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Effect of Dynamic Strain Aging on Hardness in the Heat-Affected Zone of SUS316 Steel Welds
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作者 Lina Yu Kazutoshi Nishimoto Kazuyoshi Saida 《材料科学与工程(中英文A版)》 2023年第1期13-25,共13页
DSA(dynamic strain aging)phenomenon in SUS316 steel was investigated using isothermal and non-isothermal tensile tests of simulated HAZ(heat-affected zone)thermal cycles.Isothermal tensile tests were performed on SUS3... DSA(dynamic strain aging)phenomenon in SUS316 steel was investigated using isothermal and non-isothermal tensile tests of simulated HAZ(heat-affected zone)thermal cycles.Isothermal tensile tests were performed on SUS316 in the peak temperature range of 20-700°C,with strain rates varying from 4.2×10^(-3)to 4.2×10^(-5)s^(-1).Based on the appearance of discontinuous plastic flows,expressed as serrations,and the hardening phenomenon of the tensile samples,the conditions for the occurrence of DSA in the SUS316 steel were investigated.Furthermore,the extent of hardening due to DSA was evaluated by comparing the hardness values of the SUS316 and SUS316EHP steels after the tensile tests.To confirm the effect of DSA on hardness in the HAZ of the welded SUS316 steel,non-isothermal tensile tests of the simulated HAZ thermal cycles were performed using a Thermec Master.The relationship between the increase in Vickers hardness due to DSA and the strain in the HAZ was determined;the effect of DSA on hardness in the HAZ could be predicted.The DSA in SUS316 steel was found to be mainly attributed to the dynamic interaction of dislocations with C and N interstitial atoms during high-temperature deformation. 展开更多
关键词 dynamic strain aging HARDNESS SERRATION heat-affected zone SUS316
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Improving Tribological Performance of Gray Cast Iron by Laser Peening in Dynamic Strain Aging Temperature Regime 被引量:5
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作者 FENG Xu ZHOU Jianzhong +3 位作者 MEI Yufen HUANG Shu SHENG Jie ZHU Weili 《Chinese Journal of Mechanical Engineering》 SCIE EI CAS CSCD 2015年第5期904-910,共7页
A high and stable brake disc friction coefficient is needed for automobile safety, while the coefficient degrades due to elevated temperature during the braking process. There is no better solution except changes in m... A high and stable brake disc friction coefficient is needed for automobile safety, while the coefficient degrades due to elevated temperature during the braking process. There is no better solution except changes in material composition and shape design optimization. In the dynamic strain aging(DSA) temperature regime of gray cast iron, micro-dimples with different dimple depth over diameter and surface area density are fabricated on the material surface by laser peening(LP) which is an LST method. Friction behavior and wear mechanism are investigated to evaluate the effects of surface texturing on the tribological performance of specimens under dry conditions. Through LP impacts assisted by DSA, the friction coefficients of the LPed specimens increase noticeably both at room temperature and elevated temperature in comparison to untreated specimens. Moreover, the coefficient of specimen with dimple depth over diameter of 0.03 and surface area density of 30% is up to 0.351 at room temperature, which dramatically rises up to 1.33 times that of untextured specimen and the value is still up to 0.3305 at 400℃ with an increasing ratio of 35% compared to that of untreated specimen. The surface of textured specimen shows better wear resistance compared to untreated specimen. Wear mechanism includes adhesive wear, abrasive wear and oxidation wear. It is demonstrated that LP assisted by DSA can substantially improve wear resistance, raise the friction coefficient as well as its stability of gray cast iron under elevated temperatures. Heat fade and premature wear can be effectively relieved by this surface modification method. 展开更多
关键词 laser peening micro-dimples dynamic strain aging friction coefficient
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EFFECT OF DYNAMIC STRAIN AGING ON LOW CYCLE FATIGUE BEHAVIOUR OF 18-8 AUSTENITIC STAINLESS STEEL 被引量:2
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作者 PENG Kaiping CHEN Wenzhe OIAN Kuangwu Fuzhou University,Fuzhou,China teaching assistant,Department of Mechanical Engineering,Fuzhou University,Fuzhou 350002,China 《Acta Metallurgica Sinica(English Letters)》 SCIE EI CAS CSCD 1993年第6期420-425,共6页
