期刊文献+
共找到1,341篇文章
< 1 2 68 >
每页显示 20 50 100
Modeling Method of C/C-ZrC Composites and Prediction of Equivalent Thermal Conductivity Tensor Based on Asymptotic Homogenization
1
作者 Junpeng Lyu Hai Mei +2 位作者 Liping Zu Lisheng Liu Liangliang Chu 《Computer Modeling in Engineering & Sciences》 SCIE EI 2024年第1期391-410,共20页
This article proposes a modeling method for C/C-ZrC composite materials.According to the superposition of Gaussian random field,the original gray model is obtained,and the threshold segmentation method is used to gene... This article proposes a modeling method for C/C-ZrC composite materials.According to the superposition of Gaussian random field,the original gray model is obtained,and the threshold segmentation method is used to generate the C-ZrC inclusion model.Finally,the fiber structure is added to construct the microstructure of the three-phase plain weave composite.The reconstructed inclusions can meet the randomness of the shape and have a uniform distribution.Using an algorithm based on asymptotic homogenization and finite element method,the equivalent thermal conductivity prediction of the microstructure finite element model was carried out,and the influence of component volume fraction on material thermal properties was explored.The sensitivity of model parameters was studied,including the size,mesh sensitivity,Gaussian complexity,and correlation length of the RVE model,and the optimal calculation model was selected.The results indicate that the volume fraction of the inclusion phase has a significant impact on the equivalent thermal conductivity of the material.As the volume fraction of carbon fiber and ZrC increases,the equivalent thermal conductivity tensor gradually decreases.This model can be used to explore the impact of materialmicrostructure on the results,and numerical simulations have studied the relationship between structure and performance,providing the possibility of designing microstructure based on performance. 展开更多
关键词 3D reconstruction randomheterogeneous media microstructure asymptotic homogenization effective properties
下载PDF
Integrated multi-scale approach combining global homogenization and local refinement for multi-field analysis of high-temperature superconducting composite magnets
2
作者 Hanxiao GUO Peifeng GAO Xingzhe WANG 《Applied Mathematics and Mechanics(English Edition)》 SCIE EI CSCD 2024年第5期747-762,共16页
Second-generation high-temperature superconducting(HTS)conductors,specifically rare earth-barium-copper-oxide(REBCO)coated conductor(CC)tapes,are promising candidates for high-energy and high-field superconducting app... Second-generation high-temperature superconducting(HTS)conductors,specifically rare earth-barium-copper-oxide(REBCO)coated conductor(CC)tapes,are promising candidates for high-energy and high-field superconducting applications.With respect to epoxy-impregnated REBCO composite magnets that comprise multilayer components,the thermomechanical characteristics of each component differ considerably under extremely low temperatures and strong electromagnetic fields.Traditional numerical models include homogenized orthotropic models,which simplify overall field calculation but miss detailed multi-physics aspects,and full refinement(FR)ones that are thorough but computationally demanding.Herein,we propose an extended multi-scale approach for analyzing the multi-field characteristics of an epoxy-impregnated composite magnet assembled by HTS pancake coils.This approach combines a global homogenization(GH)scheme based on the homogenized electromagnetic T-A model,a method for solving Maxwell's equations for superconducting materials based on the current vector potential T and the magnetic field vector potential A,and a homogenized orthotropic thermoelastic model to assess the electromagnetic and thermoelastic properties at the macroscopic scale.We then identify“dangerous regions”at the macroscopic scale and obtain finer details using a local refinement(LR)scheme to capture the responses of each component material in the HTS composite tapes at the mesoscopic scale.The results of the present GH-LR multi-scale approach agree well with those of the FR scheme and the experimental data in the literature,indicating that the present approach is accurate and efficient.The proposed GH-LR multi-scale approach can serve as a valuable tool for evaluating the risk of failure in large-scale HTS composite magnets. 展开更多
