Fe—Mn—Cr高碳四元合金马氏体相变热力学计算

选取三种热力学模型（规则溶液，ＬＦＧ，ＫＲＣ模型）计算了Ｆｅ－Ｍｎ－Ｃｒ高碳四元合金的马氏体相变驱动力和Ｍ温度，ＫＲＣ模型计算结果与实测值最为接近，ＬＦＧ模型计算结果和实验值相差较大。     

EFFECT OF TRACE ELEMENTS P AND Mn ON THE MICROSTRUCTURE AND HYDROGEN EMBRITTLEMENT OF AN Fe－Ni－Co BASED SUPERALLOY

ＥＦＦＥＣＴＯＦＴＲＡＣＥＥＬＥＭＥＮＴＳＰＡＮＤＭｎＯＮＴＨＥＭＩＣＲＯＳＴＲＵＣＴＵＲＥＡＮＤＨＹＤＲＯＧＥＮＥＭＢＲＩＴＴＬＥＭＥＮＴＯＦＡＮＦｅ－Ｎｉ－ＣｏＢＡＳＥＤＳＵＰＥＲＡＬＬＯＹＷＡＮＧＡｎｃｈｕａｎ;ＹＡＮＧＫｅ;ＦＡＮＣｕｎｇａｎ...     

INFLUENCES OF SULPHUREOUS IMPURITY AND MICROSHRINKAGE ON HAC BEHAVIOR OF SUPER－STRENGTH STEEL

ＩＮＦＬＵＥＮＣＥＳＯＦＳＵＬＰＨＵＲＥＯＵＳＩＭＰＵＲＩＴＹＡＮＤＭＩＣＲＯＳＨＲＩＮＫＡＧＥＯＮＨＡＣＢＥＨＡＶＩＯＲＯＦＳＵＰＥＲ－ＳＴＲＥＮＧＴＨＳＴＥＥＬＳ．Ｋ．Ｈｅ;Ｇ．Ｓ．ＷａｎｇａｎｄＳ．Ｎ．Ｗａｎｇ（Ｂｅｉｊｉｎｇｉｎｓｔｉｔｕｔｅ...     

INVESTIGATIONS ON THE FORMATION OF INITIAL CRACKS IN THERMAL BARRIER COATINGS PREPARED BY EB－PVD

ＩＮＶＥＳＴＩＧＡＴＩＯＮＳＯＮＴＨＥＦＯＲＭＡＴＩＯＮＯＦＩＮＩＴＩＡＬＣＲＡＣＫＳＩＮＴＨＥＲＭＡＬＢＡＲＲＩＥＲＣＯＡＴＩＮＧＳＰＲＥＰＡＲＥＤＢＹＥＢ－ＰＶＤＳ．Ｋ．Ｇｏｎｇ;Ｌ．Ｄｅｎｇ;Ｆ．Ｓ．ＬｉｕａｎｄＨ．Ｂ．Ｘｕ（Ｄｅｐａｒｔｍｅｎ...     

MAGNETIC PROPERTIES AND STRUCTURES OF NANO－CRYSTALLINE Fe－P－C－Mo－Cu－Si ALLOYS

ＭＡＧＮＥＴＩＣＰＲＯＰＥＲＴＩＥＳＡＮＤＳＴＲＵＣＴＵＲＥＳＯＦＮＡＮＯ－ＣＲＹＳＴＡＬＬＩＮＥＦｅ－Ｐ－Ｃ－Ｍｏ－Ｃｕ－ＳｉＡＬＬＯＹＳ￥Ｙ．Ｆ．Ｇａｏ,Ｊ．Ｔａｎ;Ｇ．Ｄ．Ｌｉｕ;Ｃ．Ｌ．Ｚｈａｎｇ;Ｔ．ＬｉｕａｎｄＲ．ＺＭａ（ＲａｐｉｄｌｙＱ...     

ESTABLISHMENT AND VERIFICATION OF MATHEMATICAL MODEL FOR CURRENT LEAKAGE IN BIPOLAR MULTI－COMPARTMENT CELL

ＥＳＴＡＢＬＩＳＨＭＥＮＴＡＮＤＶＥＲＩＦＩＣＡＴＩＯＮＯＦＭＡＴＨＥＭＡＴＩＣＡＬＭＯＤＥＬＦＯＲＣＵＲＲＥＮＴＬＥＡＫＡＧＥＩＮＢＩＰＯＬＡＲＭＵＬＴＩ－ＣＯＭＰＡＲＴＭＥＮＴＣＥＬＬＹａｎｇ；ＪｉａｎｈｏｎｇＺｈａｎｇ；ＱｉｎｇｘｉａｎｇＷａｎ...     

