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Phase field modeling of ferroelastic variant switching in yttria-stabilized t'zirconia with strain gradient elasticity and interface tension

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Science China(Technological Sciences) 2024年第5期67卷 1443-1457页

作者： zhou QianQian WEI YueGuang zhou yichun YANG Li College of Engineering BIC-ESATPeking UniversityBeijing100871China School of Advanced Materials and Nanotechnology Xidian UniversityXi’an710126China Frontier Research Center of Thin Films and Coatings for Device Applications Academy of Advanced Interdisciplinary ResearchXidian UniversityXi’an710126China

The 6–8 wt%yttria-stabilized zirconia with a tetragonal structure(t’-YSZ)is extensively employed in thermal barrier *** exceptional fracture toughness of t’-YSZ can be attributed to its distinctive ferroelastic toughening *** and interface tension play a critical role in ferroelastic variant switching at the micro-and *** paper presents an original thermodynamically consistent phase field(PF)theory for analyzing ferroelastic variant switching at the micro-and nano-scale of t’-*** theory incorporates strain gradient elasticity using higher-order elastic energy and interface tension tensor via geometric nonlinearity to represent biaxial tension resulting from interface ***,a mixed-type formulation is employed to implement the higher-order theory through the finite element *** an interface in equilibrium,the effects of strain gradient elasticity result in a more uniform distribution of stresses,whereas the presence of interface tension tensor significantly amplifies the stress magnitude at the *** introduction of an interface tension tensor increases the maximum value of stress at the interface by a factor of 4 to *** nucleation and evolution of variants at a pre-existing crack tip in a mono-phase t’-YSZ have also been *** strain gradient elasticity is capable of capturing the size effect of ferroelastic variant switching associated with microstructures in ***,when the grain size approaches that of the specimen,the critical load required for variant switching at the crack tip increases,resulting in greater dissipation of elastic energy during ferroelastic variant ***,the interface tension accelerates the evolution of *** presented framework exhibits significant potential in modeling ferroelastic variant switching at the micro-and nano-scale.

关键词： thermodynamics strain gradient elasticity interface tension phase field method ferroelastic variant switching

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Hf_(x)Ta_(1-x)C体系力学性能及熔化曲线的第一性原理研究

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无机材料学报 2024年第7期39卷 761-768,I0001,I0002页

作者：吴玉豪彭仁赐程春玉杨丽周益春西安电子科技大学先进材料与纳米科技学院陕西省空天高电子轨道材料与防护技术重点实验室西安710126

Hf_(x)Ta_(1-x)C具有高熔化温度、高硬度、高强度,以及导电、导热性好等优异性能,是2000℃以上热防护领域极有潜力的候选材料,但其力学性质与熔化温度随组分变化规律尚不清晰。本研究基于特殊准随机结构(SQS)方法和第一性原理计算,从共... 详细信息

Hf_(x)Ta_(1-x)C具有高熔化温度、高硬度、高强度,以及导电、导热性好等优异性能,是2000℃以上热防护领域极有潜力的候选材料,但其力学性质与熔化温度随组分变化规律尚不清晰。本研究基于特殊准随机结构(SQS)方法和第一性原理计算,从共价键强度、价电子浓度(VEC)的微观角度系统地探讨了Hf_(x)Ta_(1-x)C系固溶体力学性质随组分的变化机理。力学性质计算结果表明:5种组分(HfC、Hf0.75Ta0.25C、Hf0.5Ta0.5C、Hf0.25Ta0.75C与TaC)中,Hf0.25Ta0.75C固溶体具有最高的弹性模量和剪切模量,这主要归因于:(1)该组分具有最高的共价键强度;(2)来自C的p轨道和来自Hf或Ta的d轨道之间的特殊键合在VEC=8.75(Hf0.25Ta0.75C)附近被完全填充,它们强烈抑制形状变化。研究还使用基于从头算分子动力学(AIMD)的分子动力学Z方法计算了Hf_(x)Ta_(1-x)C系固溶体的熔化曲线。结果显示Hf_(x)Ta_(1-x)C系固溶体熔化温度反常增加的现象的确存在,且在Hf0.5Ta0.5C处熔化温度最高(4270 K),这主要归因于构型熵与共价键强度的协同作用。本研究结果为高熔化温度及高力学性能Hf_(x)Ta_(1-x)C系固溶体组分的实验选择及其耐高温涂层应用等提供了理论指导,也为其他过渡金属碳化物研究提供了参考。

关键词： Hf_(x)Ta_(1-x)C 第一性原理力学性质熔化温度

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发酵茅台白酒糟及可溶物对蛋鸡产蛋性能、蛋品质、粪便微生物的影响