关键词 epoxy-impregnated high-temperature superconducting(HTS)magnet multi-scale method global homogenization(GH) local refinement(LR) multi-field analysis
下载PDF
Homogenization Construction of Three-Level Teaching Bases for General Practice Medicine Under the Internet+Model
3
作者 Yu Cai Ge Wu +3 位作者 Yuanyuan Jia Siqi Wang Chang Tian Yu Feng 《Journal of Contemporary Educational Research》 2024年第5期46-52,共7页
With the continuous expansion of medical student enrollment,the number of clinical teaching bases is gradually increasing.However,there are significant differences in clinical teaching management models and teaching l... With the continuous expansion of medical student enrollment,the number of clinical teaching bases is gradually increasing.However,there are significant differences in clinical teaching management models and teaching levels among different bases.Most clinical teaching bases have incomplete teaching management systems,inadequate teaching management institutions,insufficient teaching personnel,and inadequate implementation of teaching rules and regulations.This article combines the construction practice of three-level clinical teaching base of the General Medicine College and the First Affiliated Hospital of Xi’an Medical University.We establish a standardized management system for the three-level clinical teaching base;implement a teaching supervision system and strengthen the monitoring of teaching quality;adopt multiple evaluations to test the effectiveness of clinical teaching implementation;explore the path of homogenization construction of teaching bases in terms of unified teacher training,promoting the development of teacher teaching abilities with equal quality and excellence,and providing a reference for improving the quality of medical talent training. 展开更多
关键词 Clinical teaching base homogenization construction General practice medicine
下载PDF
Microstructural evolution of ultra-high strength Al-Zn-Cu-Mg-Zr alloy containing Sc during homogenization 被引量:11
4
作者 李文斌 潘清林 +2 位作者 肖艳苹 何运斌 刘晓艳 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2011年第10期2127-2133,共7页
The microstructural evolution and composition distribution of an Al-Zn-Cu-Mg-Sc-Zr alloy during homogenization were investigated by optical microscopy(OM),scanning electron microscopy(SEM),energy dispersive spectr... The microstructural evolution and composition distribution of an Al-Zn-Cu-Mg-Sc-Zr alloy during homogenization were investigated by optical microscopy(OM),scanning electron microscopy(SEM),energy dispersive spectrometry(EDS),X-ray diffraction(XRD) and differential scanning calorimetry(DSC).The results show that severe dendritic segregation exists in Al-Zn-Cu-Mg-Sc-Zr alloy ingot.There are a lot of eutectic phases at grain boundary and the distribution of the main elements varies periodically along interdendritic region.The main eutectic phases at grain boundary are Al7Cu2Fe phase and T(Al2Mg3Zn3).The residual phases are dissolved into the matrix gradually during homogenization with increasing temperature and prolonging holding time,which can be described by a constitutive equation in exponential function.The overburnt temperature of the alloy is 473.9 ℃.The optimum parameters of homogenization are 470 ℃ and 24 h,which is consistent with the result of homogenization kinetic analysis. 展开更多
关键词 Al-Zn-Cu-Mg-Sc-Zr alloy homogenization microstructural evolution overburnt temperature homogenization kinetics
下载PDF
Quantitative analysis of homogenization treatment of INCONEL718 superalloy 被引量:14
5
