检索结果-南通市图书馆

Cellular automaton modeling of austenite formation from ferrite plus pearlite microstructures during intercritical annealing of a C-Mn steel

在线全文

学校读者我要写书评

暂无评论

Journal of Materials Science & Technology 2020年第12期47卷 1-9页

作者： Chunni Jia Chengwu Zheng dianzhong li Shenyang National Laboratory for Materials Science Institute of Metal ResearchChinese Academy of Sciences.Shenyang110016China School of Materials Science and Engineering University of Science and Technology of ChinaShenyang110016China

A mesoscopic cellular automaton model was developed to study the microstructure evolution and solute redistribution of austenization during intercritical annealing of a C-Mn steel. This model enables a depiction of three-stage kinetics of the transformation combined with the thermodynamic analysis:(1) the rapid austenite growth accompanied with pearlite degeneration until the pearlite dissolves completely;(2) the slower austenite growth into ferrite with a rate limiting factor of carbon diffusion in austenite;and(3) the slow austenite growth in control of the manganese diffusion until the final equilibrium reached for ferrite and austenite. The effect of the annealing temperature on the transformation kinetics and solute partition is also quantitatively rationalized using this model.

关键词： Austenization Intercritical annealing C-Mn steels Cellular automaton Mesoscale modeling

克氏原螯虾三群体双列杂交组合生长性能和耐干露能力比较分析

在线全文

学校读者我要写书评

暂无评论

上海海洋大学学报 2024年第2期33卷 361-370页

作者：邹宇凡吴玮杰白志毅李典中蒋军程熙李家乐上海海洋大学农业农村部淡水水产种质资源重点实验室上海201306 上海海洋大学上海市水产动物良种创制与绿色养殖协同创新中心上海201306 安徽省水产技术推广总站安徽合肥230000 芜湖盛典休闲生态园有限公司安徽芜湖241212 上海市嘉定区水产技术推广站上海201800

以遗传多样性高、生长快的江苏滆湖、江苏建湖和安徽芜湖3个克氏原螯虾优异种质群体进行双列杂交试验,得到6个杂交组[滆湖♀×建湖♂(GJ)、建湖♀×滆湖♂(JG)、滆湖♀×芜湖♂(GW)、芜湖♀×滆湖♂(WG)、建湖♀×芜湖♂(JW)、芜湖♀×... 详细信息

以遗传多样性高、生长快的江苏滆湖、江苏建湖和安徽芜湖3个克氏原螯虾优异种质群体进行双列杂交试验,得到6个杂交组[滆湖♀×建湖♂(GJ)、建湖♀×滆湖♂(JG)、滆湖♀×芜湖♂(GW)、芜湖♀×滆湖♂(WG)、建湖♀×芜湖♂(JW)、芜湖♀×建湖♂(WJ)]和3个自交组[滆湖♀×滆湖♂(GG)、建湖♀×建湖♂(JJ)、芜湖♀×芜湖♂(WW)],对9个组合生长性能和生态适应性比较分析,结果表明:(1)养殖周期内,WW和JJ组合雌雄个体体质量特定增长率、增重率均显著大于其余组合;除GJ和JG外其余组合雄性个体体质量特定增长率、增重率显著大于雌性,3—5月各杂交组生长性状均未见杂种优势;(2)随养殖时间的增加,9个群体克氏原螯虾头胸甲长/体长、腹部长/体长变化明显,头胸甲长/体长逐渐增加,腹部长/体长逐渐减小且5月雌雄个体间出现分化,雌性腹部长占比显著大于雄性。头胸甲宽/体长、腹部宽/体长、尾节长/体长仅4月有明显增加;(3)干露24 h各组虾开始出现死亡,48 h各组存活率出现显著分化,48 h时WW组合存活率显著大于其余组合,GJ和JG两个正反交组在耐干露能力方面呈现出杂种优势。本研究发现克氏原螯虾种质混杂一定程度限制了生长性状杂种优势,但抗逆性表现出杂种优势,适当杂交再选育是重要的育种策略,克氏原螯虾生长和腹部长占比呈明显雌雄二态性,单性育种也是重要方向。

关键词：克氏原螯虾群体间杂交生长性能干露胁迫杂种优势

High-temperature Tensile Behavior in Coarse-grained and Fine-grained Nb-containing 25Cr-20Ni Austenitic Stainless Steel

在线全文

学校读者我要写书评

暂无评论

Acta Metallurgica Sinica(English Letters) 2020年第11期33卷 1455-1465页

作者： Guodong Hu Pei Wan dianzhong li Yiyi li Shenyang National Laboratory for Materials Science Institute of Metal ResearchChinese Academy of Sciences72 Wenhua Road.Shenyang 110016China School of Materials Science and Engineering Universityof Science and Technology of China72 Wenhua RoadShenyang 110016China Centre of Excellence for Advanced Materials Dongguan 523808China Songshan Lake Laboratory for Materials Science Dongguan 523808China

