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| 1 | COUPLED NUMERICAL SIMULATION ON COLD ROLLER'S TEMPERATURE FIFLD-PHASE TRANSFORMATION - STRESS FIELD DURING ITS QUENCHING PSOCESS显示文摘Complicated changns occur inside the steel parts during quenching process. The abruptly changed boundary conditions make the temperature field,micro - structure and stress field change dramatically in very short time, and these variables take a contact interactions in the whole process. In this paper, a three dimensional non - linear mathematical model for queeching process has been founded and the numerical simulation on temperature field,microstructre and stress field has been realized.In the FEM analysis, the incremental iteration method is used to deal with such complicated nonlinear as boundary nonlinear, physical property nonlinear,transformation nonlinear etc.The effect of stress on transformation kinetics has been considered in the calculation of microstructure. In the stress field anal- ysis,a thermo- elasto - plastic model has been founded, which considers such factors as transforma- tion strain,transformation plastic strain, themal strain and the effect of temperature and transforma- tion on mechanical propertier etc. The transient temperature field, microstructure distribution and stress field of the roller on any time can be displayed vividly,and the cooling curve and the changes of stress on any position can also be given. | J. F. Gu J. S. Pan M. J. Hu and F. F. Shen (School of Materials Science and Engineering, Shanghai Jiao Tong University, Shanghai 200030, China) | 2000 | Acta Metallurgica Sinica(English Letters)2000，13，1： | 13 |
| 2 | Strengthening iron enrichment and dephosphorization of high-phosphorus oolitic hematite using high-temperature pretreatment显示文摘The efficient development and utilization of high-phosphorus oolitic hematite is of great strategic significance for the sustainable supply of iron-ore resources in China.In this paper,the mechanism of high-temperature pretreatment for enhancing the effect of iron enrichment and dephosphorization in the magnetization roasting–leaching process was studied by X-ray diffraction(XRD),vibration sample magnetometer(VSM),scanning electron microscopy and energy dispersive spectrometry(SEM–EDS).Compared with the process without high-temperature pretreatment,the iron grade of the magnetic separation concentrate after high-temperature pretreatment had increased by 0.98%,iron recovery rate had increased by 1.33%,and the phosphorus content in the leached residue had decreased by 0.12%.High-temperature pretreatment resulted in the dehydration and decomposition of hydroxyapatite,the dehydration of limonite and the thermal decomposition of siderite,which can produce pores and cracks and weaken the compactness of the ore,improve the magnetization characteristics of roasted ore,and strengthen the iron enrichment and dephosphorization during the magnetization roasting and leaching process. | Wen-tao Zhou Yue-xin Han Yong-sheng Sun Yan-jun Li | 2020 | International Journal of Minerals,Metallurgy and Materials2020，27，4： | 13 |
| 3 | Phase transformation refinement of coarse primary carbides in M2 high speed steel | Fu-sheng PAN Wei-qing WANG Ai-tao TANG Li-zhi WU Ting-ting LIU Ren-ju CHENG | 2011 | Progress in Natural Science:Materials International2011，21，2： | 10 |
| 4 | Containerless rapid solidification of undercoolecl Cu-Co peritectic alloys显示文摘Droplets of Co-16%Cu and Co-71.6%Cu peritectic alloys were solidified during container-less processing in a 3-m drop tube. The microstructures of Co-16%Cu alloy droplets were characterized by dendritic or equiaxed α-Co phase with a small amount of Cu-rich solid solution distributed on α-Co phase boundaries. Two thresholds of droplet diameter were observed for Co-16%Cu alloy at which 'equiaxed-dendritic-equiaxed' morphological transitions occur to primary α-Co phase. This conspicuous refinement of primary α-Co grains results from the fragmentation of α-Co dendrites caused by re-calescence effect. For Co-71.6% Cu alloy, the primary a-Co phase forms as coarse columnar dendrites in large droplets and equiaxed dendrites in small droplets. Theoretical calculations indicate that Marangoni migration contributes more to the growth of disperse Co-rich spheres by stimulating collision and coalescence than Stokes motion caused by the residual gravity in the falling Co-71.6%Cu alloy droplets. | 曹崇德 王楠 魏炳波 | 2000 | Science China Mathematics2000，43，12： | 8 |
