检索结果-南通市图书馆

Thermal stability improvement and microstructure optimization of high cobalt content Nd-Fe-B magnets via terbium grain boundary diffusion

在线全文

学校读者我要写书评

暂无评论

Journal of Rare Earths 2024年第8期42卷 1531-1538,I0004页

作者： Jiyuan Xu Ruiyang Meng Jing Liu Jiateng Zhang Rui Han Yikun Fang Shengzhi Dong Wei Li Division of Functional Materials research Central Iron and Steel Research InstituteBeijing100081China

The substitution of Fe by Co in the 2:14:1 phase is an effective method to increase the Curie temperature and enhance the thermal stability of the Nd-Fe-B ***,the accumulation of Co ele ment at the grain boundaries(GBs) changes the GBs from nonmagnetic to ferromagnetic and causes the thinlayer GBs to become rare,In this paper,the method of diffusing Tb element was chosen to improve the microstructure and temperature stability of high-Co *** original sintered Nd_(28.5)Dy_(3)-CO_(x)e_(bal)M_(0.6)B_(i)(x=0,6 wt%,12 wt%;M = Cu,Al,Zr) magnets with different Co contents were diffused with Tb by grain boundary diffusion(GBD).After GBD,high-Co magnets exhibit more continuously distributed thin-layer GBs,and their thermal stability is significantly *** high-Co magnets(x=6 wt%),the absolute value of the temperature coefficient of coercivity decreases from 0.603%/K to0.508%/K in the temperature range of 293-413 K,that of remanence decreases from 0.099%/K to 0.091%/K,and the coercivity increases from 18.44 to 25.04 *** electron microscopy(TEM)characterization reveals that there are both the 1:2 phase and the amorphous phase in the high-Co magnet before and after GBD,EDS elemental analysis shows that Tb element is more likely to preferentially replace the rare earth elements in the 2:14:1 main phase than in the 1:2 phase and the amorphous *** concentration of Tb at the edge of the main phase is much higher than that in the 1:2phase and amorphous phase,which is beneficial to the improvement of the *** preferential replacement of Tb elements at the edge of the 2:14:1 phase and thin-layer GBs with a more continuous distribution are synergistically responsible for improving the thermal stability of high-Co *** study indicates that GBD is an effective method to improve the microstructure and thermal stability of high-Co magnets.

关键词： Nd-Fe-B magnets Coercivity Grain boundary diffusion Thermal stability Micro structure Rare earths

Damping capacity of Fe_(83)Ga_(17) magnetostrictive alloy under magnetic field

在线全文

学校读者我要写书评

暂无评论

Rare Metals 2024年第1期43卷 402-409页

作者： Shao-Wen Yan Xing Mu Bing-Jie Liu Li-Hong Xu Shi-Hai Guo Yan Qi Hong-Ping Zhang Department of Functional Material research Central Iron and Steel Research InstituteBeijing 100081China

The damping performance of Fe_(83)Ga_(17) alloys has been investigated in the static magnetic field (H). The results demonstrate that the damping peak value can be adjusted between 0.020 and 0.085 under the magnetic f... 详细信息

关键词： alloy magnetic alloys

Fabricating functionally graded Fe-Cr-Co permanent magnetic alloys via laser powder bed fusion

在线全文

学校读者我要写书评

暂无评论

Journal of iron and steel research International 2024年第3期31卷 729-737页

作者： Ya-zhou He Ya-qing Hou Peng Shen Hao Zhang Dong Zhou Hang Su central iron and steel research institute Co. Ltd.Beijing 100081China Material Digital R&D Center China Iron and Steel Research Institute Group Co.Ltd.Beijing 100081China

