The Experts below are selected from a list of 13320 Experts worldwide ranked by ideXlab platform

Junichi Koike - One of the best experts on this subject based on the ideXlab platform.

  • internal Microstructure Observation of enhanced grain boundary sliding at room temperature in az31 magnesium alloy
    Materials Science and Engineering A-structural Materials Properties Microstructure and Processing, 2016
    Co-Authors: Daisuke Ando, Yuji Sutou, Junichi Koike
    Abstract:

    Abstract The origin of grain boundary sliding (GBS) is known to be slip-induced due to plastic incompatibility near the grain boundary at room temperature. In this study, the relationship between GBS and crystal orientation was investigated in AZ31 Mg alloy rolled sheets at room temperature. The GBS tendency was determined as related to basal dislocation slip where the GBS boundaries were generally located between the grains with respectively high and low or high and high Schmid factors for basal slip. The results indicate that GBS is attributed to the plastic incompatibility caused by anisotropic basal and prismatic slip. Furthermore, GBS was located in regions with localized deformation near grain boundaries. Cross-sectional focused ion beam/transmission electron microscopy (FIB/TEM) Observations of these regions revealed seriately arranged subgrains adjacent to a grain boundary. Therefore, we propose that RT-GBS in AZ31 can be caused by localized crystal rotation due to dynamic recover and recrystallization by stress concentration near the grain boundary but not ordinary GBS.

  • internal Microstructure Observation of enhanced grain boundary sliding at room temperature in az31 magnesium alloy
    Materials Science and Engineering A-structural Materials Properties Microstructure and Processing, 2016
    Co-Authors: Daisuke Ando, Yuji Sutou, Junichi Koike
    Abstract:

    Abstract The origin of grain boundary sliding (GBS) is known to be slip-induced due to plastic incompatibility near the grain boundary at room temperature. In this study, the relationship between GBS and crystal orientation was investigated in AZ31 Mg alloy rolled sheets at room temperature. The GBS tendency was determined as related to basal dislocation slip where the GBS boundaries were generally located between the grains with respectively high and low or high and high Schmid factors for basal slip. The results indicate that GBS is attributed to the plastic incompatibility caused by anisotropic basal and prismatic slip. Furthermore, GBS was located in regions with localized deformation near grain boundaries. Cross-sectional focused ion beam/transmission electron microscopy (FIB/TEM) Observations of these regions revealed seriately arranged subgrains adjacent to a grain boundary. Therefore, we propose that RT-GBS in AZ31 can be caused by localized crystal rotation due to dynamic recover and recrystallization by stress concentration near the grain boundary but not ordinary GBS.

H Z Guo - One of the best experts on this subject based on the ideXlab platform.

  • competition between dynamic recovery and recrystallization during hot deformation for tc18 titanium alloy
    Materials Science and Engineering A-structural Materials Properties Microstructure and Processing, 2015
    Co-Authors: Y Q Ning, Houquan Liang, H Z Guo, X Luo, J Zhang, K Tan
    Abstract:

    Abstract The competition between dynamic recovery (DRV) and recrystallization (DRX) during hot deformation has been investigated in the present paper. Isothermal compression experiment of TC18 titanium alloy was conducted for verification. The hot deformation mechanism for TC18 alloy has been identified as dislocation evolution from the stress exponent correspondence. Suitable descriptions to dislocation evolution under DRV/DRX have been obtained and validated by stress variation with DRX critical strain as the transition. Work-hardening behaviors correspond to the competition between DRX/DRV and segmented functions were constructed to describe the variation. The influence of α/β phase transformation and DRX evolution on dislocation evolution and work-hardening behaviors has been characterized with the Kocks–Mecking model developed. Power dissipation efficiency and Microstructure Observation were utilized to demonstrate the dependence of dynamic softening mechanism. The β necking phenomenon in DRX grains has been associated with the periodic competition between DRX and DRV.

