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A Model of Dynamic Recrystallization in Alloys during High Strain Plastic Deformation 被引量:7
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作者 Qiang LI and Yongbo XU(State Key Laboratory for Fatigue and Fracture of Materials, Institute of Metal Research, Chinese Academy of Sciences,Shenyang 110015, China) To whom correspondence should be addressed Present address: Analysis Cener, School of Mater 《Journal of Materials Science & Technology》 SCIE EI CAS CSCD 1999年第5期435-438,共4页
Recrystallized grains, less than 200 nm in diameter were observed in heavily shear zones of a high strength low alloy steel and a Ni-based alloy, and Also grain refinement, less than 3 μm in diameter was made in high... Recrystallized grains, less than 200 nm in diameter were observed in heavily shear zones of a high strength low alloy steel and a Ni-based alloy, and Also grain refinement, less than 3 μm in diameter was made in high purity aluminum by ECAE at ambient temperature. The experimental results showed that high strain rate and large deformation could induce dynamic recrystallization.Based on dislocation dynamics and grain orientation change enhanced by plastic deformation,a model for the recrystallization process is developed. The model is used to explain the ultra fine grains which are formed at a temperature still much lower than that for the conventional recrystallization 展开更多
关键词 FIGURE A model of Dynamic recrystallization in Alloys during High Strain Plastic Deformation
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Dynamic recrystallization behavior of burn resistant titanium alloy Ti-25V-15Cr-0.2Si
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作者 鲁世强 欧阳德来 +1 位作者 崔霞 王克鲁 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2016年第4期1003-1010,共8页
Dynamic recrystallization (DRX) behavior in β phase region for the burn resistant titanium alloy Ti?25V?15Cr?0.2Si was investigated with a compression test in the temperature range of 950?1100 °C and the strain ... Dynamic recrystallization (DRX) behavior in β phase region for the burn resistant titanium alloy Ti?25V?15Cr?0.2Si was investigated with a compression test in the temperature range of 950?1100 °C and the strain rate of 0.001?1 s?1. The results show that deformation mechanism of this alloy in hot deformation is dominated by DRX, and new grains of DRX are evolved by bulging nucleation mechanism as a predominant mechanism. DRX occurs more easily with the decrease of strain rate and the increase of deformation temperature. Grain refinement is achieved due to DRX during the hot deformation at strain rate range of 0.01?0.1 s?1 and temperature range of 950?1050 °C. DRX grain coarsening is observed for the alloy deformed at the higher temperatures of 1100 °C and the lower strain rates of 0.001 s?1. Finally, in order to determine the recrystallized fraction and DRX grain size under different deformation conditions, the prediction models of recrystallization kinetics and recrystallized grain sizes were established. 展开更多
关键词 burn resistant titanium alloy deformed microstructure deformation mechanism dynamic recrystallization prediction models
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Hot-deformation kinetics analysis and extrusion parameter optimization of a dilute rare-earth free magnesium alloy
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作者 Qinghang Wang Haowei Zhai +5 位作者 Zhaoyang Jin Junjie He Qin Yang Wenjun Liu Yulong Li Daolun Chen 《Journal of Magnesium and Alloys》 SCIE EI CAS CSCD 2023年第9期3302-3322,共21页
The fundamental research on thermo-mechanical conditions provides an experimental basis for high-performance Mg-Al-Ca-Mn alloys.However, there is a lack of systematical investigation for this series alloys on the hot-... The fundamental research on thermo-mechanical conditions provides an experimental basis for high-performance Mg-Al-Ca-Mn alloys.However, there is a lack of systematical investigation for this series alloys on the hot-deformation kinetics and extrusion parameter optimization. Here, the flow behavior, constitutive model, dynamic recrystallization(DRX) kinetic model and processing map of a dilute rare-earth free Mg-1.3Al-0.4Ca-0.4Mn(AXM100, wt.