmoodkhani, Amir Hadadzadeh, Mary A Wells
    Abstract:

    Abstract The dual-phase Mg–9Li–3Al–2Sr–2Y Alloy was extruded at 553 K using Double Change Channel Angular Pressing (DCCAP) with an extrusion ratio of 17. The commercial code DEFORM-3D was used to develop a numerical model for deformation of the investigated material and the strain distribution, damage and grain shape evolution were predicted. The accurate computation of the material flow and deformation was performed, of which the results showed good agreement with microscope observations and micro-hardness measurements on the deformed billet and extrudate. Results suggest that dynamic recrystallization (DRX) occurs during the deformation and leads to grain refinement during the DCCAP process. The tensile strength and elongation after fracture in middle part of the extrudate show optimum values of 246.6 MPa and 19.9%, respectively.

Zenji Horita - One of the best experts on this subject based on the ideXlab platform.

  • Long-time stability of metals after severe plastic deformation: Softening and hardening by self-annealing versus thermal stability
    Materials Science and Engineering A-structural Materials Properties Microstructure and Processing, 2018
    Co-Authors: Kaveh Edalati, Yuki Hashiguchi, Hideaki Iwaoka, Ruslan Z. Valiev, Hirotaka Matsunaga, Zenji Horita
    Abstract:

    Abstract Despite superior properties of ultrafine-grained (UFG) materials processed by severe plastic deformation (SPD), their thermal stability is a concern because of the supersaturated fractions of lattice defects. In this study, the microstructural stability of various UFG materials (2 Alloys and 15 pure metals) after SPD processing through the high-pressure torsion (HPT) were investigated at room temperature for up to 10 years. While most of the metals with high melting temperatures remained stable, a softening by self-annealing occurred in pure silver, gold and copper (with moderate melting temperatures), and an unusual hardening occurred in pure magnesium, Al-Zn Alloy and Mg-Li Alloy (with low melting temperatures). These softening/hardening behaviors by grain coarsening were attributed to the contribution of grain boundaries to dislocation activity or grain-boundary sliding, respectively. It was shown that the self-annealing was accelerated by increasing the processing pressure and strain and by decreasing the processing temperature and stacking fault energy, due to the enhancement of stored energy and/or atomic mobility.

  • ultrafine grained magnesium lithium Alloy processed by high pressure torsion low temperature superplasticity and potential for hydroforming
    Materials Science and Engineering A-structural Materials Properties Microstructure and Processing, 2015
    Co-Authors: Hirotaka Matsunoshita, Zenji Horita, Kaveh Edalati, Mitsuaki Furui
    Abstract:

    Abstract A Mg–Li Alloy with 8 wt% Li was processed by severe plastic deformation (SPD) through the process of high-pressure torsion (HPT) to achieve ultrafine grains with an average grain size of ~500 nm. Tensile testing with an initial strain rate of 10 −3  s −1 showed that the Alloy exhibited superplasticity at a temperature of 323 K or higher. Tensile testing in boiling water confirmed that the specimens were elongated to 350–480% at 373 K under the initial strain rates of 10 −3  s −1 to 1 0 −2  s −1 with a strain rate sensitivity of ~0.3. The current study suggests that not only superplastic forming but also superplastic hydroforming should be feasible after the grain refinement using the HPT method.

Guobing Wei - One of the best experts on this subject based on the ideXlab platform.

  • hot deformation behavior and processing map of a superlight dual phase mg li Alloy
    Journal of Alloys and Compounds, 2018
    Co-Authors: Gang Liu, Xiaodong Peng, Guobing Wei, Junwei Liu, Weidong Xie, We Xie, Ami Hadadzadeh, Ya Yang, Mary A Wells
    Abstract:

    Abstract Hot deformation behavior of a superlight dual phase Mg-9Li-3Al-2Y Alloy was investigated by developing constitutive equations and constructing processing maps. Constitutive relationship was established by the prediction of materials constants (α, β, n, Q and lnA) based on true stress-strain curves. Processing maps were constructed for Mg-9Li-3Al-2Y Alloy based on dynamic materials model (DMM). The instability domains occurred over a narrow temperature range of 423–450 K and strain rate range of 0.01–1s−1, and over a temperature range of 560–573 K and close to strain rate of 1s−1. The twinning in ɑ-Mg phase and cracks in the matrix were observed in the instability domains, the refined dynamic recrystallization (DRX) grains were formed in the regions with high efficiency values. It is undesirable to deform at high strain rates for mechanical properties because of the instability. Dynamic recrystallization occurs first in β-Li phases, and the Al2Y particles were conducive to the DRX process with particle stimulated nucleation effect. The DRX process of ɑ-Mg phase was retarded by β-Li phase. The DRXed grains of β-Li phase showed a random texture, while the basal poles of ɑ-Mg phase rotated towards the normal direction, which can enhance the further deformation. Based on constitutive relationship, processing map and texture evolution, the Mg-9Li-3Al-2Y Alloy is easy to suffer from deformation at a wide range of temperatures and strain rates.