Laser powder bed fusion(LPBF)in-situ alloying technology offers the possibility to construct gradient materials with varied structures and *** graded Fe-Cr-Co permanent magnetic alloys were fabricated by LPBF and in-situ alloying mixed powders of Fe,Cr,and Co *** effects of different Fe,Cr and Co contents on the microstructure,magnetic properties and hardness of Fe-Cr-Co alloys prepared by LPBF were *** as-built Fe-Cr-Co alloys present a single body-centered-cubic phase and have a homogeneous distribution of *** mechanical properties and magnetic properties of the compositionally graded sample show a gradient *** the increase in Cr content,the Vickers hardness of the sample increases,and the saturation magnetization of the sample *** optimal magnetic properties in an isotropic state are given as coercivity HcB=21.65 kA/m,remanence Br=0.70 T and energy product(BH)_(max)=5.35 kJ/m^(3),which are comparable to or higher than the reported magnetic properties in an isotropic state prepared by traditional powder *** in-situ alloying technology has the potential to further explore Fe-Cr-Co magnetic materials,such as those consisting of multiple or more constituent elements,and to maximize the compositional flexibility of magnetic materials.

关键词： Fe-Cr-Co alloy Laser powder bed fusion In-situ alloying Functional material Magnetic property

research progress in CALPHAD assisted metal additive manufacturing

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

china Foundry 2024年第4期21卷 295-310页

作者： Ya-qing Hou Xiao-qun Li Wei-dong Cai Qing Chen Wei-ce Gao Du-peng He Xue-hui Chen Hang Su china iron&steel research institute Group Beijing 100081China Thermo-Calc Software AB SolnaSE-169Sweden KTH Royal institute of Technology StockholmSE-100Sweden central iron and steel research institute Beijing 100081China

Metal additive manufacturing(MAM)technology has experienced rapid development in recent *** both equipment and materials progress towards increased maturity and commercialization,material metallurgy technology based on high energy sources has become a key factor influencing the future development of *** calculation of phase diagrams(CALPHAD)is an essential method and tool for constructing multi-component phase diagrams by employing experimental phase diagrams and Gibbs free energy models of simple *** combining with the element mobility data and non-equilibrium phase transition model,it has been widely used in the analysis of traditional metal *** development of CALPHAD application technology for MAM is focused on the compositional design of printable materials,the reduction of metallurgical imperfections,and the control of microstructural *** endeavor carries considerable theoretical and practical *** paper summarizes the important achievements of CALPHAD in additive manufacturing(AM)technology in recent years,including material design,process parameter optimization,microstructure evolution simulation,and properties ***,the limitations of applying CALPHAD technology to MAM technology are discussed,along with prospective research directions.

关键词： metal additive manufacturing CALPHAD integrated computational material engineering powder bed fusion material design microstructure simulation

Effect of Ball Milling Time on Microstructure and Hydrogen Storage Properties of Nd_(5)Mg_(41)Ni Alloy

在线全文

学校读者我要写书评

暂无评论

Acta Metallurgica Sinica(English Letters) 2024年第7期37卷 1201-1214页

作者： Zeming Yuan Chenxu Liu Xiaoming Li Yongqi Sui Zhonggang Han Tingting Zhai Dianchen Feng Yanghuan Zhang Instrumental Analysis Center Inner Mongolia University of Science and TechnologyBaotou014010China Department of Functional Material research Central Iron and Steel Research InstituteBeijing100081China

Mg-based alloys must be dehydrogenated at high pressure and temperatures, limiting their practical application. In this paper, Nd_(5)Mg_(41)Ni alloy was prepared by vacuum melting, and the as-cast alloy was ball milled for 5 h, 10 h, 15 h, and 20 h. The effect of ball milling time on the microstructure and hydrogen storage properties of the alloy was systematically studied. The alloy comprises Nd_(5)Mg_(41), NdMg_(12), NdMg_(3), and Mg_(2)Ni phases. The Nd_(5)Mg_(41)Ni alloy milling for 10 h can reach 95% of the saturated hydrogen absorption at 553 K by 40 s, and the alloy can desorb hydrogen only by 20 min. The dehydrogenation activation energy is only 99.9 kJ/mol H_(2). Ball milling makes the alloy produce many nanocrystalline and amorphous structures. The nano-grain boundary provides a channel for the diffusion of hydrogen atoms, and the high energy at the grain boundary provides energy for the phase deformation nucleus. Ball milling leads to the refinement of alloy particles and shortens the diffusion distance of hydrogen atoms to the interior of alloy particles. Defects such as twins and dislocations generated by milling provide energy for the phase deformation nucleus during the hydrogen absorption and desorption.