Studies were made of the symmetric tensile-compressive low cycle fatigue behaviour and the influence of dynamic strain aging(DSA)pre-treatment of 18-8 austenitic stainless steel. Within the testing amplitude range of ... Studies were made of the symmetric tensile-compressive low cycle fatigue behaviour and the influence of dynamic strain aging(DSA)pre-treatment of 18-8 austenitic stainless steel. Within the testing amplitude range of strain.±0.5 % to±1.5 %,the three processes of cyclic hardening,cyclic saturation and cyclic softening were observed.In the same amplitude of strain,the peak stress of the samples pre-treated by DSA is higher than that of solid-solu- tion and cold working pre-treatment,but no remarkable differences of the fatigue lives of them were found.TEM observation shows that the uniform and stable dislocation networks with high density form after DSA pre-treatment,which increases the cyclic peak stress.The cyclic softening results from the low dislocation density and elongated cell structure with low energy. 展开更多
关键词 18-8 austenitic stainless steel dynamic strain aging low cycle fatigue
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Stress-state dependence of dynamic strain aging:Thermal hardening and blue brittleness 被引量:1
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作者 Wen-qi Liu Jun-he Lian 《International Journal of Minerals,Metallurgy and Materials》 SCIE EI CAS CSCD 2021年第5期854-866,共13页
This study aims to discover the stress-state dependence of the dynamic strain aging(DSA)effect on the deformation and fracture behavior of high-strength dual-phase(DP)steel at different deformation temperatures(25-400... This study aims to discover the stress-state dependence of the dynamic strain aging(DSA)effect on the deformation and fracture behavior of high-strength dual-phase(DP)steel at different deformation temperatures(25-400°C)and reveal the damage mechanisms under these various configurations.To achieve different stress states,predesigned specimens with different geometric features were used.Scanning electron microscopy was applied to analyze the fracture modes(e.g.,dimple or shear mode)and underlying damage mechanism of the investigated material.DSA is present in this DP steel,showing the Portevin-Le Chatelier(PLC)effect with serrated flow behavior,thermal hardening,and blue brittleness phenomena.Results show that the stress state contributes distinctly to the DSA effect in terms of the magnitude of thermal hardening and the pattern of blue brittleness.Either low stress triaxiality or Lode angle parameter promotes DSA-induced blue brittleness.Accordingly,the damage mechanisms also show dependence on the stress states in conjunction with the DSA effect. 展开更多
关键词 dynamic strain aging effect Portevin-Le Chatelier effect damage mechanism dimple fracture shear fracture dual-phase steel
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A DISLOCATION-MECHANICS-BASED CONSTITUTIVE MODEL FOR DYNAMIC STRAIN AGING 被引量:1
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作者 Guo Yangbo Tang Zhiping Cheng Jingyi 《Acta Mechanica Solida Sinica》 SCIE EI 2002年第2期119-126,共8页
Dynamic strain aging (DSA) is an important phenomenon in solutehardened metals and seri- ously affects the mechanical properties ofmetals. DSA is generally induced by the interaction between themoving dislocations and... Dynamic strain aging (DSA) is an important phenomenon in solutehardened metals and seri- ously affects the mechanical properties ofmetals. DSA is generally induced by the interaction between themoving dislocations and the mobile solute atoms. In this paper, onlythe interaction between moving disloca- tions and mobile solute atomsin a dislocation core area (core atmosphere) will be taken intoaccount. To es- tablish the constitutive model which can describe theDSA phenomenon, we improved the Zerilli-Armstrongdislocation-mechanics-based thermal viscoplastic constitutiverelation, and added the effect of the interaction between the movingdislocations and core atmosphere. 展开更多
关键词 dynamic strain aging solute atoms core atmosphere TANTALUM
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DYNAMIC STRAIN AGING BEHAVIOR OF K40S ALLOY
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作者 F.M. Yang, X.F. Sun, H.R. Guan and Z.Q. HuInstitute of Metal Research, The Chinese Academy of Sciences, Shenyang 110016, China 《Acta Metallurgica Sinica(English Letters)》 SCIE EI CAS CSCD 2003年第6期473-477,共5页
