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Spheroidization and Ostwald Growth of Carbide in Isothermal Process of Hot-Deformed High Carbon Chromium Cast Steel 被引量:7
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作者 CHANG Li-min LIU Jian-hua +1 位作者 WANG Hai-yan YU Sheng-xue 《Journal of Iron and Steel Research International》 SCIE EI CAS CSCD 2003年第1期36-39,共4页
In isothermal spheroidizing process,the spheroidization and growth of the carbide formed in hot-deformed high-carbon chromium cast steel at high temperature were investigated.The results showed that the spheroidizing ... In isothermal spheroidizing process,the spheroidization and growth of the carbide formed in hot-deformed high-carbon chromium cast steel at high temperature were investigated.The results showed that the spheroidizing growth of carbide proceeds in such a way that the bigger carbide particles swallow the smaller ones,and the short rhabdoid carbides dissolve and are spheroidized by itself.When the samples were held at 720℃ for more than 3 h,the spheroidization is not obvious.The feature of the process is the size increment and the amount decrement of carbide particles.The empirical equation for growth rate of carbides was obtained.The volume fraction of carbides keeps constant.The growth process agrees well with Ostwald Ripening Law. 展开更多
关键词 hot-deformed high-carbon chromium cast steel CARBIDE isothermal spheroidizing Ostwald Ripening Law
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MODELLING FOR PREDICTION OF CONTINUOUS COOLING TRANSFORMATION KINETICS OF HOT-DEFORMED AUSTENITE STEEL 被引量:1
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作者 J.B.Qu Z.D.Wang +1 位作者 X.H.Liu G.D.Wang 《Acta Metallurgica Sinica(English Letters)》 SCIE EI CAS CSCD 1998年第3期225-229,共5页
On the thermodynamics basis of regular solution sub-lattice model and soperelement model, kinetics basis of Cahn's transformation kinetics theory, and according to Scheil's additivity rule and eoperimental res... On the thermodynamics basis of regular solution sub-lattice model and soperelement model, kinetics basis of Cahn's transformation kinetics theory, and according to Scheil's additivity rule and eoperimental results obtained by thermal dilation method,a prediction model of transformations from hot-deformed austenite to ferrite, pearlite and bainite in low alloy steels, which could be applied to continuoas cooling process, is developed. The calculated transformed junctions of each phase based on laboratory controlled rolling and controlled cooling conditions in a low alloy steel are in reasonable agreement with the measured ones. 展开更多
关键词 transformation kinetics THERMODYNAMICS continuous cooling hot-deformed austenite
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MATHEMATICAL MODELLING OF PHASE TRANSFORMATION FROM HOT-DEFORMED AUSTENITE IN LOW CARBON STEELS
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作者 Y.B.Xu G.D.Wang X.H.Liu 《Acta Metallurgica Sinica(English Letters)》 SCIE EI CAS CSCD 2003年第3期204-210,共7页
On the basis of superelement model, Cahn’s transformation kinetics theory and Scheil’s additivity rule, the CCT diagrams and transformation kinetics in low carbon steel were predicted considering both undeformed and... On the basis of superelement model, Cahn’s transformation kinetics theory and Scheil’s additivity rule, the CCT diagrams and transformation kinetics in low carbon steel were predicted considering both undeformed and deformed conditions. The influence of deformation on phase equilibria and transformation incubation period was evaluated quantitatively. The recrystallization kinetics and the evolution of dislocation density were calculated during continuous cooling. The results show deformation considerably shortens transformation incubation period, accelerates transformation kinetics and makes CCT curve shift leftwards. The calculated CCT diagrams and the volume fraction of each phase are in good agreement with measurements. 展开更多
关键词 THERMODYNAMICS transformation kinetics continuous cooling hot-deformed austenite
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Deformation-induced α_2/γ Interfaces in a Hot-deformed Ti-45Al-10Nb Alloy