关键词： Hydrogen storage materials Magnesium-base alloy Ball milling Nanocrystal Kinetics

High-performance anisotropic SmCo-based magnet with novel microstructure

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 Rare Earths 2024年第8期42卷 1539-1545,I0005页

作者： Yingchang Li Zicao Xing Nengjun Yu Zesong Ren Minxiang Pan Qiong Wu Hongliang Ge Minggang Zhu Wei Li College of Materials and Chemistry China jiliang UniversityHangzhou 310018China Division of Functional Materials research Central Iron and Steel Research InstituteBeijing 100081China

A novel micro structure of magnetically anisotropic Sm Co-based magnet with high-performance is *** magnet consists of SmCo_(7)-H(TbCu_(7)-hexagonal type),Sm_(2)Co_(17)-H(Th_(2)Ni_(17)-hexagonal type)and SmCo_(3)-R(SmCo_(3)-rhombohedral type)*** maximum magnetic energy product of the magnet is 231.69 kj/m^(3),and the intrinsic coercivity is 1005.47 kA/*** outstanding intrinsic coercivity temperature coefficient(β)of-0.125%/K between 298 and 773 K is obtained,which is very close to theβof commercial high-temperature Sm_(2)Co_(17)-based sintered *** initial magnetization curve indicates that the coercivity mechanism is controlled by a domain wall pinning *** SmCo_(3)-R lamellar phase may be a potential pinning center or self-pinning *** microstructure of the magnet is different from that of any previous SmCo-based *** findings provide a new idea for preparing high-performance SmCo-based permanent magnets.

关键词： Rare earths Permanent magnet Composite magnet Melt-spinning Microstructure

Particle size dependence of the microsegregation and microstructure in the atomized Ni-based superalloy powders:Theoretical and experimental study

在线全文

学校读者我要写书评

暂无评论

Journal of Materials Science & Technology 2024年第4期171卷 54-65页

作者： Jikang Li Mingsheng Yang Yunfei Cai Yuanyuan Zhang Qingshuai Feng Jiantao Liu Tong Liu Key Laboratory of Aerospace Materials and Performance(Ministry of Education)School of Materials Science and Engineering Beihang UniversityBeijing 100191China central iron and steel research institute Beijing 100081China

The microstructure and microsegregation of atomized powder,which depend on their sizes,are of great importance to the mechanical properties of the consolidated bulk ***,it is necessary to reveal the relationship between particle size and powder *** effects of particle size on the so-lidification characterization of the atomized Ni-based superalloy powders were studied via finite element *** on the simulations,a model was developed to predict the microsegregation and mi-crostructure of atomized powders with different sizes and study the influence of thermal history on the powder attributes during the atomization *** radiation heat transfer and temperature gradi-ent within the rapid solidification alloy powders were taken into account in this *** validating the accuracy of the model,the predictions of the present model were compared with the microsegregation and microstructure of the specific size powder close to the screen mesh *** results showed that mi-crostructure depended primarily on the temperature gradient within the powder,while the solidification rate had a more significant effect on the *** model predicted microstructure features in agreement with the experiment,and for microsegregation,the deviations of prediction for most ele-ments were less than 10%.This work provides a new model to precisely predict the microsegregation and microstructure of the atomized alloy powders and sets a foundation to control the powder features for various engineering applications.