In this study,tensile behavior of Nb-containing 25Cr-20Ni austenitic stainless steels composed of coarse or fine grains has been investigated at temperatures ranging from room temperature to 900℃.Results show that the tensile strength of fine-grained specimens decreases faster than that of coarse-grained specimens,as the test temperature increases from 600℃ to 800℃.The rapidly decreasing tensile strength is attributed to the enhanced dynamic recovery and recrystallization,because additional slip systems are activated,and cross-slipping is accelerated during deformation in fine-grained *** tensile testing at 700-900℃,sigma phases are formed concurrently with dynamic recrystallization in fine-grained *** precipitation of sigma phases is induced by simultaneous recrystallization as the diffusion of alloying elements is accelerated during the recrystallization ***,the minimum ductility is observed in coarse-grained specimens at 800℃,which is caused by the formation of M23C6 precipitates at the grain boundaries.

关键词： Austenitic stainless steels High-temperature tensile properties Grain size Precipitates

Role of Solute Rare Earth in Altering Phase Transformations during Continuous Cooling of a Low Alloy Cr–Mo–V Steel

在线全文

学校读者我要写书评

暂无评论

金属学报:英文版 2023年第9期36卷 1523-1535页

作者： Zhonghua Jiang Pei Wang dianzhong li Shenyang National Laboratory for Materials Science Institute of Metal ResearchChinese Academy of SciencesShenyang110016China

Effects of solute rare earth(RE)on continuous cooling transformation of a low-alloy Cr–Mo–V bainitic steel are investigated in detail by dilatometry,optical microscopy(OM),scanning electron microscopy(SEM)and transmission electron microscopy(TEM).Microstructures appeared in thermal dilatometric samples of both low-alloy Cr–Mo–V(RE)steels are composed of quasi-polygonal ferrite(QPF),degenerate pearlite(DP),granular bainite(GB),lath bainite(LB),and martensite(M)depending on cooling *** cooling rate is lower than 2°C/s,the addition of RE suppresses QPF transformation,and thereby inducing a broader transformation region of *** cooling rate ranges from 2 to 100°C/s,the addition of RE decreases the start temperature of bainitic transformation distinctly,which results in finer bainitic ferrite grain size and higher dislocation *** addition of RE can enhance the hardness of the low alloy Cr–Mo–V steel by affecting the aforementioned diffusional and/or partly displacive ***,when cooling rate increases up to 150°C/s,two steels have the same hardness value of about 435 HV due to only martensite obtained by displacive transformation.

关键词： Low-alloy Cr-Mo-V steel Rare earth Phase transformation Bainitic microstructures Continuous cooling transformation

Effect of aging treatment on the microstructures and mechanical properties evolution of 25Cr-20Ni austenitic stainless steel weldments with different Nb contents

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Journal of Materials Science & Technology 2019年第4期35卷 520-529页

作者： Xu Zhang dianzhong li Yiyi li Shanping Lu Key Laboratory of Nuclear Materials and Safety Assessment Institute of Metal ResearchChinese Academy of Sciences School of Materials Science and Engineering University of Science and Technology of China Shenyang National Laboratory for Materials Science Institute of Metal ResearchChinese Academy of Sciences

The microstructure evolutions and the mechanical properties of the 25Cr-20Ni austenitic stainless steel weld metals with different Nb contents were investigated during the long term aging treatment at 700~?C.M_(23)C_6,Nb(C,N),α-Cr phase and Nb-nitride phase(Z phase)were observed in the microstructures of the aged weld *** results showed that theα-Cr phase precipitated in the interdendritic regions of the weld metals after being exposed to~ 700?C for 500 h and the element Nb accelerated the precipitation of theα-Cr phase *** density of theα-Cr phase decreased with the increase of the distance away from the primary Nb(C,N).Additionally,theα-Cr phase showed a crystallographic relationship with the austenitic matrix,■.It was observed that the Z phase precipitated in the periphery of the Nb(C,N)and may replace the Nb(C,N)after long term exposure to high *** transformation of the Nb(C,N)into Z phase suggested that the Z phase had a higher stability than the Nb(C,N)par^ticles at 700?C for long term *** tensile strength of the Nb-bearing weld metal showed a continuous decrease at the initial stage of the aging treatment and then went up slightly with the prolonged aging ***,the elongations and the impact energies of the weld metals decreased monotonously with the increase of the aging time.