  • dynamic softening behavior of tc18 titanium alloy during hot deformation
    Materials & Design, 2015
    Co-Authors: Y Q Ning, B C Xie, Houquan Liang, X M Yang, H Z Guo
    Abstract:

    Abstract Dynamic softening behavior of TC18 titanium alloy have been investigated in this paper based on isothermal compression experiment. Strain-rate sensitivity coefficient m and deformation activation energy Qdef under different deformation conditions have been calculated through Arrhenius constitutive model. The dependence of strain-rate sensitivity and activation energy on deformation parameters has been analyzed from the perspective of internal variables. A function of deformation temperature has been proposed to estimate the self-diffusion activation energy Qself for dual-phase titanium alloys. The dependence of DRX/DRV on deformation parameters has been demonstrated by novel methods. From comparisons between self-diffusion and deformation activation energy, deformation undergoing DRX has been identified with low strain rates and elevated temperatures. Finally, Microstructure Observation has been taken carried out to verify the applicability of the new methods. Meanwhile, Poliak–Jonas criterion and power dissipation efficiency distribution has been employed to discuss the dependence of softening behavior on deformation condition.

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

  • study on hot deformation behavior and intrinsic workability of 6063 aluminum alloys using 3d processing map
    Journal of Alloys and Compounds, 2017
    Co-Authors: Yang Liu, Cong Geng, Qiquan Lin, Yifeng Xiao, Wei Kang
    Abstract:

    Abstract Hot deformation in 6063 aluminum alloys was investigated by hot compression testing over the temperature range of 573–723 K with strain rates of 0.01–10 s−1 using a Gleeble 3500 thermal-mechanical simulator. Based on the experimental results, constitutive equations compensated with strain were developed to model the hot deformation behavior. The intrinsic workability was further analyzed by establishing three-dimensional processing maps. These maps were constructed based on dynamic materials model to delineate variations in power dissipation efficiency and flow instability domains. Combined with Microstructure Observation, recommended processing domains are predicated to be within the temperatures range of 673–723 K and strain rates range of 0.01–0.1 s−1. Under such conditions, the main softening mechanism is dynamic recrystallization. The results from these processing maps agree well with Microstructure Observation.

Y Q Ning - One of the best experts on this subject based on the ideXlab platform.

  • competition between dynamic recovery and recrystallization during hot deformation for tc18 titanium alloy
    Materials Science and Engineering A-structural Materials Properties Microstructure and Processing, 2015
    Co-Authors: Y Q Ning, Houquan Liang, H Z Guo, X Luo, J Zhang, K Tan
    Abstract:

    Abstract The competition between dynamic recovery (DRV) and recrystallization (DRX) during hot deformation has been investigated in the present paper. Isothermal compression experiment of TC18 titanium alloy was conducted for verification. The hot deformation mechanism for TC18 alloy has been identified as dislocation evolution from the stress exponent correspondence. Suitable descriptions to dislocation evolution under DRV/DRX have been obtained and validated by stress variation with DRX critical strain as the transition. Work-hardening behaviors correspond to the competition between DRX/DRV and segmented functions were constructed to describe the variation. The influence of α/β phase transformation and DRX evolution on dislocation evolution and work-hardening behaviors has been characterized with the Kocks–Mecking model developed. Power dissipation efficiency and Microstructure Observation were utilized to demonstrate the dependence of dynamic softening mechanism. The β necking phenomenon in DRX grains has been associated with the periodic competition between DRX and DRV.

  • dynamic softening behavior of tc18 titanium alloy during hot deformation
    Materials & Design, 2015
    Co-Authors: Y Q Ning, B C Xie, Houquan Liang, X M Yang, H Z Guo
    Abstract:

    Abstract Dynamic softening behavior of TC18 titanium alloy have been investigated in this paper based on isothermal compression experiment. Strain-rate sensitivity coefficient m and deformation activation energy Qdef under different deformation conditions have been calculated through Arrhenius constitutive model. The dependence of strain-rate sensitivity and activation energy on deformation parameters has been analyzed from the perspective of internal variables. A function of deformation temperature has been proposed to estimate the self-diffusion activation energy Qself for dual-phase titanium alloys. The dependence of DRX/DRV on deformation parameters has been demonstrated by novel methods. From comparisons between self-diffusion and deformation activation energy, deformation undergoing DRX has been identified with low strain rates and elevated temperatures. Finally, Microstructure Observation has been taken carried out to verify the applicability of the new methods. Meanwhile, Poliak–Jonas criterion and power dissipation efficiency distribution has been employed to discuss the dependence of softening behavior on deformation condition.