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作者 Jinguo WANG Lichun ZHANG and Guoliang CHEN (State Key Lab. for Advanced Metals and Materials, University of Science and Technology Beijing, Beijing 100083, China )Henqiang YE(Lab. of Atomic Imaging of Solids, Institute of Metal Research, Chinese Academy 《Journal of Materials Science & Technology》 SCIE EI CAS CSCD 1998年第2期132-138,共7页
The structure change of α2/γ interface in a Ti-45Al-10Nb alloy induced by hot deformation was investigated by conventional and high-resolution transmission eIectron microscopy. Two types of hot deformation induced s... The structure change of α2/γ interface in a Ti-45Al-10Nb alloy induced by hot deformation was investigated by conventional and high-resolution transmission eIectron microscopy. Two types of hot deformation induced special α2/γ intedeces, coherent intedeces with high density of ledges and semi-coherent α2/γ intedeces were found to be due to the absorption of mobile dislocations into the α2/γ inteface. For the misoriented semi-coherent α2/γ interfaces, the densities of dislocation ledges increase with the misoriented angle between (111)γ and (0001)α2 planes, and 1/3[111] Frank partial dislocations were involved in the dislocation ledges. Formation mechanism of these deformation-induced α2/γ interfaces was discussed to be related to the role of α2/γ interface5 adjusting the deformation as a dislocation sink absorbing the slipping dislocations in the γ phase 展开更多
关键词 Al TI Interfaces in a hot-deformed Ti-45Al-10Nb Alloy Deformation-induced
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Simultaneously enhancing coercivity and remanence of hot-deformed Nd-Fe-B magnets by flake copper powder assisted DyF_(3) interflake addition
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作者 Yikuan Hu Jiajie Li +5 位作者 Shengyu Sun Shuwei Zhong Munan Yang Xiaoqiang Yu Sajjad Ur Rehman Xi Yu 《Journal of Rare Earths》 SCIE EI CAS CSCD 2024年第7期1282-1288,I0003,共8页
It is still a challenge to simultaneously enhance coercivity(H_(cj))and remanence(J_(r))of hot-deformed Nd-Fe-B magnet due to the coercivity-remanence trade-off dilemma.Here,we achieved this balance between H_(cj)and ... It is still a challenge to simultaneously enhance coercivity(H_(cj))and remanence(J_(r))of hot-deformed Nd-Fe-B magnet due to the coercivity-remanence trade-off dilemma.Here,we achieved this balance between H_(cj)and Jr by flake Cu powder assisted DyF_(3)interflake addition.The Hcj increases from 1218 to 1496 kA/m and Jr increases from 1.32 to 1.34 T compared with the original magnet.Results show that the width of coarse grain layers reduces because of the introduction of flake Cu,which increases the contact areas of the adjacent grains at ribbon interfaces and suppresses the excessive growth of grains.The stronger degree of texture and higher density compared with the original magnet should take the responsibility for the increase of J_(r).Additionally,the aggregation regions of rare earth rich(RE-rich)phase reduce and the betterment of the microstructure is another reason for the enhancement of Jr in the flake Cu aided DyF_(3)hot-deformed magnet.This strategy of using flake powder additives provides a promising method for optimizing microstructure and enhancing magnetic properties of hot-deformed Nd-Fe-B magnets. 展开更多
关键词 Rare earths Nd-Fe-B hot-deformed magnet Flake powder Interflake addition REMANENCE
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Recent progress of grain boundary diffusion process for hot-deformed Nd-Fe-B magnets 被引量:2
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作者 Min Zhao Na Liu +8 位作者 Xu Tang Renjie Chen Jinyun Ju Wenzong Yin Yeyuan Du Aru Yan Xincai Liu Jing Pan Zhiyi Xu 《Journal of Rare Earths》 SCIE EI CAS CSCD 2023年第4期477-488,共12页
Grain boundary diffusion process(GBDP)was first proposed for sintered Nd-Fe-B magnets to achieve the high utilization efficiency of heavy rare earth elements.Recent success of fabricating high performance nanocomposit... Grain boundary diffusion process(GBDP)was first proposed for sintered Nd-Fe-B magnets to achieve the high utilization efficiency of heavy rare earth elements.Recent success of fabricating high performance nanocomposite magnets by GBDP indicates that this method also exerts huge applicable potential on hot-deformed Nd-Fe-B magnets.In this review,the development and magnetic property enhancement mechanisms of different diffusion methods proposed on hot-deformed magnets were thoroughly elucidated.Moreover,the improve room for further property enhancement and the accompanying problems of GBDP on hot-deformed magnets are also discussed in this article. 展开更多