| 5 | Recent developments in computational modelling of nucleation in phase transformations显示文摘Nucleation is one of the most common physical phenomena in physical,chemical,biological and materials sciences.Owing to the complex multiscale nature of various nucleation events and the difficulties in their direct experimental observation,development of effective computational methods and modeling approaches has become very important and is bringing new light to the study of this challenging subject.Our discussions in this manuscript provide a sampler of some newly developed numerical algorithms that are widely applicable to many nucleation and phase transformation problems.We first describe some recent progress on the design of efficient numerical methods for computing saddle points and minimum energy paths,and then illustrate their applications to the study of nucleation events associated with several different physical systems. | Lei Zhang Weiqing Ren Amit Samanta Qiang Du | 2016 | npj Computational Materials2016，，1： | 8 |
| 6 | Prediction of the Residual Welding Stress in 2.25Cr-1Mo Steel by Taking into Account the Effect of the Solid-State Phase Transformations显示文摘A computational approach based on the thermal elastic plastic finite element method was developed for predicting welding residual stress in low carbon alloyed steel welds by taking into account the effect of the solid-state phase transformations. The kinetics of phase transformations was described by Johnson Mehl Avrami Kolmogrov (JMAK) equation for bainitic transition and by Koistinen-Marburger (K-M) relationship for martensitic transition. Moreover, an additive rule depending on volumetric phase fraction was adopted to represent the material property changes during heating and cooling. Consequently, the residual welding stresses in a 2.25Cr1Mo steel TIG welded plate were computed. Early calculation results suggest that the bainitic and martensitic transformations took place in the weld the heat-affected zone drastically reduce the residual longitudinal tensile stress in the region. | Dean DENG Yangang TONG Ninshu MA Hidekazu MURAKAWA | 2013 | Acta Metallurgica Sinica(English Letters)2013，26，3： | 7 |
| 7 | Thermally induced evolution of phase transformations in gas hydrate sediment显示文摘Thermally induced evolution of phase transformations is a basic physical-chemical process in the dissociation of gas hydrate in sediment (GHS). Heat transfer leads to the weakening of the bed soil and the simultaneous establishment of a time varying stress field accompanied by seepage of fluids and deformation of the soil. As a consequence, ground failure could occur causing engineering damage or/and environmental disaster. This paper presents a simplified analysis of the thermal process by assuming that thermal conduction can be decoupled from the flow and deformation process. It is further assumed that phase transformations take place instantaneously. Analytical and numerical results are given for several examples of simplified geometry. Experiments using Tetra-hydro-furan hydrate sediments were carried out in our laboratory to check the theory. By comparison, the theoretical, numerical and experimental results on the evolution of dissociation fronts and temperature in the sediment are found to be in good agreement. | ZHANG XuHui1*, LU XiaoBing1, LI QingPing2 & YAO HaiYuan2 1 Key Laboratory for Hydrodynamics and Ocean Engineering, Institute of Mechanics, Chinese Academy of Sciences, Beijing 100190, China 2 Research Centre, China Ocean Oil Co., Beijing 100027, China | 2010 | Science China(Physics,Mechanics & Astronomy)2010，53，8： | 7 |
| 8 | NUMERICAL SIMULATION OF FORGING AND SUBSEQUENT HEAT TREATMENT OF A ROD BY A FINITE VOLUME METHOD显示文摘A method to simulate processes of forging and subsequent heat treatment of an axial symmetric rod is formulated in eulerian description and the feasibility is investigated. This method uses finite volume mushes for troching material deformation and an automatically refined facet surface to accurately trace the free surface of the deforming material.In the method,the deforming work piece flows through fixed finite volume meshes using eulerian formulation to describe the conservation laws,Fixed finite volume meshing is particularly suitable for large three-dimensional deformation such as forging because remeshing techniques