作者 缪竹骏 单爱党 +3 位作者 吴元彪 卢俊 徐文亮 宋洪伟 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2011年第5期1009-1017,共9页
Quantitative analysis was employed to establish reasonable and practical homogenization model of INCONEL718 superalloy. Metallographic method was applied to determining the incipient melting temperature. The result sh... Quantitative analysis was employed to establish reasonable and practical homogenization model of INCONEL718 superalloy. Metallographic method was applied to determining the incipient melting temperature. The result shows that the incipient melting temperature of d406 mm INCONEL718 ingot is situated between 1 170 ℃ and 1 180 ℃. In order to predict the elimination process of Laves phase in quantity, a time and temperature dependent homogenization model was proposed. Among all the elements in the as-cast microstructure, Nb and Ti are the most positive segregated elements. The diffusion coefficients of alloying elements at 1 140 ℃ were obtained by fitting the linear relationship between In δ (δ residual segregation index) and time. The calculation results of diffusion coefficients were compared with other two commercial Nb-bearing superalloys. 展开更多
关键词 INCONEL718 SUPERALLOY homogenization Laves phase SEGREGATION
下载PDF
Microstructural evolution during homogenization of Al-Cu-Li-Mn-Zr-Ti alloy 被引量:17
6
作者 李红英 苏雄杰 +1 位作者 尹浩 黄德胜 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2013年第9期2543-2550,共8页
The microstructure evolution of Al-Cu-Li-Mn-Zr-Ti alloy during homogenization was investigated by optical microscopy (OM), scanning electron microscopy (SEM), energy dispersive X-ray spectrometry (EDX), and diff... The microstructure evolution of Al-Cu-Li-Mn-Zr-Ti alloy during homogenization was investigated by optical microscopy (OM), scanning electron microscopy (SEM), energy dispersive X-ray spectrometry (EDX), and differential scanning calorimeter (DSC) methods. The results show that severe dendritic segregation exists in the experimental alloy ingot. Numerous eutectic phases can be observed in the grain boundary, and the distribution of the main elements along the interdendritic region varies periodically. The main secondary phase is Al2Cu. The overburnt temperature of the alloy is 520 °C. The second phases are gradually dissolved into the matrix, and the grain boundaries become spare and thin during homogenization with increasing temperature or prolonging holding time. Homogenization can be described by a constitutive equation in exponential function. The suitable homogenization treatment for the alloy is (510 °C, 18 h), which agrees well with the results of homogenization kinetic analysis. 展开更多
关键词 Al-Cu-Li-Mn-Zr-Ti alloy homogenization microstructure kinetics
下载PDF
Microstructure of Al-Zn-Mg-Cu-Zr-0.5Er alloy under as-cast and homogenization conditions 被引量:12
7
作者 王少华 孟令刚 +4 位作者 杨守杰 房灿峰 郝海 戴圣龙 张兴国 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2011年第7期1449-1454,共6页
The billets of Al-Zn-Mg-Cu-Zr and Al-Zn-Mg-Cu-Zr-0.5Er alloys were prepared by semi-continuous direct chill casting (DCC).The effects of trace Er on microstructure of Al-Zn-Mg-Cu-Zr alloy under as-cast and homogeniz... The billets of Al-Zn-Mg-Cu-Zr and Al-Zn-Mg-Cu-Zr-0.5Er alloys were prepared by semi-continuous direct chill casting (DCC).The effects of trace Er on microstructure of Al-Zn-Mg-Cu-Zr alloy under as-cast and homogenization conditions were studied.The results show that the grain morphology is large dendritic structure and the grain size increases obviously by the addition of 0.5% Er.Moreover,most of Er element in the alloy segregates at grain boundary during solidification,resulting in ternary Al8Cu4Er phase.After homogenization,most of the MgZn2 phase at grain boundary has dissolved back to Al matrix in the two alloys.In the Er-containing alloy,the dissolution temperature of Al8Cu4Er phase is about 575 °C.Therefore,the homogenization treatment cannot eliminate Al8Cu4Er phase validity. 展开更多
关键词 Al-Zn-Mg-Cu-Zr alloy Er Al8Cu4Er phase homogenization MICROSTRUCTURE
下载PDF