The dynamic strain aging behavior during tensile tests of K40S alloy has been investigated in the temperature range of 25-1100℃ with the strain rate range from 10-4 to 10-3s-1. The results show that four different ty... The dynamic strain aging behavior during tensile tests of K40S alloy has been investigated in the temperature range of 25-1100℃ with the strain rate range from 10-4 to 10-3s-1. The results show that four different types of serration, identified as A, B, C and E type serration were observed in the temperature range of 300-600℃. The strain exponents for onset of the serrated flow were calculated as 1.21, 2.19 and 1.61, and the activation energies as 121, 40 and 67kJ/mol for E, B and C type serration respectively. The main mechanism for dynamic strain aging discussed in light of the strain exponent and the activation energy. 展开更多
关键词 dynamic strain aging serrated flow strain exponent activation energy
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EFFECT OF DYNAMIC STRAIN AGING ON PURE BENDING FATIGUE STRENGTH OF AUSTENITIC STAINLESS STEEL
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作者 CHEN Wenzhe QIAN Kuangwu FuZhou University,Fuzhou,Fujian,China Lecturer,Dept.of Mechanical Engineering,Fuzhou University,Fuzhou,Fujian,China 《Acta Metallurgica Sinica(English Letters)》 SCIE EI CAS CSCD 1989年第5期359-363,共5页
The effect of various dynamic strain aging(DSA)pre-treatment processes on pure bending fatigue strength of an 18-8 austenitic stainless steel was investigated.The results show that DSA pre-treatment processes increase... The effect of various dynamic strain aging(DSA)pre-treatment processes on pure bending fatigue strength of an 18-8 austenitic stainless steel was investigated.The results show that DSA pre-treatment processes increase remarkably the fatigue strength and the strengthening effects increase with increasing pre-strain temperature and pre-strain.The fatigue limit of specimens pre-treated by DSA is 87% higher than that by solution treatment,and 20% high- er than that by cold-working.TEM observations show that the uniform and stable dislocation networks with high density formed after DSA pre-treatment,which suppress effectively the initiation and propugation of fatigue cracks and increase the fatigue strength of materials. 展开更多
关键词 dynamic strain aging(DSA) austenitic stainless steel fatigue strength
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Accuracy comparison and improvement for state of health estimation of lithium-ion battery based on random partial recharges and feature engineering
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作者 Xingjun Li Dan Yu +1 位作者 Søren Byg Vilsen Daniel Ioan Stroe 《Journal of Energy Chemistry》 SCIE EI CAS CSCD 2024年第5期591-604,共14页
State of health(SOH)estimation of e-mobilities operated in real and dynamic conditions is essential and challenging.Most of existing estimations are based on a fixed constant current charging and discharging aging pro... State of health(SOH)estimation of e-mobilities operated in real and dynamic conditions is essential and challenging.Most of existing estimations are based on a fixed constant current charging and discharging aging profiles,which overlooked the fact that the charging and discharging profiles are random and not complete in real application.This work investigates the influence of feature engineering on the accuracy of different machine learning(ML)-based SOH estimations acting on different recharging sub-profiles where a realistic battery mission profile is considered.Fifteen features were extracted from the battery partial recharging profiles,considering different factors such as starting voltage values,charge amount,and charging sliding windows.Then,features were selected based on a feature selection pipeline consisting of filtering and supervised ML-based subset selection.Multiple linear regression(MLR),Gaussian process regression(GPR),and support vector regression(SVR)were applied to estimate SOH,and root mean square error(RMSE)was used to evaluate and compare the estimation performance.The results showed that the feature selection pipeline can improve SOH estimation accuracy by 55.05%,2.57%,and 2.82%for MLR,GPR and SVR respectively.It was demonstrated that the estimation based on partial charging profiles with lower starting voltage,large charge,and large sliding window size is more likely to achieve higher accuracy.This work hopes to give some insights into the supervised ML-based feature engineering acting on random partial recharges on SOH estimation performance and tries to fill the gap of effective SOH estimation between theoretical study and real dynamic application. 展开更多
关键词 Feature engineering dynamic forklift aging profile State of health comparison Machine learning Lithium-ion batteries
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Study on the Deformation Behavior of Mg-3.6%Er Magnesium Alloy 被引量:5