%) alloy were studied under different hot-compressive conditions. In addition, the extrusion parameter optimization of this alloy was performed based on the hot-processing map. The results showed that the conventional Arrhenius-type strain-related constitutive model only worked well for the flow curves at high temperatures and low strain rates. In comparison, using the machine learning assisted model(support vector regression, SVR) could effectively improve the accuracy between the predicted and experimental values. The DRX kinetic model was established, and a typical necklace-shaped structure preferentially occurred at the original grain boundaries and the second phases. The DRX nucleation weakened the texture intensity, and the further growth caused the more scattered basal texture. The hot-processing maps at different strains were also measured and the optimal hot-processing range could be confirmed at the deformation temperatures of 600~723 K and the strain rates of 0.018~0.563 s^(-1). Based on the optimum hot-processing range, a suitable extrusion parameter was considered as 603 K and 0.1 mm/s and the as-extruded alloy in this parameter exhibited a good strength-ductility synergy(yield strength of ~ 232.1 MPa, ultimate strength of ~ 278.2 MPa and elongation-to-failure of ~ 20.1%). Finally, the strengthening-plasticizing mechanisms and the relationships between the DRXed grain size, yield strength and extrusion parameters were analyzed. 展开更多
关键词 Mg-Al-Ca-Mn alloy Constitutive model Dynamic recrystallization kinetic model Extrusion parameter optimization Strengthening-plasticizing mechanisms
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Microstructure homogeneity regulation of 7050 aluminum forgings by surface cumulative plastic deformation 被引量:1
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作者 Jian-liang HU Zi-han ZHAO +4 位作者 Meng-xiao DONG Huan WANG Miao JIN Shi-quan HUANG Hong BO 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2022年第9期2814-2827,共14页
To regulate the microstructure homogeneity of large aluminum structural forgings for aircraft,the surface cumulative plastic deformation was proposed.The microstructure of 7050 aluminum forgings after the surface cumu... To regulate the microstructure homogeneity of large aluminum structural forgings for aircraft,the surface cumulative plastic deformation was proposed.The microstructure of 7050 aluminum forgings after the surface cumulative plastic deformation was investigated by electron backscatter diffraction(EBSD),transmission electron microscopy(TEM),and X-ray diffraction(XRD).The results showed that the microstructure evolution of 7050 aluminum forgings was more sensitive to the deformation temperature than the strain rate.The dislocation density continued to increase with the decrease of the deformation temperature and the increase of the strain rate.Dislocation density and stored energy were accumulated by the surface cumulative plastic deformation.Besides,a static recrystallization(SRX)model of 7050 aluminum forgings was established.The SRX volume fraction calculated by this model was in good agreement with the experimental results,which indicated that the model could accurately describe the SRX behavior of 7050 aluminum forgings during the surface cumulative plastic deformation. 展开更多
关键词 microstructure homogeneity regulation surface cumulative plastic deformation dislocation density static recrystallization model
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Hot deformation characteristics of as-cast high-Cr ultra-super-critical rotor steel with columnar grains 被引量:4
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作者 Zong-ye Ding Qiao-dan Hu +1 位作者 Long Zeng Jian-guo Li 《International Journal of Minerals,Metallurgy and Materials》 SCIE EI CAS CSCD 2016年第11期1275-1285,共11页
Isothermal hot compression tests of as-cast high-Cr ultra-super-critical(USC) rotor steel with columnar grains perpendicular to the compression direction were carried out in the temperature range from 950 to 1250... Isothermal hot compression tests of as-cast high-Cr ultra-super-critical(USC) rotor steel with columnar grains perpendicular to the compression direction were carried out in the temperature range from 950 to 1250°C at strain rates ranging from 0.001 to 1 s^(-1). The softening mechanism was dynamic recovery(DRV) at 950°C and the strain rate of 1 s^(-1), whereas it was dynamic recrystallization(DRX) under the other conditions. A modified constitutive equation based on the Arrhenius model with strain compensation reasonably predicted the flow stress under various deformation conditions, and the activation energy was calculated to be 643.92 kJ ×mol^(-1). The critical stresses of dynamic recrystallization under different conditions were determined from the work-hardening rate(θ)–flow stress(σ) and-θ/σ–σ curves. The optimum processing parameters via analysis of the processing map and the softening mechanism were determined to be a deformation temperature range from 1100 to 1200°C and a strain-rate range from 0.001 to 0.08 s^(-1), with a power dissipation efficiency η greater than 31%. 展开更多
关键词 rotor steel columnar grains dynamic recrystallization constitutive models critical conditions processing maps
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High Temperature Deformation Behavior of 4340 Steel: Activation Energy Calculation and Modeling of Flow Response 被引量:5