Homogenization on microstructure and mechanical properties of 2A50 aluminum alloy prepared by liquid forging 被引量:11
8
作者 杜之明 陈刚 +5 位作者 韩飞 曹广祥 柳君 李宏伟 张新 谢水生 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2011年第11期2384-2390,共7页
The homogenization on microstructure and mechanical properties of 2A50 aluminum alloy prepared by liquid forging was investigated.Wheel hubs were produced using direct and compound loading.The results show that the mi... The homogenization on microstructure and mechanical properties of 2A50 aluminum alloy prepared by liquid forging was investigated.Wheel hubs were produced using direct and compound loading.The results show that the microstructure and mechanical properties are inhomogeneous in direct forged samples.The microstructure of the wall is coarser than that of the base,and the mechanical properties are lower and some defects are detected at the wheel corner.Using compound loading,the microstructure and mechanical properties of the wall are improved evidently.With increasing feeding amount,the microstructure and mechanical properties become more homogeneous.The defects disappear when the feeding amount is 4 mm.The forged wheel hubs could obtain fine and homogeneous microstructure with grain size of 20-30 μm,tensile strength of 355 MPa and elongation of 10% when the feeding amount is 10 mm.The microstructure and mechanical properties of liquid forged workpieces could be controlled and homogenized using compound loading. 展开更多
关键词 homogenization aluminum alloy liquid forging compound loading
下载PDF
Microstructural evolution of Mg, Ag and Zn micro-alloyed Al-Cu-Li alloy during homogenization 被引量:11
9
作者 刘晴 朱瑞华 +4 位作者 李劲风 陈永来 张绪虎 张龙 郑子樵 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2016年第3期607-619,共13页
The microstructural evolution of a Mg, Ag and Zn micro-alloyed Al?3.8Cu?1.28Li (mass fraction, %) alloy ingot during two-step homogenization was examined in detail by optical microscopy (OM), differential scanning cal... The microstructural evolution of a Mg, Ag and Zn micro-alloyed Al?3.8Cu?1.28Li (mass fraction, %) alloy ingot during two-step homogenization was examined in detail by optical microscopy (OM), differential scanning calorimetry (DSC), electron probe micro-analysis (EPMA) and X-ray diffraction (XRD) methods. The results show that severe dendritic segregation exists in the as-cast ingot. There are many secondary phases, includingTB(Al7Cu4Li),θ(Al2Cu),R(Al5CuLi3) andS(Al2CuMg) phases, and a small amount of (Mg+Ag+Zn)-containing and AlCuFeMn phases. The fractions of intermetallic phases decrease sharply after 2 h of second-step homogenization. By prolonging the second-step homogenization time, theTB,θ,R,S and (Mg+Ag+Zn)-containing phases completely dissolve into the matrix. The dendritic segregation is eliminated, and the homogenization kinetics can be described by a constitutive equation in exponential function. However, it seems that the AlCuFeMn phase is separated into Al7Cu2Fe and AlCuMn phases, and the size of Al7Cu2Fe phase exhibits nearly no change when the second-step homogenization time is longer than 2 h. 展开更多
关键词 Al-Cu-Li alloy homogenization microstructural evolution Al_7Cu_2Fe AlCuMn
下载PDF
Effect of homogenization time on quench sensitivity of 7085 aluminum alloy 被引量:11
10
作者 郑玉林 李承波 +2 位作者 刘胜胆 邓运来 张新明 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2014年第7期2275-2281,共7页
The effect of homogenization time on quench sensitivity of a cast 7085 aluminum alloy was investigated by means of end-quenching test, optical microscope (OM), scanning electron microscope (SEM) and transmission e... The effect of homogenization time on quench sensitivity of a cast 7085 aluminum alloy was investigated by means of end-quenching test, optical microscope (OM), scanning electron microscope (SEM) and transmission electron microscope (TEM). The results show that with the increase of homogenization time from 48 h to 384 h, quench sensitivity increased slightly as the largest difference in the hardness was increased from 5.2% to 6.9% in the end-quenched and aged specimens. Prolonging homogenization had little effect on the grain structure, but improved the dissolution of soluble T phase and resulted in larger Al3Zr dispersoids with a low number density. Some small quench-induced η phase particles on Al3Zr dispersoids were observed inside grains during slow quenching, which decreased hardness after subsequent aging. The change in the character of Al3Zr dispersoids exerted slight influence on quench sensitivity. 展开更多