关键词 hot-deformed Nd-Fe-B magnets Grain boundary diffusion process Magnetic properties Micromagnetic simulations Rare earths
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Coercivity enhancement of hot-deformed Nd-Fe-B magnets with Pr-Cu alloy addition
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作者 Jun-Ming Wang Zhao-Hui Guo +5 位作者 Zheng Jing Xiao Du Neng-Jun Yu Meng-Yu Li Ming-Gang Zhu Wei Li 《Rare Metals》 SCIE EI CAS CSCD 2023年第4期1403-1407,共5页
Effects of low-melting Pr-Cu alloy addition on the microstructure and magnetic properties of the hot-deformation Nd-Fe-B magnets were investigated.A small amount of Pr-Cu addition enhances the coercivity of the hot-de... Effects of low-melting Pr-Cu alloy addition on the microstructure and magnetic properties of the hot-deformation Nd-Fe-B magnets were investigated.A small amount of Pr-Cu addition enhances the coercivity of the hot-deformation Nd-Fe-B magnets obviously.The coercivity of the hotdeformation Nd-Fe-B magnets with 4.0 wt%Pr_(85)Cu_(15)addition increases to 1271 kA·m^(-1),75.69%higher than that of Pr-Cu-free magnet(723 kA·m^(-1)),and then decreases with5 wt%Pr_(85)Cu_(15)addition.It is observed that there a uniform RE-rich phase is formed wrapping the Nd2Fe14B main phase in the sample with 4.0%Pr_(85)Cu_(15)addition by scanning electron microscopy(SEM),which promotes the coercivity.The angular dependence of coercivity for the hot-deformation Nd-Fe-B magnets indicates that the coercivity mechanism is nucleation combined with domain wall pinning.The domain wall pinning is weakened,while the nucleation is enhanced after Pr-Cu addition.Theremanence,intrinsic coercivity,and maximum magnetic energy product of the original Nd-Fe-B magnet are 1.45 T,723 kA·m^(-1),and 419.8 kJ·m^(-3),respectively,and those of the sample with 4.0%Pr_(85)Cu_(15)alloy addition are 1.30 T,1271 kA·m^(-1),and 330.0 kJ·m^(-3),respectively. 展开更多
关键词 ND-FE-B Low-melting alloy hot-deformation Microstructure Coercivity mechanism
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Magnetic properties enhancement of hot-deformed NdFeB magnets by two different methods of CeNdCu diffusion 被引量:5
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作者 Guibing Shi Zilong Wang +3 位作者 Xinyuan Bai Wenlong Yan Yang Luo Dunbo Yu 《Journal of Rare Earths》 SCIE EI CAS CSCD 2020年第12期1312-1316,共5页
Two different ways were used to control the distribution of cerium for the enhancement of coercivity.One was by coating CeNdCu in the prepared magnet and annealing to make CeNdCu diffuse into the grain boundary to inc... Two different ways were used to control the distribution of cerium for the enhancement of coercivity.One was by coating CeNdCu in the prepared magnet and annealing to make CeNdCu diffuse into the grain boundary to increase the coercivity,the other was by mixing CeNdCu with initial magnetic powders and then preparing the hot-deformed magnet.The SEM-EDS result indicates that cerium diffuses more easily into the main phase by the mixing way,while cerium is mainly distributed in the grain boundary via the coating way.The heat-treatment process may be one of the dominant influencing factors for the distribution of Ce,Multi-steps heat treatment in the mixing way,consisting of hot-pressing,hot-deforming and post heat process,easily introduces Ce into the main phase Nd2 Fe14B,which forms the Ce2 Fe14B shell resulting in the decrease of HA.But the coating way can ensure uniform dispersion of Ce in the grain boundary,which leads to the high coercivity. 展开更多
关键词 hot-deformed magnet Coating MIXING CeNdCu Rare earths
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Microstructure and magnetic properties of anisotropic hot-deformed magnet of different magnetic particle sizes 被引量:5
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作者 Xu-Chao Wang Ming-Gang Zhu +3 位作者 Wei Li Yan-Feng Li Bin Lai An Du 《Rare Metals》 SCIE EI CAS CSCD 2015年第4期255-258,共4页