  • Dynamic Recrystallization Behavior and Corrosion Resistance of a Dual-Phase Mg-Li Alloy
    MDPI AG, 2018
    Co-Authors: Gang Liu, Guobing Wei, Wen Xie, Yan Yang, Junwei Liu, Weidong Xie, Xiaodong Peng
    Abstract:

    The hot deformation and dynamic recrystallization behavior of the dual-phase Mg-9Li-3Al-2Sr-2Y Alloy had been investigated using a compression test. The typical dual-phase structure was observed, and average of grain size of as-homogenized Alloy is about 110 µm. It mainly contains β-Li, α-Mg, Al4Sr and Al2Y phases. The dynamic recrystallization (DRX) kinetic was established based on an Avrami type equation. The onset of the DRX process occurred before the peak of the stress–strain flow curves. It shows that the DRX volume fraction increases with increasing deformation temperature or decreasing strain rate. The microstructure evolution during the hot compression at various temperatures and strain rates had been investigated. The DRX grain size became larger with the increasing testing temperature or decreasing strain rate because the higher temperature or lower strain rate can improve the migration of DRX grain boundaries. The fully recrystallized microstructure can be achieved in a small strain due to the dispersed island-shape α-Mg phases, continuous the Al4Sr phases and spheroidal Al2Y particles, which can accelerate the nucleation. The continuous Al4Sr phases along the grain boundaries are very helpful for enhancing the corrosion resistance of the duplex structured Mg-Li Alloy, which can prevent the pitting corrosion and filiform corrosion

  • microstructure evolution and simulation study of a duplex mg li Alloy during double change channel angular pressing
    Materials & Design, 2016
    Co-Authors: Guobing Wei, Xiaodong Peng, Junwei Liu, Weidong Xie, Yahya Mahmoodkhani, Amir Hadadzadeh, Mary A Wells
    Abstract:

    Abstract The dual-phase Mg–9Li–3Al–2Sr–2Y Alloy was extruded at 553 K using Double Change Channel Angular Pressing (DCCAP) with an extrusion ratio of 17. The commercial code DEFORM-3D was used to develop a numerical model for deformation of the investigated material and the strain distribution, damage and grain shape evolution were predicted. The accurate computation of the material flow and deformation was performed, of which the results showed good agreement with microscope observations and micro-hardness measurements on the deformed billet and extrudate. Results suggest that dynamic recrystallization (DRX) occurs during the deformation and leads to grain refinement during the DCCAP process. The tensile strength and elongation after fracture in middle part of the extrudate show optimum values of 246.6 MPa and 19.9%, respectively.

  • microstructure and mechanical properties of superlight mg li al zn wrought Alloy
    Rare Metal Materials and Engineering, 2014
    Co-Authors: Xiaodong Peng, Junwei Jiang, Guobing Wei, Ao Zhang
    Abstract:

    Abstract Superlight Alloys, including Mg-7Li-3Zn, Mg-7Li-3Al and Mg-7Li-1.5Al-1.5Zn, were prepared using a resistance furnace under the protection of argon atmosphere. The microstructures and phases of the Alloys were studied by optical microscopy, scanning electronic microscopy (SEM), X-ray diffraction (XRD). The mechanical properties of these Alloys were measured by a tensile tester. The results show that the Zn and Al added in Mg-Li Alloy mainly dissolve in α-Mg phase and β-Li phase. However, there still exists a part of the Al and Mg compound such as Mg17Al12 which is mainly distributed discontinuously at α phase boundary while the most of them in the β phase are granular. The as-extruded Mg-7Li-3Al Alloy has the maximum tensile strength and yield strength of 239 MPa (34% higher than the as-cast) and 178 MPa (31% higher than the as-cast), respectively, and the maximum elongation reaches to 27% (93% higher than the as-cast).

A G Malikov - One of the best experts on this subject based on the ideXlab platform.

  • effect of post heat treatment on the phase composition and strength of laser welded joints of an al mg li Alloy
    Materials Science and Engineering A-structural Materials Properties Microstructure and Processing, 2019
    Co-Authors: A G Malikov, M.r. Sharafutdinov, Anatoliy Orishich, Natalia V Bulina, E V Karpov
    Abstract:

    Abstract In the present work, the effects of laser beam welding and post-weld heat treatment on the phase composition and mechanical properties of the 1424 Alloy (Al–Mg–Li) joints were investigated. Holding the joints at a certain temperature was followed by quenching and artificial aging. The structural studies were carried out using electron microscopy, conventional X-ray diffractometry, and synchrotron radiation diffractometry. The heat treatment conditions were optimized to favor the formation of strengthening phases in the welds, the presence of which imparted mechanical strength to the joints. For the first time, 1424 Al Alloy joints with a weld strength of σuts = 500 MPa have been obtained; this value of strength was achieved by applying post-weld annealing followed by quenching and artificial aging.

  • effect of heat treatment on mechanical and microstructural properties of the welded joint of the al mg li Alloy obtained by laser welding
    Journal of Applied Mechanics and Technical Physics, 2018
    Co-Authors: Anatoliy Orishich, A G Malikov, E V Karpov, N A Pavlov, I S Mesenzova
    Abstract:

    Laser welding of the 1420 Alloy of the Al–Mg–Li system is experimentally studied for the purpose of its optimization. Various modes of heat treatment of fixed joints obtained by means of laser welding are considered. Heat treatment modes that allow significant enhancement of the welded joint density as compared to the as-received Alloy are chosen. The ultimate relative elongation of samples after ageing is found to decrease by a factor of 3.