关键词 7085 aluminum alloy homogenization end quenching quench sensitivity Al3Zr dispersoids equilibrium η phase
下载PDF
Tensile behavior of 3104 aluminum alloy processed by homogenization and cryogenic treatment 被引量:9
11
作者 张文达 白培康 +3 位作者 杨晶 徐宏 党惊知 杜振民 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2014年第8期2453-2458,共6页
The mechanical properties of 3104 aluminum alloy processed by different combinations of cryogenic and homogenization treatments were studied. The 3104 aluminum alloy processed by the cryogenic treatment followed by ho... The mechanical properties of 3104 aluminum alloy processed by different combinations of cryogenic and homogenization treatments were studied. The 3104 aluminum alloy processed by the cryogenic treatment followed by homogenization exhibited an enhancement in the tensile strength, yield strength, and elongation by 29%, 41%, and 11%, respectively, as compared with a sample processed by the conventional homogenization treatment. The stress-strain curve of the sample processed by the homogenization treatment exhibited the Portevin-Le Chatelier effect, whereas the sample processed by the cryogenic treatment did not. Further, the cryogenic treatment could accelerate the precipitation of secondary phase particles for the sample processed by a deep cryogenic treatment, followed by a homogenization treatment, which enhanced the dislocation pinning effect of the solvent atoms and thus improved the critical strain. 展开更多
关键词 DEFORMATION homogenization cryogenic treatment MICROSTRUCTURE Portevin–Le Chatelier effect
下载PDF
Intermetallic phase evolution of 5059 aluminum alloy during homogenization 被引量:9
12
作者 蒋海春 叶凌英 +3 位作者 张新明 顾刚 张盼 吴豫陇 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2013年第12期3553-3560,共8页
Intermetallic phase evolution of 5059 aluminum alloy during homogenization was investigated by means of optical microscopy (OM), scanning electron microscopy (SEM), transmission electron microscopy (TEM), energy... Intermetallic phase evolution of 5059 aluminum alloy during homogenization was investigated by means of optical microscopy (OM), scanning electron microscopy (SEM), transmission electron microscopy (TEM), energy dispersive spectrometry (EDS), differential scanning calorimetry (DSC) and X-ray diffraction analysis (XRD). The results show that severe dendritic segregation exists in as-cast alloy. The dissolvable intermetallic phases in as-cast alloy consist of Zn-and Cu-rich non-equilibriumβ(Al3Mg2) phase, Fe-rich eutectic Al6Mn phase and equilibrium Mg2Si phase. During the homogenization, Zn- and Cu-rich non-equilibrium β (Al3Mg2) phase, Fe-rich eutectic Al6Mn phase and equilibrium Mg2Si gradually dissolve into matrix. Fine dispersed β(Al3Mg2) particles and rod-shaped Al6Mn particles form in the Al matrix after homogenization. The proper homogenization processing is at 450 °C for 24 h, which is consistent with the results of homogenizing kinetic analysis. 展开更多
关键词 intermetallic phase 5059 aluminum alloy homogenization MICROSTRUCTURE EVOLUTION
下载PDF
Microstructural evolution of Al-Zn-Mg-Zr alloy with trace amount of Sc during homogenization treatment 被引量:7
13
作者 李波 潘清林 +2 位作者 史运嘉 李晨 尹志民 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2013年第12期3568-3574,共7页
