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Heterogeneous precipitate microstructure in titanium alloys for simultaneous improvement of strength and ductility

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Journal of Materials Science & Technology 2022年第29期124卷 150-163页

作者： Mengyuan Hao Pei li xuexiong li Tianlong Zhang Dong Wang Qiaoyan Sun libin liu Jinshan li Yuyou Cui Rui Yang Dongsheng Xu Frontier Institute of Science and Technology State Key Laboratory for Mechanical Behavior of MaterialsXi’an Jiaotong UniversityXi’an 710049China Institute of Metal Research Chinese Academy of SciencesShenyang 110016China School of Materials Science and Engineering Central South UniversityChangsha 410083China State Key Laboratory of Solidification Processing Northwestern Polytechnical UniversityXi’an 710072China Thermal Power Research Institute Co.Ltd. Xi’an 710032China

The design of alloys with simultaneous high strength and high ductility is still a difficult ***,we propose a new approach to designing multi-phase alloys with a synergistic combination of strength and ductility by engineering heterogeneous precipitate microstructures through the activation of different transformation *** a two-phase titanium alloy as an example,phase field simulations are carried out firstly to design heat treatment schedules that involve both conventional nucleation and growth and non-conventional pseudospinodal decomposition mechanisms,and the calculated microstructures have been evaluated by crystal plasticity finite element *** to simulations,we then set a two-step heat treatment to produce bimodalα+βmicrostructure in *** mechanical testing shows that the ductility of the alloy is increased by~50%and the strength is increased by~10%as compared to its unimodal *** work may provide a general way to improve the mechanical properties of alloys through multiscale microstructure design.

关键词： Titanium alloys Phase field simulation Crystal plasticity finite element Two-step aging Pseudospinodal decomposition mechanisms Multiscale heterogeneous microstructure

Formation mechanism of α lamellae during β→α transformation in polycrystalline dual-phase Ti alloys

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Journal of Materials Science & Technology 2021年第12期71卷 98-108页

作者： Jia Sun Min Qi Jinhu Zhang xuexiong li Hao Wang Yingjie Ma Dongsheng Xu Jiafeng Lei Rui Yang Institute of Metal Research Chinese Academy of SciencesShenyang 110016China University of Shanghai for Science and Technology Shanghai 200093China University of Chinese Academy of Sciences Beijing 100049China School of Materials Science and Engineering University of Science and Technology of ChinaHefei 230026China

Phase field simulations incorporating contributions from chemical free energy and anisotropic interfacial energy are presented for theβ→αtransformation in Ti-6 Al-4 V alloy to investigate the growth mechanism ofαlamellae of various morphologies from undercooledβ***αcolony close to realistic microstructure was generated by coupling the Thermo-Calc thermodynamic parameters ofαandβphases with the phase field governing *** simulations show thatαlamellar side branches with feathery morphology can form under a certain combination of interfacial energy anisotropy and temperature.αlamellae tend to grow slowly at high heat treatment temperature and become wider and thicker as temperature increase from 800 to 900℃provided that the interfacial energy anisotropy ratio k_(x):k_(y) was set as 0.1:***,higher interfacial energy anisotropy can accelerate the formation ofαlamellae,and the equilibrium shape ofαlamellae changes from rod to plate as the interface energy anisotropy ratio k_(x):k_(y) vary from 0.1:0.4 to 0.1:0.8 under 820℃.Experiments were conducted to study theαlamellar side branches in Ti-6 Al-4 V(Ti-6.01 Al-3.98 V,wt.%)and Ti-4211(Ti-4.02 A1-2.52 V-1.54 Mo-1.03 Fe,wt.%)alloys with lamellar micro *** backscatter diffraction(EBSD)re sults show thatαlamellar side branches and their related lamellae share the same *** predicted temperature range forαlamellar side branches fo rmation under various interfacial energy anisotropy is consistent with experimental results.

关键词： αLamellae Side branches Ti-6Al-4V Interfacial energy anisotropy Phase field model

Phase field simulation of the stress-inducedαmicrostructure in Ti–6Al–4 V alloy and its CPFEM properties evaluation

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Journal of Materials Science & Technology 2021年第31期90卷 168-182页

作者： Jinhu Zhang xuexiong li Dongsheng Xu Chunyu Teng Hao Wang liang Yang Hongtao Ju Haisheng Xu Zhichao Meng Yingjie Ma Yunzhi Wang Rui Yang Institute of Metal Research Chinese Academy of SciencesShenyang 110016China Shi-changxu Innovation Center for Advanced Materials Institute of Metal ResearchChinese Academy of SciencesShenyang 110016China China Aero-Polytechnology Establishment Beijing 100028China School of Materials Science and Engineering University of Science and Technology of ChinaShenyang 110016China Department of Materials Science and Engineering The Ohio State University2041 Collesnited States