关键词： Particle size Solidification microstructure Microsegregation Numerical simulation

Multi-performance evaluation of high-throughput accelerated corrosion test for high-strength low-alloy 921A steel

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 iron and steel research International 2024年第5期31卷 1260-1278页

作者： Cong-cong Du Ming-hua Qin Zhan-fang Wu Dong-ling Li Lei Zhao Xiang-yang Li Hai-zhou Wang beijing Advanced Innovation Center for Materials Genome Engineering National Center for Materials Service SafetyUniversity of Science and Technology BeijingBeijing100083China china iron and steel research institute Group Co. Ltd.Beijing100081China beijing Advanced Innovation Center for Materials Genome Engineering Central Iron and Steel Research InstituteBeijing100081China

The corrosion behavior of high-strength low-alloy 921A steel in a simulated marine atmospheric environment was studied using a high-throughput experimental *** corrosion behavior,corrosion morphology,and corrosion products of 921A steels were analyzed using various techniques,including corrosion mass loss method,polarization curve,white-light interferometry,scanning electron microscopy,energy-dispersive spectrometry,microbeam X-ray fluorescence spectrometry,X-ray diffraction technique,and X-ray photoelectron *** test results indicated that 921A steel exhibits better corrosion resistance than Q450NQR1 steel in simulated harsh atmospheric environments,as evidenced by a lower corrosion mass loss rate throughout the corrosion *** corrosion products of both steels consisted ofα-FeOOH,Fe_(3)O_(4),andγ-FeOOH,withα-FeOOH being more prevalent in the rust layer of 921A steel than in Q450NQR1 *** inner rust layer of 921A steel also exhibited an appositional enrichment region of Cr,Ni,Mo,and V,leading to its superior corrosion resistance compared to that of Q450NQR1 *** efficacy of high-throughput accelerated corrosion experimental methods was highlighted for evaluating the corrosion resistance of steel materials in harsh environmental *** findings suggest that 921A steel exhibits better corrosion resistance compared to Q450NQR1 steel and has the potential to be more suitable in harsh marine atmospheric *** characterization of the rust layer structures and composition reveals the parallel enrichment of certain elements in the inner rust layer of 921A steel,which enhances its corrosion resistance.

关键词： Atmospheric corrosion High-throughput experimental method High-strength low-alloy steel Corrosion characteristics Rust layer Element enrichment

Study on tungsten sintering temperature field based on electromagnetic simulation and computational fluid dynamics

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Tungsten 2024年第2期6卷 355-366页

作者： Lu-Yan Wang Yue-Guang Yu Jian-Xin Dong Kai-Ping Du Shan-Yu Liu Cao-Bing Li University of Science and Technology beijing Beijing 100083China BGRIMM Technology Group Beijing 100160China china iron&steel research institute Group Beijing 100081China

In order to study the influence of various sintering variables more intuitively and clearly,electromagnetic field analysis and computational fl uid dynamics are used to analyze the infl uence of gas flow,heating power and other process parameters on the temperature range of medium-frequency sintering in this *** results indicate that the uniformity of temperature fi eld is determined by the gas flow rate and heating *** the heating power is 50 kW,the stable temperature drops about 10 K for every 1 m^(3)·h^(−1)increase of hydrogen *** peak value of the maximum temperature diff erence on the tungsten rods gradually increases with the increase of the hydrogen flow rate,and it appears slightly *** temperature distribution of tungsten rods in furnace is similar with diff erent hydrogen flow *** the same time,the closer to the furnace wall,the higher the temperature of the tungsten *** temperature diff erence between tungsten rods mainly occurred within 1 h after the beginning of *** the heating power can improve the stable temperature,but has little eff ect on the heating *** heating power can increase the peak value of the maximum temperature diff erence on the tungsten rods,but has little eff ect on the occurrence time of the peak value of the maximum temperature diff erence on the tungsten *** the heating power will increase the temperature diff erence of a single tungsten rod,but the temperature diff erence of a single tungsten rod never exceeds 65 *** study can be used to guide the process optimization *** with numerical simulation calculation,the sintering parameters with low energy consumption and high temperature uniformity can be quickly and eff ectively found,thus improving the microstructure and properties of sintered tungsten products.

关键词： Tungsten products Sintering Hydrogen flow rate Heating power