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A simple calculation model for thermodynamic equilibrium information between precipitation and matrix

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Journal of Iron and Steel Research(International) 2018年第11期25卷 1156-1162页

作者： Yong Yang Tian-rui Li Tao Jia Zhao-dong Wang State Key Laboratory of Rolling and Automation Northeastern UniversityShenyang 110819LiaoningChina

A simple theoretical model was developed to predict equilibrium between precipitate and matrix in a multicomponent microalloyed steel.The solute concentration in the matrix,the composition and the volume fraction of the precipitated second phases,and the reduction in critical precipitation temperature of aln induced by carbonitride were quantified by the proposed thermodynamic model.The results predicted by the developed model and those by other approaches are in a good agreement.The main advantages of this model over the existing models are that the process of formulation derivation is simple and the model can be easily solved by a personal program.

关键词： aln precipitation Carbonitride Thermodynamic model Phase equilibrium

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aln陶瓷烧结技术及性能优化研究进展

耐火材料 2022年第2期56卷 180-184页

作者：王露露马北越刘春明邓承继于景坤东北大学材料科学与工程学院辽宁沈阳110819 东北大学冶金学院辽宁沈阳110819 武汉科技大学省部共建耐火材料与冶金国家重点实验室湖北武汉430081

微电子技术的飞速发展对芯片基板和封装材料性能的要求越来越高。aln陶瓷因其高热导率、高强度、线膨胀系数与硅接近、介电常数小、耐高温和耐腐蚀性能优异而被用作芯片基板和封装材料。主要从烧结技术和烧结助剂对aln陶瓷性能影响方面... 详细信息

微电子技术的飞速发展对芯片基板和封装材料性能的要求越来越高。aln陶瓷因其高热导率、高强度、线膨胀系数与硅接近、介电常数小、耐高温和耐腐蚀性能优异而被用作芯片基板和封装材料。主要从烧结技术和烧结助剂对aln陶瓷性能影响方面综述了aln陶瓷的研究进展,并指出了aln陶瓷在制备及应用过程中存在的问题,展望了aln陶瓷的发展趋势。

关键词： aln 烧结技术烧结助剂

Austenite grain growth of medium-carbon alloy steel with aluminum additions during heating process

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International Journal of Minerals,Metallurgy and Materials 2019年第3期26卷 282-290页

作者： Zi-yi Liu Yan-ping Bao Min Wang Xin Li Fan-zheng Zeng State key Laboratory of Advanced Metallurgy University of Science and Technology Beijing Xiangtan Iron & Steel Co. Ltd.of Hunan Valin

In this study, the effects of heating temperature(850–1100°C) and holding time(30–150 min) on the grain growth behavior of austenite in medium-carbon alloy steel were investigated by conducting experiments. The abnormal grain growth and mixed grain structure phenomenon are explained using an equilibrium precipitation phase diagram calculated by Thermo-Calc software package. The Al N particles were observed by field-emission scanning electron microscopy(FESEM), and the amount of aln precipitations was detected by electron probe microanalysis(EPMA). Based on the research results, it was found that the average grain size of austenite in the test steel increased continuously with the increase of temperature and holding time. Furthermore, the abnormal growth of austenite occurred in the test steel at 950°C, and the heating temperature affected the austenite grain size more significantly. In addition, the decline in the amount of aln second-phase particle in the test steel, which weakened the "pinning" effect on austenite grain boundaries, resulted in abnormal growth and the development of mixed austenite grain structures. The prediction model for describing the austenite grain growth of medium-carbon alloy steel during heating was established by regression analysis of the experimental data, and the model was verified to be highly accurate.

关键词： alloy steel austenite grain aln growth model

Strain effect on the electronic properties of III-nitride nanosheets:Ab-initio study

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Science China(Technological Sciences) 2018年第4期61卷 535-541页

作者： GHASEMZADEH Farzaneh KANJOURI Faramarz Faculty of Physics Kharazmi University