The microstructural evolution of Al-Zn-Mg-Zr alloy with trace amount of Sc during homogenization treatment was studied by means of metallographic analysis, scanning electron microscopy (SEM), energy dispersive X-ray... The microstructural evolution of Al-Zn-Mg-Zr alloy with trace amount of Sc during homogenization treatment was studied by means of metallographic analysis, scanning electron microscopy (SEM), energy dispersive X-ray (EDX) and differential scanning calorimetry (DSC). The results show that serious dendritic segregation exists in studied alloy ingot. There are many eutectic phases with low melting-point at grain boundary and the distribution of main elements along interdendritic region varies periodically. Elements Zn, Mg and Cu distribute unevenly from grain boundary to the inside of alloy. With increasing the homogenization temperature or prolonging the holding time, the residual phases are dissolved into matrix α(Al) gradually during homogenization treatment, all elements become more homogenized. The overburnt temperature of studied alloy is 476.7 °C. When homogenization temperature increases to 480 °C, some spherical phases and redissolved triangular constituents at grain boundaries can be easily observed. Combined with microstructural evolution and differential scanning calorimeter, the optimum homogenization parameter is at 470 °C for 24 h. 展开更多
关键词 Al-Zn-Mg-Sc-Zr alloy dendritic segregation homogenization residual phases overburnt temperature microstructural evolution
下载PDF
Effect of homogenization treatment on microstructure and mechanical properties of DC cast 7X50 aluminum alloy 被引量:12
14
作者 丛福官 赵刚 +2 位作者 姜锋 田昵 李瑞峰 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2015年第4期1027-1034,共8页
The evolution of the eutectic structures in the as-cast and homogenized 7X50 aluminum alloys was studied by scanning electron microscopy(SEM), transmission electron microscopy(TEM), energy dispersive spectrometer(EDS)... The evolution of the eutectic structures in the as-cast and homogenized 7X50 aluminum alloys was studied by scanning electron microscopy(SEM), transmission electron microscopy(TEM), energy dispersive spectrometer(EDS), differential scanning calorimetry(DSC), X-ray diffraction(XRD) and tensile test. The results show that the main phases are S(Al2CuMg), T(Al2Mg3Zn3) and Mg Zn2, with a small amount of Al7Cu2 Fe and Al3 Zr in the as-cast 7X50 alloy. The volume fraction of the dendritic-network structure and residual phase decreases gradually during the homogenization. After homogenization at 470 °C for 24 h and then 482 °C for 12 h, the T(Al2Mg3Zn3) phase disappears and minimal S(Al2CuMg) phase remains, while almost no change has happened for Al7Cu2 Fe. There is a strong endothermic peak at 477.8 °C in the DSC curve of as-cast alloy. A new endothermic peak appears at 487.5 °C for the sample homogenized at 470 °C for 1 h. However, this endothermic peak disappears after being homogenized at 482 °C for 24 h. The T(Al2Mg3Zn3) phase cannot be observed by XRD, which is consistent with that T phase is the associated one of S(Al2CuMg) phase and Mg Zn2 phase. The volume fraction of recrystallized grains is substantially less in the plate with pre-homogenization treatment. The strength and fracture toughness of the plate with pre-homogenization treatment are about 15 MPa and 3.3 MPa·m1/2 higher than those of the material with conventional homogenization treatment. 展开更多
关键词 7X50 aluminum alloy microstructural evolution homogenization residual phase RECRYSTALLIZATION
下载PDF
Effect of one-step and two-step homogenization treatments on distribution of Al_3Zr dispersoids in commercial AA7150 aluminium alloy 被引量:10
15
作者 吕新宇 郭二军 +1 位作者 Paul ROMETSCH 王立娟 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2012年第11期2645-2651,共7页