In this paper, the magnetic Nd-Fe-B particles of different sizes were conducted under vacuum by the hot pressing, then cooled quickly to room temperature. Finally hot deformation was performed to get the anisotropy Nd... In this paper, the magnetic Nd-Fe-B particles of different sizes were conducted under vacuum by the hot pressing, then cooled quickly to room temperature. Finally hot deformation was performed to get the anisotropy Nd-Fe- B magnet at a deformation rate of 70 % in the protection of argon atmosphere. NIM-2000 was used for the measurement of hysteresis loop of the samples. Meanwhile, scanning electron microscopy (SEM) was used to observe the surface morphology of the magnetic particles with different sizes and hot-deformed magnets, energy spectrum analyzer to analyze the composition of magnetic particles. The effect of magnetic particle sizes on the microstructure and magnetic properties of the hot-deformed anisotropic magnet was investigated. Anisotropic hot-deformed magnets produced from the maximum particle size of 200-350 μm have the highest magnetic properties of Br = 1.465 T, Hcj = 1,157 kA.m-1, (Bn)max = 425 kJ.m-3. 展开更多
关键词 Magnetic property hot-deformed magnet Magnetic particle SIZE
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Effect of heterogeneous microstructure on magnetization reversal mechanism of hot-deformed Nd-Fe-B magnets 被引量:3
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作者 Yuqing Li Xiaochang Xu +3 位作者 Ming Yue Dan Wu Weiqiang Liu Dongtao Zhang 《Journal of Rare Earths》 SCIE EI CAS CSCD 2019年第10期1088-1095,共8页
The hot-deformed(HD) Nd-Fe-B magnets show heterogeneous microstructure composed of coarse and fine grain regions. It is significant to fully understand the influence of this complex microstructure on the magnetization... The hot-deformed(HD) Nd-Fe-B magnets show heterogeneous microstructure composed of coarse and fine grain regions. It is significant to fully understand the influence of this complex microstructure on the magnetization reversal process which can give the guidance for the enhancement of the magnetic properties. In this paper, the heterogeneous microstructure of the(HD) Nd-Fe-B magnets were characterized from the morphology, size, macro-texture and micro-structure. In addition, the magnetization reversal process of the HD Nd-Fe-B magnets was systematically analyzed by magnetic measurement, insitu domain evolution observation and micromagnetic simulation. The results indicate that the HD NdFe-B magnets mainly consist of fine grain regions(FGRs) and coarse grain regions(CGRs). The FGRs show plate-like grains with fine grain size and strong c-axis texture, while the CGRs show equiaxial grains with large grain size and weak c-axis texture. In particular, it is worth noting that the texture in homogeneity exists not only between FGRs and CGRs, but also inside both the FGRs and CGRs. The dominant coercivity mechanism of the HD Nd-Fe-B magnets is domain wall pinning. Also, the experimental analysis shows that the reverse domain is formed and expanded in the CGRs at low reverse applied field, while the reverse domain occurs in the FGRs at higher reverse applied field. The micromagnetic simulation results also confirm the above magnetization reversal process. In addition, micromagnetic simulation results also show that the orientation of the grains also affects the pinning strength, besides the grain size. 展开更多
关键词 hot-deformed ND-FE-B magnet HETEROGENEOUS MICROSTRUCTURE Magnetization reversal COERCIVITY mechanism Rare earths
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Coercivity enhancement of Ce-containing hot-deformed magnets by grain boundary diffusion of DyF_(3) 被引量:3
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作者 Bin Chen Jinyun Ju +5 位作者 Wenzong Yin Xu Tang Renjie Chen Aru Yan Longquan Hou Yeyuan Du 《Journal of Rare Earths》 SCIE EI CAS CSCD 2022年第2期289-295,I0004,共8页