are not required, which are commonly considered to be the main bottelencek in the ssimulations of large defromation by using the finite element method,By means of this finite volume method, an approach has been developed in the framework of 'metallo-thermo-mechanics' to simulate metallic structure, temperature and stress/strain coupled in the heat treatment process.In a first step of simulation, the heat treatment solver is limited in small deformation hypothesis,and un- coupled with forging. The material is considered as elastic-plastic and takes into account of strain, strain rate and temperature effects on the yield stress.Heat generation due to deformation,heat con- duction and thermal stress are considered.Temperature - dependent phase transformation,stress-in- duced phase transformation,latent heat,transformation stress and strain are included.These ap- proaches are implemented into the commerical commercial computer program MSC/SuperForge and a verification example with experimental date is given as comparison. | P. R. Ding D. Y. Ju T. Lnouc and E. de Vries( 1) MSC Japan Ltd., Osaka,Japan 2) Saitama Institute of Technology,Saitama,Japan 3) Kyoto Universily, Kyoto, Japan 4) MacNeal - Schwendler (E. D. C. ) B. V., Gouda, The Netherlands) | 2000 | Acta Metallurgica Sinica(English Letters)2000，13，1： | 6 |
| 9 | High-resolution Rayleigh wave phase velocity maps from ambient noise tomography in North China显示文摘We presented high-resolution Rayleigh wave phase velocity maps at periods ranging from 5 s to 30 s in the northeast part of the North China Craton (NNCC). Continuous time-series of vertical component between October 2006 and December 2008, recorded by 187 broadband stations temporarily deployed in the NNCC region, have been cross-correlated to obtain estimated fundamental mode Rayleigh wave Green’s functions. Using the frequency and time analysis technique based on continuous wavelet transformation, we measured 3 667 Rayleigh wave phase velocity dispersion curves. High-resolution phase velocity maps at periods of 5, 10, 20 and 30 s were reconstructed with grid size 0.25°× 0.25°, which reveal lateral heterogeneity of shear wave structure in the crust and upper mantle of NNCC. For periods shorter than 10 s, the phase velocity variations are well correlated with the principal geological units in the NNCC, with low-speed anomalies corresponding to the major sedimentary basins and high-speed anomalies coinciding with the main mountain ranges. Within the period range from 20 s to 30 s, high phase velocity observed in eastern NCC is coincident with the thin crust, whereas low phase velocities imaged in central NCC is correlated to the thick crust. However, the low-velocity anomaly in the Beijing-Tianjin-Tangshan region displayed in the 20 s and 30 s phase maps may be associated with fluids. | Jiatie Pan Institute of Geophysics, China Earthquake Administration, Beijing 100081, China | 2012 | Earthquake Science2012，25，3： | 6 |
| 10 | Theoretical study of coexistence of ordering and spinodal decomposition显示文摘According to the conventional theory of solid solutions (the nearest neighbor atomic interaction model),ordering and spinodal decomposition/clustering are mutually exclusive processes.However,it has been found that the coexistence of ordering and spinodal decomposition (COSD) occurs in a large number of alloys.This fact gave a strong challenge to the conventional theory.A statistical investigation revealed that the COSD was closely related to large atomic-siae factors.It was thus proposed that the COSD stemmed from the long-range elastic interactions due to atomic-si?E disparity.In order to verify this idea,the formulism of concentration waves was applied to calculating the elastic interactions.The results proved that long-range atomic elastic interactions promoted both ordering and spinodal decomposition.A possible application of the COSD reaction was proposed,i.e.using this reaction to fabricate high-performance 'natural nano-alloys'. | 任晓兵 王笑天 T.Tadaki K.Shimizu | 1996 | Science China(Technological Sciences)1996，39，4： | 6 |
| 11 | Application of Yu' s theory and Cheng' s theory to alloy research | 刘志林 孙振国 李志林 | 1998 | Progress in Natural Science:Materials International1998，8，2： | 5 |
| 12 | 由相位噪声间接测量阿伦方差的研究显示文摘振荡器的频率稳定度在时域一般用阿伦方差表征,在频域一般用相位噪声谱密度函数表征,两者存在一定的数学转换关系,即可以由频域测量的相位噪声谱密度函数转换为时域的阿伦方差.t<0.1 ms时短期频率稳定度的时域测量非常困难.利用两者之间的转换关系对振荡器的时域稳定度进行了间接测量,并用实测数据进行了验证.