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作者 王忠军 贾维平 崔建忠 《Journal of Rare Earths》 SCIE EI CAS CSCD 2007年第6期744-748,共5页
The deformation behaviour of a casting Mg-3.6% Er magnesium alloy after T6 treatment was studied in tensile tests from room temperature to 450 ℃ under different strain rates ranging from 1.0 ×10^-4 to 6.0 ×... The deformation behaviour of a casting Mg-3.6% Er magnesium alloy after T6 treatment was studied in tensile tests from room temperature to 450 ℃ under different strain rates ranging from 1.0 ×10^-4 to 6.0 × 10^-3 S^-1 Obtained local plateau in the temperature dependence of the ultimate strength (σb) and yield strength (σ0.2) under constant strain rate indicated the presence of dynamic strain ageing (DSA). Serrated flow was observed at the temperature of 200, 250, and 300 ℃. The observed negative strain rate sensitivity suggested that the serrated flow behavior arose from DSA. The temperature and strain rate dependence of the critical strain for the onset of serrated flow was analyzed using a phenomenological DSA equation, and the apparent activation energy Q for the serrated flow was obtained by calculation. 展开更多
关键词 Mg-3.6% Er alloy deformation behavior serrated flow dynamic strain aging rare earths
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Influence of solute cloud and precipitates on spatiotemporal characteristics of Portevin-Le Chatelier effect in A2024 aluminum alloys 被引量:4
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作者 孙亮 张青川 曹鹏涛 《Chinese Physics B》 SCIE EI CAS CSCD 2009年第8期3500-3507,共8页
In this paper, solute concentration and precipitate content in A2024 aluminum alloy are adjusted by solution treatment (ST) at different temperatures and tensile experiments on these treated specimens are carried ou... In this paper, solute concentration and precipitate content in A2024 aluminum alloy are adjusted by solution treatment (ST) at different temperatures and tensile experiments on these treated specimens are carried out. It is found that the temperature of solution treatment (ST temperature) has a remarkable influence on the amplitude of the serrated flow and the propagation characteristics of shear bands. These results are due to the effects of solute atoms and precipitates on dynamic strain aging (DSA). When ST temperature is higher than 300 ℃, solute concentration is relatively high and solute cloud is a key factor of DSA. When ST temperature is lower than 300 ℃, precipitate content is relatively high and the mechanism of DSA is determined by precipitates. 展开更多
关键词 aluminum alloy Portevin-Le Chatelier effect dynamic strain aging solution treatment precipitate particle
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Deformation measurements of three types of Portevin-Le Chatelier bands 被引量:4
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作者 项国富 张青川 +2 位作者 刘颢文 江慧丰 伍小平 《Chinese Physics B》 SCIE EI CAS CSCD 2006年第10期2378-2384,共7页
In this paper a technique based on high-speed digital photography and the digital speckle correlation (DSC) method is used for the quantitative measurement of the displacement and strain fields of various Portevin L... In this paper a technique based on high-speed digital photography and the digital speckle correlation (DSC) method is used for the quantitative measurement of the displacement and strain fields of various Portevin Le Chatelier (PLC) bands (types A, B, and C). The experimental results clearly show the nucleation process of a type-B band and the propagation of a type-A band. The results also reveal that there exists an elastic shrinkage deformation outside a PLC band during a large avalanche-like deformation inside the PLC band. 展开更多
关键词 Portevin-Le Chatelier (PLC) effect digital speckle correlation (DSC) method shear band dynamic strain aging (DSA)
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Effect of solute concentration on the serrated flow in solution-treated Al-4%Cu alloys 被引量:3
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作者 江慧丰 张青川 +1 位作者 孙亮 伍小平 《Chinese Physics B》 SCIE EI CAS CSCD 2006年第5期1051-1054,共4页
In order to compare with annealed Al-4%Cu alloys, the influence of solute concentration on the serrated flow is investigated by solution treatment. In this paper, some dynamic parameters, such as critical time and the... In order to compare with annealed Al-4%Cu alloys, the influence of solute concentration on the serrated flow is investigated by solution treatment. In this paper, some dynamic parameters, such as critical time and the ultimate tensile strength are obtained. Moreover, the change of the strain rate range for serrated flow in Al-4%Cu alloys prepared by annealing and quenching heat treatments is reported too. The difference between them is attributed to the increasing solute concentration in the bulk of the solution treated materials. 展开更多