Variant selection under specific applied stresses during precipitation of a plates from prior-βmatrix in Ti-6 Al-4 V was investigated by 3 D phase field *** model incorporates the Burgers transformation path fromβto a phase,with consideration of interfacial energy anisotropy,externally applied stresses and elastic interactions among a variants andβ*** Gibbs free energy and atomic mobility data are taken from available thermodynamic and kinetic *** was found that external stresses have a profound influence on variant selection,and the selection has a sensitive dependence,as evidenced by both interaction energy calculations and phase field *** with normal stresses,shear stresses applied in certain directions were found more effective in accelerating the transformation,with a stronger preference to fewer *** volume fractions of various a variants and the final microstructure were determined by both the external stress and the elastic interaction among different *** a clusters formed by variants with Type2 misorientation([11-20]/60°)relation were found more favored than those with Type4([-1055-3]/63.26°)under certain applied tensile stress such as alongβ.The mechanical properties of different microstructures from our phase field simulation under different conditions were calculated for different loading conditions,utilizing crystal plastic finite element *** mechanical behavior of the various microstructures from phase field simulation can be evaluated well before the alloys are fabricated,and therefore it is possible to select microstructure for optimizing the mechanical properties of the alloy through thermomechanical processing based on the two types of simulations.

关键词： Titanium alloy Phase transformation Microtexture Mechanical evaluation Phase field Crystal plasticity finite element

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双相钛合金高温变形协调性的CPFEM研究

金属学报 2019年第7期55卷 928-938页

作者：李学雄徐东生杨锐中国科学院金属研究所沈阳110016 中国科学院大学北京100049

基于率相关滑移为主的晶体塑性本构模型,结合Voronoi方法创建双相多晶体集合,研究不同组织特征的Ti-6Al-4 V合金的高温变形行为,重点关注双相组织中应力、应变空间分布特征及其演化,应力、应变相间分配,并提出一种变形协调性定量评估方... 详细信息

基于率相关滑移为主的晶体塑性本构模型,结合Voronoi方法创建双相多晶体集合,研究不同组织特征的Ti-6Al-4 V合金的高温变形行为,重点关注双相组织中应力、应变空间分布特征及其演化,应力、应变相间分配,并提出一种变形协调性定量评估方法。结果表明,多晶变形过程中,晶界及其附近是变形的优先响应区域;β晶粒与a晶粒之间存在包围结构特征可加剧局域应变的差异分配;晶粒长短轴比越大,周围异相界面越多,则其局域变形协调性越低。α和β相应力频率统计呈双峰形态,α相中平均应变较高,而β相中应力较高。随α相体积分数增加,拉伸屈服强度和应力协调系数降低,而应变协调系数先降低后升高。随α基面织构体积分数增加,拉伸屈服强度和加工硬化率升高,且应力协调系数升高,而应变协调系数先降低后升高。

关键词：双相钛合金 Voronoi 晶体塑性有限元法应力应变分配变形协调性

钛合金双态组织高温拉伸行为的晶体塑性有限元研究

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材料研究学报 2019年第4期33卷 241-253页

作者：李学雄徐东生杨锐中国科学院金属研究所沈阳110016 中国科学院大学北京100049

创建一个包含多变体结构特征的双态组织几何模型,提出一种变形协调性的评估方法,采用以率相关滑移为主的晶体塑性有限元本构关系,研究了具有不同组织特征的Ti-6Al-4V合金双态组织的高温拉伸行为。结果表明:在多晶变形过程中,α_p相承载... 详细信息

创建一个包含多变体结构特征的双态组织几何模型,提出一种变形协调性的评估方法,采用以率相关滑移为主的晶体塑性有限元本构关系,研究了具有不同组织特征的Ti-6Al-4V合金双态组织的高温拉伸行为。结果表明:在多晶变形过程中,α_p相承载了更多的应变;在变形后的样品中,出现了大致对称分布于拉伸方向两侧的高应变交叉条带;存在于α_p与β_T之间的包围结构特征,可加剧局域应变分配的差异;随着α_p相体积分数的升高应变量降低,整体应变协调性先较快降低而后平稳;随着α_s片层厚度的增加高应变条带特征弱化,整体应变协调系数升高;含双变体α_s片层团簇结构的β_T组织,其应变协调性低于含单变体和三变体的组织。

关键词：材料科学基础学科变形协调性晶体塑性有限元钛合金双态组织应力应变分配

Distribution of α-D-mannose residues on zona pellucida and their role(s) in fertilization in pigs

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Science China(life Sciences) 2007年第2期50卷 170-177页

作者： SONG xuexiong1, li FangZheng1, CAO GuoQiang1, ZHANG JinYu1 & HAN YiBing2 1 Faculty of Animal Science and Technology, Laiyang Agricultural College, Qingdao 266109, China 2 Department of Obstetrics & Gynecology, Chinese University of Hong Kong, Hong Kong Faculty of Animal Science and Technology Laiyang Agricultural College Qingdao China Department of Obstetrics & Gynecology Chinese University of Hong Kong Hong Kong China

The present study aims to identify the distribution of α-D-mannose residues on zona pellucida (ZP) and their role(s) in fertilization in pigs. In experiment 1, in vitro matured pig oocytes were freed from cu- mulus cells and treated with fluorescein isothiocyanate-labelled Lens culinaris (FITC-LCA), a D-mannose specific binding lectin. After 30 min of treatment, LCA bound evenly throughout the ZP with strong fluorescence. In experiment 2, when LCA-treated oocytes were used for in vitro fertilization, the number of sperm bound to ZP was significantly decreased, and sperm penetration was almost com- pletely blocked. In experiment 3, polysaccharide mannan was added to the in vitro fertilization medium as a competitive inhibitor. Both the number of sperm bound to ZP and the rate of fertilized oocytes were significantly reduced in the mannan-treated group compared with the control group. In experiment 4, spermatozoa were incubated with mannan in vitro. The number of acrosome-reacted spermatozoa was evidently increased in a time-dependent manner during the incubation. These results suggest that α-D-mannose residues presenting on pig ZP might be an important component of sperm receptor and might induce sperm acrosome reaction and thus facilitate the sperm penetration into the ZP.