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作者 S V Sajadifar G G Yapici +1 位作者 M Ketabchi B Bemanizadeh 《Journal of Iron and Steel Research International》 SCIE EI CAS CSCD 2013年第12期133-139,共7页
The 4340 steel is extensively utilized in several industries including automotive and aerospace for manufac- turing a large number of structural components. Due to the importance of thermo-mechanical processing in the... The 4340 steel is extensively utilized in several industries including automotive and aerospace for manufac- turing a large number of structural components. Due to the importance of thermo-mechanical processing in the pro- duction of steels, the dynamic recrystallization (DRX) characteristics of 4340 steel were investigated. Namely, hot compression tests on 4340 steel have been performed in a temperature range of 900-- 1200 ℃ and a strain rate range of 0.01--1 s-1 and the strain of up to 0.9. The resulting flow stress curves show the occurrence of dynamic recrys- tallization. The flow stress values decrease with the increase of deformation temperature and the decrease of strain rate. The microstrueture of 4340 steel after deformation has been studied and it is suggested that the evolution of DRX grain structures can be accompanied by considerable migration of grain boundaries. The constitutive equations were developed to model the hot deformation behavior. Finally based on the classical stress-dislocation relations and the kinematics of the dynamic recrystallization; the flow stress constitutive equations for the dynamic recovery period and dynamic reerystallization period were derived for 4340 steel, respectively. The validity of the model was demon- strated by demonstrating the experimental data with the numerical results with reasonable agreement. 展开更多
关键词 4340 steel hot deformation activation energy dynamic recrystallization modeling strain rate sen- sitivity
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Dynamic recrystallization behaviour of H13-mod steel 被引量:3
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作者 Chang-min Li Yuan-biao Tan Fei Zhao 《Journal of Iron and Steel Research International》 SCIE EI CAS CSCD 2020年第9期1073-1086,共14页
H13-mod steel developed after optimizing the composition and heat treatment process exhibits good hardness and impact toughness and can be used as a shield machine hob.Based on the Avrami equation,the dynamic recrysta... H13-mod steel developed after optimizing the composition and heat treatment process exhibits good hardness and impact toughness and can be used as a shield machine hob.Based on the Avrami equation,the dynamic recrystallization(DRX)behaviour of H13-mod steel during hot compression was studied in the temperature of 900-1150°C and strain rate ranges of 0.01-10 s^-1.A DRX model and finite element software were used to study DRX behaviour of H13-mod steel.Significant DRX was found at both low and high strain rates.Electron backscatter diffraction and optical microscopy analyses found different DRX nucleation mechanisms at low and high strain rates under different deformations.At a low strain rate,the nucleation was dominated by the strain-induced grain boundary migration,whereas the subgrain coalescence mechanism was dominant at a high strain rate.Moreover,dynamic recovery occurred in both processes.In addition,it was easier to obtain small and uniform equiaxed grains at high strain rates than at low strain rates. 展开更多
关键词 H13-mod steel Dynamic recrystallization Dynamic recrystallization volume fraction model Finite element simulation Nucleation mechanism
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Modeling the Completely Recrystallized Grain Growth of NiCrMoV Rotor Steel
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作者 陈飞 李翠冬 崔振山 《Journal of Shanghai Jiaotong university(Science)》 EI 2015年第5期600-605,共6页
The present study focuses on the completely recrystallized grain growth of NiCrMoV steel.All the samples were austenitised at 1250℃ for 5min,and then were compressed with strain rate of 0.01s^(-1) and finial strain o... The present study focuses on the completely recrystallized grain growth of NiCrMoV steel.All the samples were austenitised at 1250℃ for 5min,and then were compressed with strain rate of 0.01s^(-1) and finial strain of 0.8.Once the compression completed,the specimens were held for different time before water quenching.Based on the experimental results,the completely recrystallized grain growth model was established and the effects of temperature and holding time on austenite grain size were investigated.Comparison between the experimental and predicted results was carried out.A good agreement between the experimental and predicted results verifies the developed model. 展开更多
关键词 NiCrMoV steel recrystallized grain growth modeling
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