关键词 Portevin-Le Chatelier effect solution treatment dynamic strain aging
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Influence of precipitation on the Portevin-Le Chatelier effect in Al-Mg alloys 被引量:3
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作者 Qi Hu,~(a))Qingchuan Zhang,~(b)) Shihua Fu,Pengtao Cao,and Ming Gong CAS Key Laboratory of Mechanical Behavior and Design of Materials,University of Science and Technology of China,Hefei 230027,China 《Theoretical & Applied Mechanics Letters》 CAS 2011年第1期30-33,共4页
In the alloy with solute content higher than the limiting solubility,the solute atoms that have failed to dissolve will precipitate from the solid solution and form precipitations.In this study, the Portevin-Le Chatel... In the alloy with solute content higher than the limiting solubility,the solute atoms that have failed to dissolve will precipitate from the solid solution and form precipitations.In this study, the Portevin-Le Chatelier(PLC) effects in annealed 5456 and 5052 aluminum alloys with different precipitation contents have been investigated under different applied strain rates.The results suggest that precipitations have significant effect on the PLC effect and the more the precipitations are, the greater the influence is.Furthermore,the solute diffusion is pipe diffusion in 5052 alloy with lower precipitation content.However,for 5456 alloy with higher precipitation content,the diffusion is no longer the case but more complex. 展开更多
关键词 aluminum alloys Portevin-Le Chatelier effect dynamic strain aging tension test
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Fracture toughness and fracture behavior of SA508-Ⅲ steel at different temperatures 被引量:2
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作者 Jia-hua Liu Lei Wang +3 位作者 Yang Liu Xiu Song Jiong Luo Dan Yuan 《International Journal of Minerals,Metallurgy and Materials》 SCIE EI CAS CSCD 2014年第12期1187-1195,共9页
The fracture toughness of SA508-Ⅲ steel was studied in the temperature range from room temperature to 320℃ using the J-integral method. The fracture behavior of the steel was also investigated. It was found that the... The fracture toughness of SA508-Ⅲ steel was studied in the temperature range from room temperature to 320℃ using the J-integral method. The fracture behavior of the steel was also investigated. It was found that the conditional fracture toughness (JQ) of the steel first decreased and then increased with increasing test temperature. The maximum and minimum values of do were 517.4 kJ/m^2 at 25℃ and 304.5 kJ/m^2 at 180℃, respectively. Dynamic strain aging (DSA) was also observed to occur when the temperature exceeded 260℃ with a certain strain rate. Both the dislocation density and the number of small dislocation cells effectively increased because of the occurrence of DSA; as a consequence, crack propagation was more strongly inhibited in the steel. Simultaneously, an increasing number of fine carbides precipitated under high stress at temperatures greater than 260℃. Thus, the deformation resistance of the steel was improved and the Jo was enhanced. 展开更多
关键词 low alloyed steel fracture toughness fracture behavior TEMPERATURE dynamic strain aging nuclear power plants
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A New Strategy for Restraining Dynamic Strain Aging in GH4169 Alloy During Tensile Deformation at High Temperature 被引量:2
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作者 Xin-Tong Lian Jin-Lan An +1 位作者 Lei Wang Han Dong 《Acta Metallurgica Sinica(English Letters)》 SCIE EI CAS CSCD 2022年第11期1895-1902,共8页
The dynamic strain aging(DSA) behavior was investigated in GH4169 alloy during tensile deforming with electric-pulse current(EPC) at 750 ℃.The results show that DSA is restrained in the alloy when deformed with 40 Hz... The dynamic strain aging(DSA) behavior was investigated in GH4169 alloy during tensile deforming with electric-pulse current(EPC) at 750 ℃.The results show that DSA is restrained in the alloy when deformed with 40 Hz-EPC.The size ofγ " phase inner grains increases obviously and δ phase is facilitated to precipitate on grain boundary in the alloy applied with EPC,due to the promotion effect of EPC on the diffusion and segregation of atoms.Transmission electron microscopy(TEM)results indicate that dislocations can cut through small γ" precipitate with the size of less than 10 nm,while dislocations can only bypass dislocations when γ " precipitate grow up over 20 nm.The growth of precipitates consumes large amounts of atoms as well as the velocity of dislocation increase,which makes dislocations difficult to be pinned.Therefore,when γ" precipitates grow up to a large size more than the critical size of dislocation pinning,DSA is significantly restrained in the alloy after necking deformed with EPC. 展开更多