The samples with full density were prepared by hot pressing the the melt-spun powders mixed with DyF_(3)powders of different mass fractions followed by hot-deformation process.The magnetic properties and temperature d... The samples with full density were prepared by hot pressing the the melt-spun powders mixed with DyF_(3)powders of different mass fractions followed by hot-deformation process.The magnetic properties and temperature dependence of coercivity were obtained by BH tracer and VSM,respectively.The microstructure were analyzed by scanning electron microscopy(SEM)and transmission electron microscopy(TEM).The coercivity of Ce-containing hot-deformed magnets is increased from 1.41 to 1.95 T by grain boundary diffusion of 3 wt%DyF_(3),and is further enhanced to 2.05 T after annealing treatment.The thermal stability of coercivity and remanence is improved.The annealing condition in this work crucially plays a role in thickening the grain boundary phase.Microstructure analysis reveals that the continuous and thick grain boundary phase formed after DyF_(3)diffusion can weaken the magnetic coupling between grains,and suppress the platelet shaped grain size and the aspect ratio.The Dycontaining shell structure formed by the partial diffusion of Dy into the main phase can increase the magnetic anisotropy field,which is the main reason for the coercivity improvement.After optimizing the structure by DyF_(3)diffusion,the"dendritic-like"reverse domain is transformed into the"dot scatteredlike"reverse domain. 展开更多
关键词 Ce-containing hot-deformed magnet COERCIVITY Grain boundary phase Dy-containing shell structure Rare earths
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Effect of Pr-Ga dual-alloys diffusion on magnetic properties and thermal stability of hot-deformed PrNd-Fe-B magnets 被引量:2
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作者 Longquan Hou Jinyun Ju +6 位作者 Wenzong Yin Xu Tang Renjie Chen Ailin Xia Yeyuan Du Ruihua Du Aru Yan 《Journal of Rare Earths》 SCIE EI CAS CSCD 2022年第3期457-461,I0004,共6页
To investigate the influence of the addition of Pr-Ga alloys on magnetic properties and morphology of materials,the hot-deformed PrNd-Fe-B magnets were prepared by the addition of Pr-Ga alloys using a dual-alloys diff... To investigate the influence of the addition of Pr-Ga alloys on magnetic properties and morphology of materials,the hot-deformed PrNd-Fe-B magnets were prepared by the addition of Pr-Ga alloys using a dual-alloys diffusion.The room-temperature coercivity of the hot-deformed PrNd-Fe-B magnets increases substantially from 1.68 to 2.34 T,while the remanence decreases from 1.42 to 1.24 T,by the addition of 5 wt%Pr-Ga alloys.Moreover,the thermal stability of coercivity improves from-0.46%/℃to-0.42%/℃.Two types of grain boundary phases(PrNd-rich and PrNd-Ga-rich)are generated at grain boundaries by microstructural analysis,resulting in the decrease of Fe element concentration from more than 60%to about 10%at grain boundaries.The decrease of ferromagnetic element concentration at grain boundaries and the refinement of grain are considered to be the main reasons for the improvement of coercivity and thermal stability. 展开更多
关键词 hot-deformed PrNd-Fe-B Dual-alloys diffusion Magnetic properties Rare earths
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Analysis on deformation and texture formation mechanism of hot-deformed Nd-Fe-B magnets based on heterogeneous structure evolution 被引量:2
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作者 Yuyang Tang Yuqing Li +5 位作者 Xiaochang Xu Ming Yue Weiqiang Liu Hongguo Zhang Qingmei Lu Weixing Xia 《Journal of Materials Science & Technology》 SCIE EI CAS CSCD 2021年第21期28-35,共8页
In this paper, microstructure, micromagnetic structure, texture, together with magnetic properties of the hot-deformed(HD) Nd-Fe-B magnets were systematically studied to understand the deformation process and the form... In this paper, microstructure, micromagnetic structure, texture, together with magnetic properties of the hot-deformed(HD) Nd-Fe-B magnets were systematically studied to understand the deformation process and the formation mechanism of c-axis texture. The results show that the platelet grains are formed in the fine-grain regions at the initial stage of the deformation. As the amount of deformation increases, the proportion of platelet grains increases and arranges gradually, causing the formation of c-axis texture, till the grain merging occurres when the deformation is excessive. It should be noted that the rare earth-rich phase in the fine-grained region slowly diffuses to the coarse-grained region where only grain growth can be observed during deformation. The deformation mechanism and formation of c-axis texture in HD Nd-Fe-B magnets can be deduced to be accomplished by the processes of dissolution-precipitation diffusion, grain rotation and grain arrangement, based on the characterization of microstructure and texture evolution. Also, approaches to optimize the preparation process and magnetic properties of the hot-deformed Nd-Fe-B magnets were discussed. 展开更多