Semi-quantitative electron probe microanalysis (EPMA) mapping, scanning electron microscopy (SEM) and transmission electron microscopy (TEM) were employed to study the effect of one-step and two-step treatments ... Semi-quantitative electron probe microanalysis (EPMA) mapping, scanning electron microscopy (SEM) and transmission electron microscopy (TEM) were employed to study the effect of one-step and two-step treatments on the Zr distribution and Al3Zr dispersoid characteristics in as-cast commercial AA7150 aluminum alloy. It is shown that the Zr concentration in the dendrite centre regions is higher than that near the dendrite edges in the as-cast condition, and that homogenization at 460 °C for 20 h is insufficient to remove these concentration gradients. After homogenizing at 460-480 °C, a high number density of larger dispersoids can be observed in dendrite centre regions but not near dendrite edges. Furthermore, the dispersoid size increases with increasing the temperature during both one-step and two-step homogenization treatments. 展开更多
关键词 7xxx alloy AA7150 alloy homogenization recrystallization Al3Zr dispersoids concentration gradient
下载PDF
Effects of P and B addition on as-cast microstructure and homogenization parameter of Inconel 718 alloy 被引量:4
16
作者 缪竹骏 单爱党 +4 位作者 吴元彪 卢俊 胡莹 刘俊亮 宋洪伟 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2012年第2期318-323,共6页
The effects of phosphorus and boron addition on the as-cast microstructure and homogenization parameters of Inconel 718 were studied. The results indicate that the addition of phosphorus and boron promotes the formati... The effects of phosphorus and boron addition on the as-cast microstructure and homogenization parameters of Inconel 718 were studied. The results indicate that the addition of phosphorus and boron promotes the formation of blocky Laves phase. Due to the strong segregation behavior of boron in the final residual liquid, a low melting B-bearing phase enriched in Nb, Mo and Cr is observed. According to the differential scanning calorimeter results and electron probe micro-analysis characterization, the solidification sequence of Inconel 718 with phosphorus and boron addition in best combination is determined as L→L+γ→L+γ+MC→L+γ+MC+Laves→γ+MC+Laves+MC+Laves+B-bearing phase. Accordingly, the homogenization temperature is recommended to be adjusted at least 40°C lower than that of standard Inconel 718 due to the existence of low melting B-bearing phase. 展开更多
关键词 P B Inconel 718 alloy SOLIDIFICATION microstructure homogenization
下载PDF
Evolution of secondary phases and properties of 7B04 aluminum alloy during DC homogenization 被引量:4
17
作者 何立子 贾品峰 +1 位作者 张林 崔建忠 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2016年第2期319-327,共9页
The effects of the direct current (DC) on the evolutions of hardness and morphology of the secondary phases in 7B04 aluminum alloy homogenized at 380?465 ℃ for 2 h were investigated in detail by electric conductiv... The effects of the direct current (DC) on the evolutions of hardness and morphology of the secondary phases in 7B04 aluminum alloy homogenized at 380?465 ℃ for 2 h were investigated in detail by electric conductivity measurement, hardness test, X-ray diffraction analysis, field emission scanning electron microscopy and energy dispersive spectrometry. The results show that with increasing temperature from 380 to 465 ℃, the electric conductivity of normal homogenized sample decreases from 34.9%IACS to 28.7%IACS, the hardness increases from HV 96 to HV 146, and the area fraction of secondary phase reduces from 4.5% to 1.89%. While, DC homogenized sample has a higher hardness, a lower electric conductivity and a smaller area fraction of secondary phases at the same temperature. The DC enhances the homogenization process by promoting the diffusibility of the solute atoms and the mobility of vacancy. 展开更多
关键词 7B04 aluminum alloy direct current homogenization HARDNESS secondary phase elemental diffusion
下载PDF
Microstructural evolution of Al-0.66Mg-0.85Si alloy during homogenization 被引量:2
18
作者 闫丽珍 张永安 +4 位作者 李锡武 李志辉 王锋 刘红伟 熊柏青 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2014年第4期939-945,共7页