关键词 GH4169 alloy Electric-pulse current dynamic strain aging MICROSTRUCTURE
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A critical review on the Portevin-Le Chatelier effect in aluminum alloys 被引量:1
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作者 ZHANG Peng LIU Gang SUN Jun 《Journal of Central South University》 SCIE EI CAS CSCD 2022年第3期744-766,共23页
The plastic deformation showing instability has been a subject receiving considerable attention for centuries due to its importance in many industrial processes.For Al alloys,the major instability is the Portevin-Le C... The plastic deformation showing instability has been a subject receiving considerable attention for centuries due to its importance in many industrial processes.For Al alloys,the major instability is the Portevin-Le Chatelier(PLC)effect that appears within a certain region of strain,strain rate and temperature.It manifests itself on the stress−strain curve as serrations associating with the rapid accumulation of plastic deformation within inclined slip bands.The PLC effect has severe practical consequences,which damages the surface quality after the sheet metal forming process and threatens the tensile ductility.Therefore,it is crucial to investigate the fundamental mechanisms underlying the PLC effect and in particular to investigate how it can be tempered by tailoring the material microstructure.In this paper,we review the common interpretations of the PLC effect and summarize the experimental results of the effects of the precipitation and the grain refinement,two conventional strengthening methodologies in Al alloys,on the serrated plastic flow.The effectiveness of solute atom clusters in suppressing the PLC effect is emphasized. 展开更多
关键词 Portevin-Le Chatelier effect dynamic strain aging PRECIPITATE grain size aluminum alloys
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Dynamic and Static Aging Precipitation of β-Mg_(17)Al_(12) in the AZ80 Magnesium Alloy During Multi-directional Forging and Subsequent Aging 被引量:1
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作者 Qing-Feng Zhu Gao-Song Wang +3 位作者 En-Ge Zhang Fan-Zheng Liu Zhi-Qiang Zhang Jian-Zhong Cui 《Acta Metallurgica Sinica(English Letters)》 SCIE EI CAS CSCD 2017年第10期941-948,共8页
Dynamic and static aging precipitation of Mg17Al12 phases in AZ80 magnesium alloy was studied by multidirectional forging(MDF) with decreasing temperatures from 410 to 300 ℃ and subsequent aging process. The result... Dynamic and static aging precipitation of Mg17Al12 phases in AZ80 magnesium alloy was studied by multidirectional forging(MDF) with decreasing temperatures from 410 to 300 ℃ and subsequent aging process. The results show that the morphology of the β-Mg17Al12 phases during forging process dynamically precipitates and aging process(statically precipitation) exhibited granular and laminar shapes, respectively. During the MDF, the inhomogeneous dynamic precipitation of the β-Mg17Al12 phases results in the uniformity on grain size, which is fine in the area with many granular Mg17Al12 phases but the grain is still coarse where there is no Mg17Al12 phases. During the aging process, the morphology of newly formed β-Mg17Al12 phases depends on the structural character of the forged sample. The newly precipitated β-Mg17Al12 phases are coarse laminar and needle-like shape in area with coarse grain. While, the fine newly precipitated β-Mg17Al12 phases are fine granular and needle-like in the area with fine grain. 展开更多
关键词 dynamic strain aging PRECIPITATION AZ80 magnesium alloy Multi-directional forging dynamic recrystallization
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Effect of strain rate and temperature on the serration behavior of SA508-Ⅲ RPV steel in the dynamic strain aging process 被引量:1
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作者 Xue Bai Su-jun Wu +3 位作者 Li-jun Wei Shuai Luo Xie Xie Peter K. Liaw 《Journal of Iron and Steel Research International》 SCIE EI CAS CSCD 2018年第7期767-775,共9页