关键词 hot-deformed Nd-Fe-B magnet Heterogeneous microstructure Deformation mechanism C-axis texture COERCIVITY
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Preparation and properties of hot-deformed magnets processed from nanocrystalline/amorphous Nd-Fe-B powders 被引量:1
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作者 Peng Zhao Yang Luo +4 位作者 Dun-Bo Yu Hai-Jun Peng Wen-Long Yan Zi-Long Wang Xin-Yuan Bai 《Rare Metals》 SCIE EI CAS CSCD 2021年第8期2033-2039,共7页
The hot-deformed magnets processed from nanocrystalline/amorphous Nd-Fe-B powders were preparedunderdifferenthot-pressingtemperatures(600-750℃,at intervals of 25℃)by the self-made hotpressing equipment.The microstru... The hot-deformed magnets processed from nanocrystalline/amorphous Nd-Fe-B powders were preparedunderdifferenthot-pressingtemperatures(600-750℃,at intervals of 25℃)by the self-made hotpressing equipment.The microstructure and magnetic properties of hot-deformed magnets prepared at different temperatures were also investigated.When the temperature is above 650℃,the density of magnet reaches 7.5 g·cm^(-3).The optimum magnetic properties of magnetic induction intensity of B_(r)=1.3 T,optimum energy product of(BH)_(max)=282.5 kJ·m^(-3),intrinsiccoercivityof H_(cj)=1130.0 kA·m-1 of hot-deformed magnets are obtained at hot-pressing temperature of 650℃.X-ray diffractometer pattern shows that the(00 L)texture has been obtained.For the microstructural characteristic,on the one hand,the good magnetic performance is attributed to the fine platelet-like grains with an average length of 410-440 nm at the hot-pressing temperature range from625 to 675℃.On the other hand,the unaligned coarse grains are observed in all the samples.And the areal fraction of those is gradually increasing with the rise of the hot-pressing temperature,which tends to deteriorate the magnetic properties.The composition map shows the accumulation of Nd/Pr-rich phase in the coarse grains’region. 展开更多
关键词 Nanocrystalline/amorphous powders Hotpressing temperature hot-deformed Magnets Magnetic properties Microstructure
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Sandwiched structure of hot-deformed Nd-Fe-B permanent magnets processed by Nd-Cu eutectic alloys diffusion
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作者 Longquan Hou Jinyun Ju +5 位作者 Xu Tang Renjie Chen Wenzong Yin Aru Yan Bin Chen Yeyuan Du 《Journal of Rare Earths》 SCIE EI CAS CSCD 2021年第8期993-997,共5页
A series of sandwiched structures with different near-surface mass fractions x(x=3 wt%,4 wt%,5 wt%)was employed to develop high-coercivity hot-deformed Nd-Fe-B magnets by the addition of 2 wt%Nd-Cu eutectic alloys via... A series of sandwiched structures with different near-surface mass fractions x(x=3 wt%,4 wt%,5 wt%)was employed to develop high-coercivity hot-deformed Nd-Fe-B magnets by the addition of 2 wt%Nd-Cu eutectic alloys via adjusting the middle thickness and near-surface thickness.The designed magnet with a pronounced composite structure shows a 23% increase in coercivity with a 6% loss of remanence by adjusting the sandwiched structure at 4 wt% Nd-Cu eutectic alloys in the near-surface regions.The results indicate that the near-surface Nd-Cu-rich "shell" structure can effectively suppress the magnetization reversal of overall magnets,enhancing the coercivity.With the help of loading stress,Nd-Cu liquid enriched at the near-surface regions of the sample is infiltrated into the Nd-Cu-lean middle region,resulting in a concentration gradient.Microstructure characterizations further demonstrate that the infiltrated Nd-Cu eutectic plays a critical role in inhibiting grain growth and intergranular magnetic interaction.The optimized microstructure features suppress the reversed magnetization process,which makes a positive contribution to coercivity. 展开更多
关键词 ND-FE-B hot-deformed magnet Sandwiched structure Rare earths
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Development of Microalloyed Medium-Carbon Steel with Improved Toughness