Houquan Liang - One of the best experts on this subject based on the ideXlab platform.

  • hot deformation behavior and process parameter optimization of ti22al25nb using processing map
    Rare Metals, 2016
    Co-Authors: Jingli Zhang, Hongzhen Guo, Houquan Liang
    Abstract:

    The hot deformation behavior of Ti22Al25Nb was investigated by hot compression test. The flow stress–strain curves can be divided into two types: conventional dynamic recrystallization (DRX) and discontinuous DRX. The different softening mechanism and Microstructure Observation of conventional DRX and discontinuous DRX were analyzed. The processing map (PM) of Ti22Al25Nb was built to predict the safe deformation region. The optimal low strain rate domain (DOM I) with high power dissipation efficiency indicates the complete DRX. Additionally, in the high strain rate and low-temperature domain (DOM III), the power dissipation efficiency is low and some adiabatic shear bands and glide bands are observed, which are unsafe and should be avoided. Finally, the DRX map was established. In DOM I, it reveals low dislocation density and high DRX content, which is in agreement with PM.

  • competition between dynamic recovery and recrystallization during hot deformation for tc18 titanium alloy
    Materials Science and Engineering A-structural Materials Properties Microstructure and Processing, 2015
    Co-Authors: Y Q Ning, Houquan Liang, H Z Guo, X Luo, J Zhang, K Tan
    Abstract:

    Abstract The competition between dynamic recovery (DRV) and recrystallization (DRX) during hot deformation has been investigated in the present paper. Isothermal compression experiment of TC18 titanium alloy was conducted for verification. The hot deformation mechanism for TC18 alloy has been identified as dislocation evolution from the stress exponent correspondence. Suitable descriptions to dislocation evolution under DRV/DRX have been obtained and validated by stress variation with DRX critical strain as the transition. Work-hardening behaviors correspond to the competition between DRX/DRV and segmented functions were constructed to describe the variation. The influence of α/β phase transformation and DRX evolution on dislocation evolution and work-hardening behaviors has been characterized with the Kocks–Mecking model developed. Power dissipation efficiency and Microstructure Observation were utilized to demonstrate the dependence of dynamic softening mechanism. The β necking phenomenon in DRX grains has been associated with the periodic competition between DRX and DRV.

  • dynamic softening behavior of tc18 titanium alloy during hot deformation
    Materials & Design, 2015
    Co-Authors: Y Q Ning, B C Xie, Houquan Liang, X M Yang, H Z Guo
    Abstract:

    Abstract Dynamic softening behavior of TC18 titanium alloy have been investigated in this paper based on isothermal compression experiment. Strain-rate sensitivity coefficient m and deformation activation energy Qdef under different deformation conditions have been calculated through Arrhenius constitutive model. The dependence of strain-rate sensitivity and activation energy on deformation parameters has been analyzed from the perspective of internal variables. A function of deformation temperature has been proposed to estimate the self-diffusion activation energy Qself for dual-phase titanium alloys. The dependence of DRX/DRV on deformation parameters has been demonstrated by novel methods. From comparisons between self-diffusion and deformation activation energy, deformation undergoing DRX has been identified with low strain rates and elevated temperatures. Finally, Microstructure Observation has been taken carried out to verify the applicability of the new methods. Meanwhile, Poliak–Jonas criterion and power dissipation efficiency distribution has been employed to discuss the dependence of softening behavior on deformation condition.