In this study the structural and electronic properties of III-nitride monolayers XN(X=B, Al, Ga and In) under different percentages of homogeneous and shear strain are investigated using the full potential linearized augmented plane wave within the density functional theory. Geometry optimizations indicate that GaN and InN monolayers get buckled under compressive strain.Our calculations show that the free-strains of these four monolayers have an indirect band gap. By applying compressive biaxial strain, a transition from indirect to direct band gap occurs for GaN and InN, while the character of band gap for BN and aln is not changed. Under tensile strain, only BN monolayer behaves as direct band gap semiconductor. In addition, when the shear strain is applied, only InN undergoes an indirect to direct band gap transition. Furthermore, the variations of band gap versus strain for III-nitride monolayers have been calculated. When a homogeneous uniform strain, in the range of [.10%, +10%], is applied to the monolayers, the band gap can be tuned for from 3.92 eV to 4.58 eV for BN, from 1.67 eV to 3.46 eV for aln, from0.24 eV to 2.79 eV for GaN and from 0.60 eV to 0.90 eV for InN.

关键词： Ab-initio 电子性质 III 氮化物学习 aln eV 单层

Sintering behavior of aluminum nitride powder prepared by self-propagating high-temperature synthesis method

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Rare Metals 2018年第12期37卷 1091-1095页

作者： Liang Qiao Shu-Wen Chen Li-Qiang Jiang Kazuo Shinozaki Sheng-Lei Che Research Center of Magnetic and Electronic Materials College of Materials Science and Engineering Zhejiang University of Technology Department of Metallurgy and Ceramics Science Tokyo Institute of Technology

Fully dense aluminum nitride(AIN) ceramics were synthesized by self-propagating high-temperature synthesis(SHS) method using AIN powder as raw material with Y2O3additive. The sintering behavior was studied at different sintering temperatures and additive contents. The change of phase compositions, secondary phase distributions and grain morphologies during sintering process were investigated. It is shown that fully dense ceramics using AIN powder prepared by SHS method can be obtained when the sintering temperature is above 1830 ℃. Both Y2O3content and sintering temperature have an important influence on the formation of Y-Al-O phase and grain shape. When Y2O3content is identified, the grain morphology converts from polyhedron into sphere-like shape with the rise of sintering temperature. At a certain sintering temperature,the grain size decreases with the increase in Y2O3content. The influencing mechanisms of different YAl-O secondary phases and sintering temperatures on the grain size and morphology were also discussed based on the experimental results.

关键词： Self-propagating high-temperature synthesis aln Secondary phase Liquid-phase sintering

Effects of aln on the densification and mechanical properties of pressureless-sintered SiC ceramics

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Progress in Natural Science:Materials International 2016年第1期26卷 90-96页

作者： Qisong Li Yujun Zhang Hongyu Gong Haibin Sun Yanxia Zhai Weiya Zhu Jie Jing Key Laboratory for Liquid–solid Structural Evolution & Processing of Materials of Ministry of Education Shandong University Key Laboratory of Special Functional Aggregated Materials Ministry of Education Shandong University School of Materials and Chemical Engineering Zhongyuan University of Technology Shandong Baona New Materials Co. Ltd.

In the present work, Si C ceramics was fabricated with Al N using B;C and C as sintering aids by a solid-state pressureless-sintered method. The effects of Al N contents on the densification, mechanical properties, phase compositions, and microstructure evolutions of as-obtained Si C ceramics were thoroughly investigated. Al N was found to promote further densification of the Si C ceramics due to its evaporation over 1800 °C,transportation, and solidification in the pores resulted from Si C grain coarsening. The highest relative density of 99.65% was achieved for Si C sample with 15.0 wt% Al N by the pressureless-sintered method at 2130 °C for 1 h in Ar atmosphere. Furthermore, the fracture mechanism for Si C ceramics containing Al N tended to transfer from single transgranular fracture mode to both transgranular fracture and intergranular fracture modes when the sample with 30.0 wt% Al N sintered at 1900 °C for 1 h in Ar. Also, Si C ceramics with 30.0 wt% Al N exhibited the highest fracture toughness of 5.23 MPa m;when sintered at 1900 °C.