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作者 Wang Qi Li Guifen Dong Han 《Journal of Iron and Steel Research International》 SCIE EI CAS CSCD 1996年第1期37-42,共6页
The application of the hot-rolled micronlloyed medium-carbon steel is limited due to its lower toughness compared with quenched and tempered steels.A high strength microalloyed medium-carbon steel has been developed t... The application of the hot-rolled micronlloyed medium-carbon steel is limited due to its lower toughness compared with quenched and tempered steels.A high strength microalloyed medium-carbon steel has been developed to meet the increasing demand for eliminating heat treatment.The effects of chemical compositions,hot-deforming temperatures and cooling rates after hot-deforming on mechanical properties of the steel were investigated.Attention was given to the steel toughness above the required value for safety components in application.The basic microstructural variables controlling the properties were discussed.It is demonstrated that toughness and machinability can be improved through the addition of 0.5%Si,0.5%S and 0.01%Ti.Toughness can be further improved by controlling hot-deforming temperature and subsequent cooling rate. 展开更多
关键词 microalloyed steel medium-carbon steel TOUGHNESS hot-deforming temperature cooling rate
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FLOW STRESS OF STEEL 55SiMnVB AT HIGH TEMPERATURES AND HIGH STRAIN RATES
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作者 ZHAO Jiarong YANG Jie Wuhan Iron and Steel University,Wuhan,China ZHAO Jiarong,associate professor,Faculty of Rolling,Wuhan Iron and Steel University,Wuhan 430081,China 《Acta Metallurgica Sinica(English Letters)》 SCIE EI CAS CSCD 1990年第8期110-114,共5页
Based on the analyses of hot-deformation mechanism of the steel,a new constitutive equation describing the flow stress of steels was derived.The flow stress data of steel 55SiMnVB have been determined at 900—1200℃,s... Based on the analyses of hot-deformation mechanism of the steel,a new constitutive equation describing the flow stress of steels was derived.The flow stress data of steel 55SiMnVB have been determined at 900—1200℃,strain rates of 1—100s^(-1)and true-strain of 0.08—0.8.An available evaluated formula on the flows tress has been obtained by means of non-linear regression.It can express clearly the physical process of hot-deformation. 展开更多
关键词 flow stress steel 55SiMnVB prediction model hot-deformation
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IMPROVED PROCESSING FOR MICROSTRUCTURES AND MECHANICAL PROPERTIES OF A COMMERCIAL PIPELINE STEEL
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作者 Y.C.Wang Y.S.Li +1 位作者 M.C.Zhao K.Yang 《Acta Metallurgica Sinica(English Letters)》 SCIE EI CAS CSCD 2005年第2期121-128,共8页
The transformation productions of hot-deformation simulation experiments were investigated using a Gleeble-1500 hot simulator for a commercial pipeline steel. Based on the investigation results, the improved thermo-me... The transformation productions of hot-deformation simulation experiments were investigated using a Gleeble-1500 hot simulator for a commercial pipeline steel. Based on the investigation results, the improved thermo-mechanical control processing (TMCP) schedules containing a two stage multi-pass controlled rolling coupled with moderate cooling rates were applied to hot rolling experiments and acicular ferrite dominated microstructure was obtained. Microstructures and mechanical properties of hot rolled plates were related to TMCP processing, and regression equations describing the relation between processing parameters and mechanical properties in the current TMCP were developed, which could be used to predict mechanical properties of the experimental steel during commercially processing. It was found that with an increase in cooling rate after hot rolling, grain size in the microstructure became smaller, the amount of polygonal ferrite decreased and acicular ferrite increased, and accordingly mechanical properties increased. 展开更多
关键词 hot-deformation simulation thermo-mechanical control processing acicular ferrite dominated microstructure
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Coercivity mechanism of high-performance anisotropic heterostructure SmCo_(5)magnets