THE ESTABLISHMENT OF CALCULATION FORMULA FOR CASTING－ROLLING FORCE OF VISCOUS FLUID AND THE INFLUENCE OF TECHNOLOGICAL FACTORS

ＴＨＥＥＳＴＡＢＬＩＳＨＭＥＮＴＯＦＣＡＬＣＵＬＡＴＩＯＮＦＯＲＭＵＬＡＦＯＲＣＡＳＴＩＮＧ－ＲＯＬＬＩＮＧＦＯＲＣＥＯＦＶＩＳＣＯＵＳＦＬＵＩＤＡＮＤＴＨＥＩＮＦＬＵＥＮＣＥＯＦＴＥＣＨＮＯＬＯＧＩＣＡＬＦＡＣＴＯＲＳ￥Ｓｕｎ，Ｂｉｎｙｕ；Ｚｈａｎ...     

EFFECTS OF TRACE ELEMENTS ON THE OXIDATION OF LOW SEGREGATION Ni－Cr－Al BASED SUPERALLOYS

ＥＦＦＥＣＴＳＯＦＴＲＡＣＥＥＬＥＭＥＮＴＳＯＮＴＨＥＯＸＩＤＡＴＩＯＮＯＦＬＯＷＳＥＧＲＥＧＡＴＩＯＮＮｉ－Ｃｒ－ＡｌＢＡＳＥＤＳＵＰＥＲＡＬＬＯＹＳ￥Ｗ．Ｓ．Ｈｕ,Ｔ．Ｆ．ＬｉａｎｄＪ．Ｎ．Ｓｈｅｎ（ＳｔａｔｅＫｅｙＬａｂｏｒａｔｏｒｙｏｆＣｏｒ...     

TiC－PHASE DIFFUSION LAYER FORMATION IN TITANIUM CLAD STEEL COMPOSITE HAVING AN INTERMEDIATE LAYER OF α－Fe

ＴｉＣ－ＰＨＡＳＥＤＩＦＦＵＳＩＯＮＬＡＹＥＲＦＯＲＭＡＴＩＯＮＩＮＴＩＴＡＮＩＵＭＣＬＡＤＳＴＥＥＬＣＯＭＰＯＳＩＴＥＨＡＶＩＮＧＡＮＩＮＴＥＲＭＥＤＩＡＴＥＬＡＹＥＲＯＦα－ＦｅＸｉａＣｈａｎｇｑｉｎｇ；ＪｉｎＺｈａｎｐｅｎｇ（Ｄｅｐａｒｔｍｅｎ...     

EFFECT OF MILLING INTENSITY ON STRUCTURAL CHANGES OF MIXED Al－Fe－Ni POWDERS IN MECHANICAL ALLOYING PROCESS

ＥＦＦＥＣＴＯＦＭＩＬＬＩＮＧＩＮＴＥＮＳＩＴＹＯＮＳＴＲＵＣＴＵＲＡＬＣＨＡＮＧＥＳＯＦＭＩＸＥＤＡｌ－Ｆｅ－ＮｉＰＯＷＤＥＲＳＩＮＭＥＣＨＡＮＩＣＡＬＡＬＬＯＹＩＮＧＰＲＯＣＥＳＳ￥ＬｉｕＺｕｙａｎ；ＬｉａｎｇＧｕｏｘｉａｎ；ＷａｎｇＥｒｄｅ（Ｓ...     

微合金钢焊缝针状铁素体相变热力学研究

基于预相变形成奥氏体贫碳区的特点,采用KRC、LFG、MD活度模型和超组元算法,建立了Fe-C-X系微合金焊缝针状铁素体在奥氏体贫碳区切变转变的相变热力学模型,并针对某种微合金钢成分进行了数值计算.结果表明,三种模型具有相同的变化规律,即针状铁素体相变驱动力随着奥氏体贫碳区碳含量的降低而增加,随着相变温度的降低而增加.因此,基于贫碳区的相变模型可获得比以往模型更大的相变驱动力,从热力学角度来讲,针状铁素体在奥氏体贫碳区很可能具有切变转变的相变过程.     

THERMODYNAMICS OF MARTENSITIC TRANSFORMATION IN Fe-Mn-C AND Fe-Ni-C ALLOYS

A Central Atom Model is introduced and the LFG and Hsu models are modified in order toevaluate the driving force for the martensitic transformation in Fe-Mn-C and Fe-Ni-C al-loys.The results show that the relationship between the driving force and the yield strength ofaustenite at Ms temperature,σ_(0.2)~γ/M_s,fits Hsu's formula;ΔG~=2.1σ_(0.2)~γ/M_s+907J/mol.The M_s temperatures of Fe-Mn-C and Fe-Ni-C alloys are also calculated.Thecalculated results are in good agreement with experimental values.     

焊缝针状铁素体中温转变机制的热力学分析

基于预相变形成奥氏体贫碳区的特点,采用KRC活度模型和超组元算法,分别建立了Fe-C-X系微合金焊缝针状铁素体在奥氏体贫碳区扩散和切变转变的两种相变热力学模型,并针对某种微合金钢成分进行了数值计算.结果表明,贫碳区成分不同而表现出不同的相变机制倾向.当奥氏体贫碳区C元素含量较高时,焊缝针状铁素体扩散模型的相变驱动力较大;而贫碳区C元素含量较低时,切变模型的相变驱动力又稍微大些;在贫碳区C元素含量为零的极限条件下,两模型的相变驱动力相等.两种模型的相变驱动力均具有相同的变化规律,即随着奥氏体贫碳区C元素含量的降低而增加,随着相变温度的降低而增加.     