关键词： SiC ceramics aln Densification Pressure-less sintering

aln变质对Al-4Si-0.45Mg合金性能的影响

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特种铸造及有色合金 2023年第2期43卷 236-240页

作者：张浩毛红奎刘洪斌闫志义曹美文马瑞林肖璐王宇中北大学材料科学与工程学院山西柴油机工业有限责任公司

在亚共晶Al-4Si-0.45Mg合金中添加微量aln,以改善合金的显微组织并提高其力学性能和导热性能。结果表明,未添加Sr和aln的合金,其抗拉强度为167.3 MPa,伸长率为10%,热导率为149.5 W/(m·K);添加Sr后的抗拉强度为176.2 MPa,伸长率为20%,... 详细信息

在亚共晶Al-4Si-0.45Mg合金中添加微量aln,以改善合金的显微组织并提高其力学性能和导热性能。结果表明,未添加Sr和aln的合金,其抗拉强度为167.3 MPa,伸长率为10%,热导率为149.5 W/(m·K);添加Sr后的抗拉强度为176.2 MPa,伸长率为20%,热导率为166.8 W/(m·K),抗拉强度和热导率分别提高了5.4%、11.6%;添加aln后的合金抗拉强度为194.8 MPa,伸长率为16%,热导率为170.1 W/(m·K),抗拉强度和热导率分别提高了16.4%、13.8%。力学性能的提高主要与α-Al的晶粒细化、二次枝晶臂间距(SADS)的减小和Si的变质有关。加入Sr和aln后,共晶Si由片状变成块状和球状,Sr变质后共晶Si的尺寸明显减少,且aln变质后共晶Si的平均尺寸更小,说明热导率的提高主要与共晶Si相的形态变化有关。其机制为细小的Si使得电子通道增加,电子散射概率降低,平均自由程增加,从而提高了热导率。

关键词： Al-4Si-0.45Mg合金 Si变质 aln 热导率

In-situ Formed AIN Particulates and TiN Whiskers Mixture Reinforced Al Composite

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Journal of Materials Science & Technology 1996年第5期12卷 365-368页

作者： Chunxiang CUI Renjie WU and Guoding ZHANG (Institute of Composite Materials, Shanghai Jiao Tong University, Shanghai 200030, China) Institute of Composite Materials Shanghai Jiao Tong University Shanghai 200030 China

The TiNw-AINp/Al composite has been successfully fabricated by gas-liquid reaction method in an intensive electromagnetic mixing and casting in an appropriate cooling condition. The as-cast samples of the composite exhibit a homogeneous distribution of TiNw and AINp, and the in situ formed TiN whisker has a mean diameter of 0.5 μm and mean aspect ratio of 5.8~7.5, and the diameter of the AIN particulates is less than 5 μm. TEM observation indicates that there exist some submicron and nanometer sized in situ formed TiNw-AINp in α-Al matrix. The formation mechanism of in situ formed TiNw and AINp is also discussed

关键词： Al TiN AIN aln

Formation of aln Nano Particles Precipitated in St-14 Low Carbon Steel by Micro and Nanoscopic Observations

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Journal of Iron and Steel Research(International) 2014年第9期21卷 886-890页

作者： Amirsalar Khandan Ebrahim Karamian Mojdeh Faghih Allain Bataille Department of Mechanical Engineering Islamic Azad UniversityKhomeinishahr BranchKhomeinishahr 84175119IsfahanIran Department of Materials Engineering Islamic Azad UniversityNajafabad BranchNajafabad ***IsfahanIran Department of Metallurgy Physique Material Transformation UnitUniversity of Lille 1(USTL)F-59655 Villeneuve d'Ascq CedexLilleFrance

In low carbon steels, dissolution and precipitation of the second phases such as carbides and nitrides during annealing cycles can affect the final structure and properties of the materials. The interaction of above processes depends on parameters such as reheating temperature, heating rate, annealing temperature, soaking time and finishing temperature in hot rolling stage before cold rolling. The effects of heating rate and annealing temperature on the microstructure and hardness were investigated. Two heating rates for annealing temperatures of 550, 610 and 720℃ were applied on cold-rolled specimens and St-14 low carbon steel, which were immediately quenched after isothermal annealing. The intercept method was used tO measure average grain sizes. However, resulted microstructures are dif- ferent for the two heating rates. While pancaked structures were observed in specimens annealed with low heating rate, in samples annealed with high heating rate, equiaxed microstructures were observed. Vickers micro-hardness values decreased at all temperatures, which were more significant at higher temperatures. At longer annealing time, signs of increase of hardness values were detected. All results and observations consistently suggest that a precipitati- on process has occurred concurrently with restoration processes during annealing. In addition, the energy dispersive spectroscopy analysis resulted from transmission electron microscopic micrographs have proved that the nano particles precipitated in grain boundaries are aln.

关键词： precipitation nano particle aln low carbon steel microstructure