The microstructural evolution of Al-0.66Mg-0.85Si alloy was investigated by optical microscopy (OM), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and differential scanning calorimet... The microstructural evolution of Al-0.66Mg-0.85Si alloy was investigated by optical microscopy (OM), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and differential scanning calorimetry (DSC). The as-cast microstructure is typical dendritical structure, consisting of α(Al), Al(FeMn)Si, Mg2Si, AlCuMgSi and Si phases. The electron diffraction analyses indicate that the Al(FeMn)Si phase is Al15(FeMn)3Si2 and the AlCuMgSi phase is Q(Al1.9CuMg4.1Si3.3). There are two kinds of Mg2Si phases in the as-cast microstructure. One is formed in the casting process, and the other is formed in the cooling process after casting process is finished. The phases have different crystal structures. After homogenization treatment at 545 ℃ for 20 h, Mg2Si, Si and Q intermetallic compounds are dissolved into matrix completely, and the remaining phases are α(Al) and Al15(FeMn)3Si2. The size of Al15(FeMn)3Si2 phase is decreased, and the phase is spheroidized and distributes along grain boundary discontinuously. The Zn-containing phases are not found during solidification and homogenization process. 展开更多
关键词 Al-Mg-Si alloy microstructural evolution homogenization intermetallic compound
下载PDF
Homogenization of twin-roll cast A8006 alloy 被引量:2
19
作者 陈忠伟 李士顺 赵静 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2012年第6期1280-1285,共6页
Microstructure and hardness of twin-roll casting (TRC) process and direct-chill casting (DC) for A8006 alloy with and without homogenization were investigated by means of scanning electron microscopy (SEM), X-ra... Microstructure and hardness of twin-roll casting (TRC) process and direct-chill casting (DC) for A8006 alloy with and without homogenization were investigated by means of scanning electron microscopy (SEM), X-ray diffraction analysis and Vickers hardness measurement. The results show that the eutectic phase of the homogenized TRC alloy becomes fine as the microstructure of the as-cast TRC alloy is refined. The short rodlike eutectic phase of the as-cast TRC alloy is dispersed homogeneously, which is similar to the morphology of eutectic phase of the homogenized DC alloy. After homogenization, elements Fe and Mn in DC and TRC alloys are diffused from eutectic phase to A1 matrix, resulting in the decrease of microhardness. The formability of the as-cast TRC alloy is superior to that of the homogenized DC alloy. For TRC A8006 alloy, the homogenizing cycle can be removed from the subsequent processing. 展开更多
关键词 A8006 alloy twin-roll casting homogenization MICROSTRUCTURE
下载PDF
Microstructural evolution of 2026 aluminum alloy during homogenization 被引量:8
20
作者 JIANG Ding-bang PAN Qing-lin +2 位作者 HUANG Zhi-qi HU Quan LIU Zhi-ming 《Journal of Central South University》 SCIE EI CAS CSCD 2018年第3期490-498,共9页
The microstructural evolution of 2026 aluminum alloy during homogenization treatment was investigated by optical microscopy(OM),scanning electron microscopy(SEM),energy dispersive X-ray spectrometry(EDS),differential ... The microstructural evolution of 2026 aluminum alloy during homogenization treatment was investigated by optical microscopy(OM),scanning electron microscopy(SEM),energy dispersive X-ray spectrometry(EDS),differential scanning calorimetry(DSC)and X-ray diffraction(XRD).The results show that severe dendritic segregation exists in the as-cast 2026 alloy and the main secondary phases at grain boundary are S(Al2CuMg)andθ(Al2Cu)phases.Elements Cu,Mg and Mn distribute unevenly from grain boundary to the inside of as-cast alloy.With the increase of homogenization temperature or the prolongation of holding time,the residual phases gradually dissolve into the matrixα(Al)and all the elements become more homogenized.According to the results of microstructural evolution,differential scanning calorimetry and X-ray diffraction,the optimum homogenization parameter is at 490°C for 24 h,which is consistent with the result of homogenization kinetic analysis. 展开更多
关键词 2026 aluminum alloy dendritic segregation homogenization microstructure evolution homogenization kinetics
下载PDF
上一页 1 2 68 下一页 到第
使用帮助 返回顶部