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中国饲料 2024年第9期 125-130页

作者：夏军邹益春胡芳刘建忠张飞路德环境科技股份有限公司湖北武汉430070 路德生物环保技术(亳州)有限公司安徽亳州236800

为研究不同水平发酵茅台白酒糟及可溶物(FMDGS)对蛋鸡产蛋性能、蛋品质、粪便微生物的影响,试验选取健康、体况基本一致的30周龄罗曼粉蛋鸡1200只,随机分为对照组和3个试验组,对照组饲喂基础日粮,试验Ⅰ、Ⅱ、Ⅲ组分别在基础日粮中添加1... 详细信息

为研究不同水平发酵茅台白酒糟及可溶物(FMDGS)对蛋鸡产蛋性能、蛋品质、粪便微生物的影响,试验选取健康、体况基本一致的30周龄罗曼粉蛋鸡1200只,随机分为对照组和3个试验组,对照组饲喂基础日粮,试验Ⅰ、Ⅱ、Ⅲ组分别在基础日粮中添加1.5%发酵茅台白酒糟(FMDG),1.5%FMDGS,1%FMDGS,每组5个重复,每个重复60只鸡。预试期10 d,正试期40 d。结果表明:与对照组相比,试验Ⅱ、Ⅲ组在试验21~40 d产蛋率分别显著提高0.78个百分点和1.43个百分点(P<0.05),1~40 d试验组产蛋率有提高趋势(P=0.08);与对照组相比,试验Ⅱ组蛋形指数显著提高(P<0.05);与对照组相比,试验各组蛋鸡粪便中芽孢杆菌数量均显著增加(P<0.05)。添加1.5%FMDG,1.5%FMDGS,1%FMDGS均能不同程度改善蛋鸡产蛋性能,提高蛋品质,促进有益菌的增殖。综合来看,日粮添加1.5%FMDGS,蛋鸡产蛋性能、蛋品质、粪便微生物指标表现最好,效果最佳。

关键词：发酵茅台白酒糟及可溶物蛋鸡产蛋性能蛋品质粪便微生物

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A chemo-thermo-mechanically constitutive theory of high-temperature interfacial oxidation in alloys under deformation

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Science China(Technological Sciences) 2023年第4期66卷 1018-1037页

作者： zhou QianQian YANG Li NIE Min zhou yichun WEI YueGuang College of Engineering BIC-ESATPeking UniversityXi'an 710126China School of Advanced Materials and Nanotechnology Xidian UniversityBeijing 100871China Frontier Research Center of Thin Films and Coatings for Device Applications Academy of Advanced Interdisciplinary ResearchXidian UniversityXi'an 710126China AECC Hunan Aviation Powerplant Research Institute Zhuzhou 412002China

Failure due to interfacial oxidation is one of the most important factors in the failure of alloy systems at high *** analyze high-temperature interfacial oxidation in alloys under deformation,we develop a thermodynamically consistent continuum theory of alloy interfacial oxidation process considering diffusion,oxidation,expansion,viscoplasticity,and deformation *** equations of force,mass,and energy are presented at first,while the coupled constitutive laws and evolution equations are constructed according to energy dissipation *** coupled kinetics reveals a new mechanism whereby deformation affects the oxidation reaction by changing the alloy’s critical oxygen *** tensile loads decrease the critical oxygen concentration and promote oxidation of the ***,external compressive loads increase the critical oxygen concentration and suppress the oxidation of the ***,this theory is applied to thermal barrier coatings(TBCs),exhibiting a good consistency with the high-temperature oxidation experiment of TBCs under external *** model successfully explains that the experimental phenomenon of external tensile load accelerates the growth of Al_(2)O_(3)-TGO(thermally grown oxides).Besides,external compressive loads slow down the growth of Al_(2)O_(3)-TGO at the interface and lead to internal oxidation of the bond *** presented framework has shown great potential for modeling high-temperature interfacial oxidation processes in alloy systems under deformation.

关键词： thermodynamics oxidation oxygen diffusion chemo-thermo-mechanically coupling alloy

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三级公立医院绩效考核背景下住院病案首页的监管成效

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中国病案 2024年第3期25卷 4-7页

作者：周一春唐子豪淮安市第二人民医院江苏省淮安市223001

目的分析三级公立医院绩效考核指标及内涵,提高住院病案首页填写质量,促进医院精细化管理。方法2019年底基于三级公立医院绩效考核指标体系对全员进行住院病案首页培训,随机抽取某院2019年1月1日-2019年12月31日(培训前)和2020年1月1日-... 详细信息