关键词： α-D-mannose residues zona pellucida fertilization Lens culinaris pig

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广州市南湖近五年水质分析评价与保护探讨

广东化工 2019年第13期46卷 129-130,103页

作者：李学雄广州市白云区环境监测站

南湖水域是首批国家级的旅游度假区,是白海面涌上游、白海面中央湿地公园的主要供水源头。文章根据南湖2014-2018年水质监测资料,按照《地表水环境质量标准》(GB3838-2002)的单因子评价法,并结合内梅罗污染指数综合评价法,来对南湖水质... 详细信息

南湖水域是首批国家级的旅游度假区,是白海面涌上游、白海面中央湿地公园的主要供水源头。文章根据南湖2014-2018年水质监测资料,按照《地表水环境质量标准》(GB3838-2002)的单因子评价法,并结合内梅罗污染指数综合评价法,来对南湖水质进行分析与评价。通过水质的评价分析为南湖水质治理提供科学依据、数据支撑与方法指引。结果表明:南湖水体主要污染物是总氮、总磷,水体处于轻污染或污染状态,水质类别为劣Ⅴ类。

关键词：南湖中央湿地公园内梅罗污染指数水质评价治理保护

Ti-6Al-4V合金β→α相变中晶界α相形成机制的相场模拟

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金属学报 2020年第8期56卷 1113-1122页

作者：孙佳李学雄张金虎王刚杨梅王皞徐东生中国科学院金属研究所沈阳110016 中国科学院大学北京100049 华南理工大学材料科学与工程学院广州510006 江苏理工学院材料工程学院常州213001 中国科学技术大学材料科学与工程学院沈阳110016

使用相场模型研究了Ti-6Al-4V合金在β→α相变过程中晶界α相(αGB)的形核及晶界润湿生长过程。通过耦合Thermo-Calc热力学数据与相场模型模拟出的组织与实际形貌一致。结果表明,特殊构造的噪声项使β/β晶界处失稳,并促进α相在晶界... 详细信息

使用相场模型研究了Ti-6Al-4V合金在β→α相变过程中晶界α相(αGB)的形核及晶界润湿生长过程。通过耦合Thermo-Calc热力学数据与相场模型模拟出的组织与实际形貌一致。结果表明,特殊构造的噪声项使β/β晶界处失稳,并促进α相在晶界上的形核。相变初期析出的α相颗粒较多的情况下生成的αGB形貌为连续的平滑状;反之,较少的α初始核会导致不连续αGB的生成,模拟结果揭示了实验中不同形貌αGB的形成机制。晶界润湿由不完全润湿到完全润湿可以是一个连续过程而不需其它反应即可实现。随噪声时间从50 s延长到80 s,αGB晶界润湿速率越来越快,且α相的体积分数逐渐增大;随噪声强度由0.05增大到0.11,反应速率也逐渐加快,而α相体积分数可能先增大后减小。噪声时间与强度对αGB形貌影响的规律与实验观察到的不同条件下的αGB形貌一致,可为晶界α相及合金的疲劳性能的控制提供信息。

关键词： Ti-6Al-4V 相场噪声项 αGB 晶界润湿相变

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TC6钛合金的高温拉伸蠕变行为研究

稀有金属材料与工程 2013年第9期42卷 1901-1904页

作者：李学雄夏长清戚延龄王志辉牛国帅孙玮中南大学湖南长沙410083 湖南三一重工总部湖南长沙410083

通过高温拉伸蠕变实验,获得了TC6合金的蠕变应变-时间曲线,并计算了其不同应力与不同温度下的稳态蠕变速率、应力指数及在350～450℃范围内的蠕变激活能,借助OM、TEM等手段对合金蠕变前后的显微组织进行了观察和分析,并在此基础上研究... 详细信息

通过高温拉伸蠕变实验,获得了TC6合金的蠕变应变-时间曲线,并计算了其不同应力与不同温度下的稳态蠕变速率、应力指数及在350～450℃范围内的蠕变激活能,借助OM、TEM等手段对合金蠕变前后的显微组织进行了观察和分析,并在此基础上研究了其蠕变变形机制。结果表明:TC6合金的稳态蠕变速率随温度或恒应力的增加而增大,该合金在此温度范围内的蠕变受位错和扩散双重机制的控制,晶界滑动对蠕变也有一定的作用。

关键词： TC6 蠕变显微组织蠕变机制