Abstract:
Frequency stability of oscillator commonly can be denoted by Allan variance in time domain, and by phase noise power spectrum density function in frequency domain. There is a definite transform relation of mathematics, it is to say that Allan variance of time domain can be obtained by transforming phase noise power spectrum density function, especially it is more applicable when τ < 0. 1 ms because it is very difficult to measure short - term frequency stability in time domain. The transformation relation between the two denotations of short-term frequency is used to measure Allan variance indirectly and validated by measured data. | 仲崇霞 夏振华 Chong-xia Zhen-hua | 2009 | 计量学报2009，，6： | 5 |
| 13 | EFFECT OF MICROSTRUCTURE ON THE HARDENING AND SOFTENING BEHAVIORS OF POLYCRYSTALLINE SHAPE MEMORY ALLOYS PART Ⅰ:MICROMECHANICS CONSTITUTIVE MODELING显示文摘The effects of microstructure and its evolution on the macroscopicsuperelastic stress-strain response of polycrystalline Shape Memory Alloy(SMA)arestudied by a microstructure-based constitutive model developed in this paper.Themodel is established on the following basis:(1)the transformation conditions of theunconstrained single crystal SMA microdomain(to be distinguished from the bulksingle crystal),which serve as the local criterion for the derivation of overall transfor-mation yield conditions of the polycrystal;(2)the micro-to macro-transition schemeby which the connection between the polycrystal aggregates and the single crystalmicrodomain is established and the macroscopic transformation conditions of thepolycrystal SMA are derived;(3)the quantitative incorporation of three microstruc-ture factors(i.e.,nucleation,growth and orientation distribution of martensite)intothe modeling.These microstructural factors are intrinsic of specific polycrystal SMAsystems and the role of each factor in the macroscopic constitutive response is quan-titatively modeled.It is demonstrated that the interplay of these factors will resultin different macroscopic transformation kinematics and kinetics which are responsiblefor the observed macroscopic stress-strain hardening or softening response,the latterwill lead to the localization and propagation of transformation bands in TiNi SMA. | 宋固全 孙庆平 黄克智 | 2000 | Acta Mechanica Sinica2000，16，4： | 5 |
| 14 | Effect of particle size on the transformation kinetics of flue gas desulfurization gypsum to α-calcium sulfate hemihydrate under hydrothermal conditions显示文摘The effect of particle size on the transformation kinetics of flue gas desulfurization (FGD)gypsum to α-calcium sulfate hemihydrate (α-HH)in calcium chloride (CaCl2)solutions was investigated to better guide value-added FGD gypsum use.Gypsum samples from different sources were sieved into several size groups,and their transformation rates were compared.The results showed that using FGD gypsum with a smaller particle size accelerated the transformation to α-HH.The size effect accelerated nucleation kinetics of α-HH rather than its crystal growth rate (that is,the thermodynamic driving force for the transformation changed little with particle size variation).Analysis using a kinetics model revealed that a smaller gypsum particle size lowered the overall activation energy barrier for the transformation.This is because the smaller gypsum particles had a larger relative specific surface area and thus provided more nucleation sites and crystalline defects to promote α-HH nucleation.A smaller particle size of FGD gypsum also gave a higher yield of fine α-HH particles because of the increased incidence of primary and secondary nucleation coupled with attrition.This paper indicates the transformation of FGD gypsum into α-HH could be effectively promoted by regulating FGD gypsum particle size. | Hailu Fu Caiyun Jia Qiaoshan Chen Xueting Cao Xiaomin Zhang | 2018 | Particuology2018，16，5： | 5 |
| 15 | DEVELOPMENT OF COMPUTER SIMULATION SOFTWAREON PHASE TRANSFORMATION DURING QUENCHING显示文摘A computer software to simulate the phase transformation during quenching is designed based on Avrami equation and Scheil additivity principle of incubation period. The isothermal transformation diagrams of supercooled austenite are described by cubic spline functions. This software is possess of a good graphic interface of Windows style, can simulate the whole process in austenite decomposition during continuous cooling. If the cooling rate was given, the fraction of various microstructures transformed of austenite decomposition during continuous cooling at any temperature can be calculated. The simulation results are checked with the quenching experiment of 45 steel. The results indicate that the simulation results are comparatively close to the experimental results. | L. Chen, W. Xia and X. J. Chen Department of Materials Science and Engineering, Nanchang Institute of Aeronautical Technology, Nanchang 330034, China | 2000 | Acta Metallurgica Sinica(English Letters)2000，13，2： | 5 |