Dynamic strain aging (DSA) effect on SA508-III reactor pressure vessel (RPV) steel was investigated. The SA508-III RPV steel was subjected to tension tests at different strain rates (1.1× 10-5 s-1 and 6.6... Dynamic strain aging (DSA) effect on SA508-III reactor pressure vessel (RPV) steel was investigated. The SA508-III RPV steel was subjected to tension tests at different strain rates (1.1× 10-5 s-1 and 6.6× 10-5 s-1) and different temperatures (500 and 550 ℃) to evaluate the influence of strain rate and temperature on the serrated flow behavior, which is the repetitive and discontinuous yielding phenomenon on the stress-strain curves. The higher temperature leads to the higher density of precipitates, M23C6 carbides and needle-like Mo2C carbides. It was found that the samples under tension test of 6.6 × 10-5 s-1 and 500 ℃ possess superior mechanical properties and mainly show A-type serrations on the tension test curves. Then, the local regress method was used to filter the DSA curves, thus to show the real trend of the curves. It has been found that the less time of interaction between dislocations and precipitates under higher strain rates leads to a higher strength of the sample. The more tiny-stress drops on the 550 ℃ serration curve can be attributed to the hardening phase, M23C6 carbides and needle-like Mo2C carbides. The higher percentage of the small stress drops on the serration curves represents the higher mechanical strength. 展开更多
关键词 Reactor pressure vessel steel SA508-Ⅲ steel dynamic strain aging Serration behavior
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Complexity analysis of the Portevin-Le Chatelier in an Al alloy atdifferent tem peratures 被引量:1
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作者 Jianfei Xu Guoxiong Chen Shihua Fu 《Theoretical & Applied Mechanics Letters》 CSCD 2021年第2期81-84,共4页
The complexity of the Portevin-Le Chatelier(PLC)effect in an Al alloy at different temperatures was ana-lyzed by modified multiscale entropy.The results show that three evolutions of entropy with scale factor,i.e.,nea... The complexity of the Portevin-Le Chatelier(PLC)effect in an Al alloy at different temperatures was ana-lyzed by modified multiscale entropy.The results show that three evolutions of entropy with scale factor,i.e.,near zero,monotonically increasing and peak-shape,were observed corresponding to the smoothcurves,type-A serrations and type-B/-C serrations,respectively.The scale factor at the peak was one-third of the average serration period.The sample entropy increased initially and then decreased withtemperature,which was opposite to the critical strain.It is also suggested that the type-A serrations cor-responded to self-organized criticality and the type-B/-C serrations corresponded to chaos through theevolutions of entropy with scale factor. 展开更多
关键词 Portevin-Le Chatelier effect dynamic strain aging COMPLEXITY Modified multiscale entropy
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Strain Hardening Associated with Dislocation,Deformation Twinning,and Dynamic Strain Aging in Fe–20Mn–1.3C–(3Cu) TWIP Steels 被引量:2
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作者 Lingyan Zhao Dingyi Zhu +2 位作者 Longlong Liu Zhenming Hu Mingjie Wang 《Acta Metallurgica Sinica(English Letters)》 SCIE EI CAS CSCD 2014年第4期601-608,共8页
The effects of Cu on stacking fault energy,dislocation slip,mechanical twinning,and strain hardening in Fe–20Mn–1.3C twinning-induced plasticity(TWIP) steels were systematically investigated.The stacking fault ene... The effects of Cu on stacking fault energy,dislocation slip,mechanical twinning,and strain hardening in Fe–20Mn–1.3C twinning-induced plasticity(TWIP) steels were systematically investigated.The stacking fault energy was raised with an average slope of 2 mJ/m2 per 1 wt% Cu.The Fe–20Mn–1.3C–3Cu steel exhibited superior tensile properties,with the ultimate tensile strength reached at 2.27 GPa and elongation up to 96.9% owing to the high strain hardening that occurred.To examine the mechanism of this high strain hardening,dislocation density determination by XRD was calculated.The dislocation density increased with the increasing strain,and the addition of Cu resulted in a decrease in the dislocation density.A comparison of the strain-hardening behavior of Fe–20Mn–1.3C and Fe–20Mn–1.3C–3Cu TWIP steels was made in terms of modified Crussard–Jaoul(C–J) analysis and microstructural observations.Especially at low strains,the contributions of all the relevant deformation mechanisms—slip,twinning,and dynamic strain aging—were quantitatively evaluated.The analysis revealed that the dislocation storage was the leading factor to the increase of the strain hardening,while dynamic strain aging was a minor contributor to strain hardening.Twinning,which interacted with the matrix,acted as an effective barrier to dislocation motion. 展开更多
关键词 Twinning-induced plasticity(TWIP) Strain hardening Mechanical twinning Dislocation density dynamic strain aging
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