喀土穆炼油厂焦化装置防腐蚀研究及对策

    针对苏丹喀土穆炼油厂焦化装置的腐蚀现状,通过测厚、腐蚀挂片、腐蚀监测和腐蚀产物的分析化验等手段对设备的腐蚀原因及其腐蚀机理进行了分析,提出了防腐工艺、材料升级、腐蚀监测和防腐管理等防腐蚀措施.     

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 采用超组元模型和LFG模型,计算了TRIP钢的碳在γ/α相界面处奥氏体侧的平衡浓度xγ/αC、先共析铁素体相变驱动力ΔGγ→α+γ1和珠光体相变驱动力ΔGγ→α+cem以及相变平衡温度Ae3和Ae1,并分析了不同热变形和化学成分的影响。计算TRIP钢未变形条件下的相变平衡温度Ae3和Ae1与试验值吻合较好,显示了本文相变热力学计算的较高精度。     

Relationship between microstructure and mechanical properties of 5083 aluminum alloy thick plate

The microstructure and mechanical properties of 105 mm thick 5083 aluminum alloy hot rolled plate were investigated by metallurgical microscope, scanning electron microscope and tensile testing machine, and three major characteristic problems in mechanical properties inhomogeneity were explained. The results show that the mechanical properties of the rolled plate are inhomogeneous along the thickness direction. From the surface to the center, the strength shows an inverted “N” shape change and the elongation presents a semi “U” shape change. Several similar structural units composed of long fibrous grains (LFG) and short fibrous grains bands (SFGB) exist in a special layer (Layer 2) adjacent to the surface. This alternating layered distribution of LFG and SFGB is conducive to improving the plasticity by dispersing the plastic deformation concentrated on the boundary line (BL) between them. However, their different deformability will cause the alternation of additional stresses during the hot rolling, leading to the strength reduction. The closer the location to the center of the plate is, the more likely the recovery rather than the recrystallization occurs. This is the possible reason for the unnegligible difference in strength near the central region (Layer 4 and Layer 5).     

Diffusion in the B2-b.c.c. phase of the Al–Fe–Ni system—application of a phenomenological model

A phenomenological model for multicomponent diffusion in B2-b.c.c. ordered phases is applied to the Al–Fe–Ni system. In the model, the activation energy for diffusion is expressed as a function of the degree of ordering, which is evaluated from thermodynamic data. These data are also used to evaluate the thermodynamic factors for diffusion. A CALPHAD-like assessment procedure is applied to the experimental data for diffusion in the B2-b.c.c. phase of the Al–Fe–Ni system. It is shown that the model is capable of representing the experimental data. The diffusivities from the model are used to simulate six different diffusion experiments. The results are compared with experimental data and it is concluded that the model yields satisfactory predictions.     

Modeling micro-end-milling operations. Part III: influence of tool wear

The characteristics of the cutting forces were studied at different usage levels and the analytical model of the micro-end-milling operations was modified to represent the tool wear. A new expression was derived from the model to estimate the remaining tool life from experimental data. The parameters of the model are estimated by using genetic algorithms. The difference between the simulated and experimental cutting force profiles for new and worn tools was less than 8%. The remaining tool life was estimated with typically 10% error from the experimental data. Maximum error was 20%. The introduced analytical model and genetic algorithm-based parameter estimation approach is very convenient for on-line tool wear monitoring without extensive experimental study.     

Microstructural evolution and microsegregation in directional solidification of hypoeutectic Al−Cu alloy: A comparison between experimental data and numerical results obtained via phase-field model

The objective of the work is focused on predictions of microsegregation, solidification speed, dendritic arm spacings and dendrite morphology by phase-field model. The numerical results were compared with experimental data. The experimental values for cooling rates and effective partition coefficient were adopted during calculations. The results of microsegregation through phase-field model show excellent agreement with the experimental data. Such excellent agreement is because cooling rates, effective partition coefficient and back-diffusion of solute are considered in the model. For solidification speed, the calculation results show good agreement with the experimental data. Tertiary dendritic arm spacing calculated with phase-field model is compared with experimental data. The results show good agreement between them. The dendrite arm spacing varies with position because high cooling rates are responsible for the refinement effect on microstructure. Finally, two-dimensional simulation produced a dendrite that is similar to that found in the experiment.     

Improvement of the Prediction Accuracy and Efficiency of Hot Strength of Austenitic Steels with Optimised ANN Training Schemes

The hot strength of austenitic steels of different carbon contents was modelled using an artificial neural network (ANN) model with optimum training data. As training data employed in a traditional neural network model were randomly selected from experimental data, they were not representative and the prediction accuracy and efficiency were therefore significantly affected. In this work, only representatively experimental data were used for training and during the procedure, one tenth of the training data extracted from experiment were used for testing the training model and terminating the modelling. The effects of the carbon con tent on flow stress, peak strains and peak stresses observed from the experiment for both training and test data were accurately represented with the ANN scheme reported in this work.