| 16 | Composition and phase structure dependence of mechanical and magnetic properties for AlCoCuFeNi_x high entropy alloys显示文摘In this study, the effects of composition and phase constitution on the mechanical properties and magnetic performance of AlCoCuFeNix(x = 0.5, 0.8, 1.0, 1.5, 2.0, 3.0 in molar ratio) high entropy alloys(HEAs)were investigated. The results show that Ni element could lead to the evolution from face centered cubic(FCC), body centered cubic(BCC) and ordered BCC coexisting phase structure to a single FCC phase. The change of phase constitution enhances the plasticity but reduces the hardness and strength. One of the interesting points is the excellent soft magnetic properties of AlCoCuFeNixHEAs. Soft magnetic performance is dependent on composition and phase transition. AlCoCuFeNi1.5 alloy, achieving a better balance of mechanical and magnetic properties, could be applied as structure materials and soft magnetic materials(SMMs). High Curie temperature(>900 K) and strong phase stability below 1350 K of AlCoCuFeNi0.5 alloy confirm its practicability in a high-temperature environment. Atomic size difference(δ) is utilized as the critical parameter to explain the lattice strain and phase transformation induced by Ni addition. | Cong Liu Wenyi Peng C.S. Jiang Hongmin Guo Jun Tao Xiaohua Deng Zhaoxia Chen | 2019 | Journal of Materials Science & Technology2019，35，6： | 5 |
| 17 | Two-dimensional cellular automaton model for simulating structural evolution of binary alloys during solidification | 张林 张彩碚 | 2006 | Transactions of Nonferrous Metals Society of China2006，7，6： | 4 |
| 18 | DSC STUDY OF MARTENSITIC TRANSFORMATION KINETICS IN A Cu-Zn-Al-Mn-Ni SHAPE MEMORY ALLOY显示文摘DSCSTUDYOFMARTENSITICTRANSFORMATIONKINETICSINACu-Zn-Al-Mn-NiSHAPEMEMORYALLOYGENGGuili;BAIYujun;PENGQifeng(InstituteforMateria... | GENG Guili BAI Yujun PENG Qifeng(Institute for Materials Engineering,Shandong University of Technology,Jinan 250014,China) | 1996 | Acta Metallurgica Sinica(English Letters)1996，9，1： | 4 |
| 19 | Modeling and Simulation of Iron-Carbon Phase Transformation During Tempering of Steel显示文摘Tempering is final process used in heat treatment of steel components.It is important to improve the toughness and ductility of the quenched steel without a great loss of the hardness and strength.However,the traditional tempering process is hard to satisfy requirements of combination mechanical properties with low cost.A quantitative model is developed to simulate the micro-structural evolution during tempering process of carbon steel by modifying the previous Ju and Inoue's model.The model takes into account tempering parameters,carbon content and morphology for iron-carbon phases.Segregation of carbon atoms,precipitation of transition carbides(ε-carbide),decomposition of retained austenite and precipitation of cementite can be predicted respectively.The precipitation of carbides is modeled by considering the competitive precipitations ofε-carbide and cementite.The kinetics of decomposition of retained austenite into ferrite and cementite is depicted by the modified Avrami equation.To validate the model,it is applied to simulate the tempering process of the as-quenched plain carbon steel.The volume fractions of iron-carbon phase are calculated at different tempering temperature and time.It is indicated that tempering time has greater effect on the volume fraction of carbides at high temperature stage.The calculated results are reasonable consistent with the theoretical descriptions. | Dong-ying Ju1,Xiao-hu Deng 2 1Department of Mechanical Engineering,Saitama Institute of Technology,Saitama,Japan 2 Advanced Science Research Laboratory,Saitama Institute of Technology,Saitama,Japan | 2012 | 稀有金属材料与工程2012，41，S1： | 4 |
| 20 | Exploitation of shape memory alloy actuator using resistance feedback control and its development | Hiroki CHO Takaei YAMAMOTO Yuji TAKEDA Akihiko SUZUKI Toshio SAKUMA | 2010 | Progress in Natural Science:Materials International2010，20，1： | 3 |
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