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作者 Yuan Teng Yuqing Li +9 位作者 Weiqiang Liu Xiaochang Xu Zhanjia Wang Jianjun Yang Dongtao Zhang Hongguo Zhang Qingmei Lu Qiong Wu Weixing Xia Ming Yue 《Journal of Rare Earths》 SCIE EI CAS CSCD 2024年第10期1882-1888,共7页
Due to its large magnetocrystalline anisotropy field and high Curie temperature,SmCo-based magnets are irreplaceable in high-temperature applications,The hot-deformed SmCo-based magnets are especially attractive for t... Due to its large magnetocrystalline anisotropy field and high Curie temperature,SmCo-based magnets are irreplaceable in high-temperature applications,The hot-deformed SmCo-based magnets are especially attractive for their excellent corrosion resistance,making them more suitable for harsh environments.However,it is still challenging for hot-deformed SmCo-based magnets to obtain high magnetization and high coercivity simultaneously.Therefore,it is necessary to analyze the relationship between its microstructure and magnetic properties and explore its magnetic hardening mechanism to guide the further improvement of magnetic properties.In this paper,the anisotropic heterostructure SmCo_(5)magnet was prepared by combining large height-reduction and introducing a nano-grained Smrich phase.Strong c-axis texture,(BH)m of 16.1 MGOe,and H_(ci)of 9.6 kOe were obtained via the heterostructure with SmCo_(5)micron-grain and Sm-rich nano-scale precipitates.The magnetic domain observation and technical magnetization analysis demonstrate that the coe rcivity mechanism is dominated by nucleation.The results also show that the smooth and Sm-rich precipitated grain boundary provides weak pinning effects.It provides a reference for the development of high-pe rformance nanocrystalline SmCo_(5)magnets. 展开更多
关键词 Permanent magnet HETEROSTRUCTURE Rare earths Coercivity mechanism hot-deformed SmCo magnet
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Texture development and grain boundary phase formation in Ce-and Ce-La-substituted Nd-Fe-B magnets during hot-deformation process
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作者 Ga-Yeong Kim Tae-Hoon Kim +4 位作者 Hee-Ryoung Cha Sang-hyub Lee Dong-Hwan Kim Yang-Do Kim Jung-Goo Lee 《Journal of Materials Science & Technology》 SCIE EI CAS CSCD 2022年第31期71-79,共9页
In this study,the influence of Ce-and Ce-La-substitution for Nd in Nd-Fe-B magnets on their magnetic and microstructural changes in the course of the hot-deformation process was investigated to gain insight into furth... In this study,the influence of Ce-and Ce-La-substitution for Nd in Nd-Fe-B magnets on their magnetic and microstructural changes in the course of the hot-deformation process was investigated to gain insight into further reducing the Nd content in fine-grained Nd-Fe-B hot-deformed magnets.We found that the[001]texture and microstructure of the RE-rich grain boundary phases,which are the factors that de-termine the remanence and coercivity of hot-deformed magnets,were deteriorated by the Ce-and Ce-La-substitution.This is because the volume fraction of the RE-rich liquid formed in the grain boundaries during the hot-press and hot-deformation decreased due to the Ce-and Ce-La-substitution,thereby in-creasing the friction between the 2:14:1 grains while the c-axes of grains were aligned by grain rotation and decreasing the RE concentration of grain boundary phases.In particular,the Ce-La-co-substitution further prevented the liquid formation within the grain boundaries of the magnets during hot-press and hot-deformation because the wettability of the RE-rich liquid on the 2:14:1 grains became poor when La was substituted for Nd in the 2:14:1 grains.These results indicate that there is room for further im-provement in both the remanence and coercivity of the Ce-and Ce-La-substituted magnets by intro-ducing additional liquid into the grain boundaries prior to hot-press and hot-deformation.By applying the Nd-Cu infiltration process to the melt-spun ribbons(intermediate infiltration,I-infiltration),both the remanence and coercivity of the Nd-saving(Nd 0.7 Ce 0.3)-Fe-B and(Nd 0.7 Ce 0.225 La 0.075)-Fe-B hot-deformed magnets were successfully improved. 展开更多
关键词 Nd-Fe-B magnets hot-deformation Nd-saving Ce-substitution La-substitution INFILTRATION
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