关键词： 25Cr-20Ni steel Weld metal Nb Aging treatment α-Cr phase Mechanical property

Effect of Structural Parameters of Double Shielded TIG Torch on the Fusion Zone Profile for 0Cr13Ni5Mo Martensitic Stainless Steel

在线全文

学校读者我要写书评

暂无评论

Journal of Materials Science & Technology 2014年第9期30卷 922-927页

作者： Dongjie li Shanping Lu dianzhong li Yiyi li Shenyang National Laboratory for Materials Science Institute of Metal Research Chinese Academy of Sciences

The effects of double shielded TIG （tungsten inert gas） torch＇s structural parameters, including the flow rate ratio between the inner and outer layers of gas and the extended length of the electrode （abbreviated as ELE in this work）, on the fusion zone profile have been investigated for OCrl3NiSMo martensitic stainless steel. Results show that the double shielded TIG process yields relatively high penetration of the weld pool in a broad range of the structural parameters. ELE over 3 mm is too large and causes adverse reactions on the protection of electrode. The outer gas with relatively high flow rate or the outer layer with high oxygen content is conducive to the oxygen dissolved into the arc, which results in the oxidation of the weld pool surface and the electrode tip. The double shielded TIG welded metal was tested and presented good impact property.

关键词： Structural parameters Flow rate Electrode extended length Impact energy

Modeling of Solidification Microstructures Based on Fully Coupling of Macro-transport Phenomena with Cellular Automata

在线全文

学校读者我要写书评

暂无评论

Journal of Materials Science & Technology 2000年第6期16卷 568-572页

作者： Qiang DU dianzhong li Yiyi li Institute of Metal Research Chinese Academy of SciencesShenyang 110015China

This paper has attempted to simulate the microstructure formation based on fully coupling of temperature field, concentration field and velocity field with micro-kinetics. The authors presented a new way, which is the combination of FDM and cellular automata (CAFD) to visualize the microstructure formation of the thin complex superalloy turbine blades cast by the vacuum investment process. The distribution, orientation and mechanism of the heterogeneous nucleation, the growth kinetics of dendrites and the columnar to equiaxed transition (CET) are considered. Capitalizing on these simulating schemes, the comprehensive influence of key process variables on the scale and uniformity of grains has been investigated quantitatively. The simulated grain size and morphology agree well with the experimental results.

关键词： Microstructure

Multi-scale study on the heterogeneous deformation behavior in duplex stainless steel

在线全文

学校读者我要写书评

暂无评论

Journal of Materials Science & Technology 2021年第13期72卷 180-188页

作者： Xiao Zhang Pei Wang dianzhong li Yiyi li Shenyang National Laboratory for Materials Science Institute of Metal ResearchChinese Academy of Sciences72 Wenhua RoadShenyang 110016China School of Materials Science and Engineering University of Science and Technology of ChinaShenyang 110016China

The heterogeneous deformation behavior of austenite and ferrite in the 2205 duplex stainless steel was subjected to multiscale analysis based on the in situ synchrotron-based high energy X-ray diffraction,microscopic digital image correlation,electron backscatter diffraction,and transmission electron *** is found that the heterogeneous deformation triggers from the yielding of *** this deformation stage,austenite experiences greater strain in the area near the phase boundaries because of the impeded function of the phase boundaries to *** to the relatively small difference in hardness between the constituent phases,the strain in austenite grains extends into the adjacent ferrite grains when entering into the ferrite yielding *** addition,the strain distribution of the austenite grains is more homogeneous than that of the ferrite grains because of the lower stacking fault energy of austenite,which results in a planar slip,and higher stacking fault energy in case of ferrite,causing cross *** interaction between austenite and ferrite becomes considerably obvious when the strain further increases after both constituent phases yielding because of the back stress and forward stress in austenite and ferrite,respectively,which are generated by the pile-up of the geometrically necessary dislocations.

关键词： Duplex stainless steel Heterogeneous deformation behavior Digital image correlation Back stress Geometrically necessary dislocation

Principles Giving High Penetration under the Double Shielded TIG Process

在线全文

学校读者我要写书评

暂无评论

Journal of Materials Science & Technology 2014年第2期30卷 172-178页

作者： Dongjie li Shanping Lu dianzhong li Yiyi li Shenyang National Laboratory for Materials Science Institute of Metal ResearchChinese Academy of Sciences

A new welding method named double shielded tungsten inert gas （TIG） has been developed to improve the TIG weld penetration. The main principles to increase the weld depth have been discussed. Results show that the critical oxygen content in the weld pool is around 100 × 10 -6 as the temperature coefficient of surface tension changes from negative to positive. The tracer test using pure silver shows that the direction of Marangoni convection changes as the oxygen content increases in the weld pool. The effect of arc constriction on the weld depth has been evaluated on a water-cooled copper plate, and the result indicates that the torch of double shielded can give a more powerful arc. Heavy oxide on the pool surface has undesirable impacts on the increasing of weld depth as the oxygen excessively accumulates in weld pool. It is possible to form chromium oxide in the weld process, while the iron oxide may form as the weld surface exposes to the air after the shielded gas moving away.

关键词： Marangoni convection Penetration Tungsten inert gas (TIG) Arc Oxide