目的分析三级公立医院绩效考核指标及内涵,提高住院病案首页填写质量,促进医院精细化管理。方法2019年底基于三级公立医院绩效考核指标体系对全员进行住院病案首页培训,随机抽取某院2019年1月1日-2019年12月31日(培训前)和2020年1月1日-2020年12月31日(培训后)各5000份的住院病案首页进行质量检查,并采用SPSS 26.0进行统计分析。结果住院病案首页相对于培训前,培训后2020年的住院病案首页整体质量显著优于培训前2019年。A、B、C、D四类项目的错误已实现跳崖式减少,整体病案首页优秀率上涨了25.44%,基本信息和诊疗信息缺陷率分别由54.54%和36.35%下降为49.55%和30.82%。此外基本信息中的D类项目中地址以及诊疗信息中的A类项目中疾病诊断和手术操作的缺陷率也分别由59.26%和36.35%降至58.91%和30.82%。结论建立以三级公立医院绩效考核住院病案首页指标为导向的住院病案首页质量监控体系,通过对全院医务人员的培训、信息系统的优化、奖惩机制的建立以及病案的督查管理,有助于持续提高住院病案首页质量,为三级公立医院绩效考核奠定了坚实的基础。

关键词：住院病案首页质量控制持续改进

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Transformation toughening in zirconium tantalum ceramics

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Science China(Technological Sciences) 2022年第8期65卷 1772-1779页

作者： LI Cong TAN Dan LUO Cheng LUO JunHui CAO Ke YANG Li zhou yichun School of Advanced Materials and Nanotechnology Xidian UniversityXi’an 710126China Frontier Research Center of Thin Films and Coatings for Device Applications Academy of Advanced Interdisciplinary ResearchXidian UniversityXi’an 710126China School of Materials Science and Engineering Xiangtan UniversityXiangtan 411105China

Toughness enhancement of zirconium tantalum ceramics is conducive to the new generation of thermal barrier coatings(TBCs).The phase transformation toughening mechanism of zirconium tantalum ceramics has been explored through the Vickers indentation of YTaO_(4) ceramic block,the phase transformation region is found near the indentation and the microcrack *** increased energy of stable phaseΔE_(M.M′)>0,and the volume expandedΔV≈1.9%,so,the phase transformation is a process of energy *** additional stressσa restraining the crack propagation was generated in the shielding area at the crack *** addition,combined with the toughening of ferroelastic domains switch,the traditional microcrack toughening,and crack propagation toughening,we summarized the toughening mechanism of YTaO_(4) ceramics with the increasing external load,which is followed by ferroelastic toughening,phase transformation,microcrack,and crack *** the perspective of toughening,we found that Z^(4+) doping in YTaO_(4) ceramics could broaden the phase transformation range in phase transformation toughening,significantly improve the toughness and reduce the generation of cracks in microcrack toughening and crack propagation ***,toughening mechanism of zirconium tantalum ceramics has important guiding significance for the service of TBCs.

关键词： transformation toughening crack tip YTaO_(4)ceramics toughening mode

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Domain Wall Evolution in Hf_(0.5)Zr_(0.5)O_(2)Ferroelectrics under Field-Cycling Behavior

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Research 2023年第4期6卷 415-423页

作者： Sirui Zhang Qinghua Zhang Fanqi Meng Ting Lin Binjian Zeng Lin Gu Min Liao yichun zhou School of Advanced Materials and Nanotechnology Xidian UniversityXi’an 710071China Beijing National Laboratory for Condensed Matter Physics Institute of PhysicsChinese Academy of SciencesBeijing 100190China School of Materials Science and Engineering Xiangtan UniversityXiangtan 411105China School of Materials Science and Engineering Tsinghua UniversityBeijing 100084China

HfO_(2)-based ferroelectrics have evoked considerable interest owing to the complementary metal-oxide semiconductor compatibility and robust ferroelectricity down to a few unit ***,the unique wake-up effect of HfO_(2)-based ferroelectric films severely restricts the improvement of their *** particular,the domain structure is an important characteristic of ferroelectric materials,which still has not been well understood in HfO_(2)-based *** this work,a Hf_(0.5)Zr_(0.5)O_(2) ferroelectric thin film is grown on a typical Si substrate buffered with TiN *** 90°domains of the Pca21 ferroelectric phase with head-to-tail and tail-to-tail structures can be observed by Cs-corrected scanning transmission electron microscope under their pristine *** waking up,the 180°domain is displayed in the ferroelectric *** remarkable differences in domain walls for 90°and 180°domains are characterized by qualitatively mapping the polarization distributions at the atomic *** domain wall changes from the[101]of the Hf_(0.5)Zr_(0.5)O_(2) film to the[001]of the Hf_(0.5)Zr_(0.5)O_(2) *** result provides fundamental information for understanding the domain structure of HfO_(2)-based ferroelectrics.

关键词： ferroelectric film walls

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Ferroelastic domain identification and toughening mechanism for yttrium tantalate–zirconium oxide

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Journal of Materials Science & Technology 2022年第32期127卷 78-88页

作者： Cheng Luo Cong Li Ke Cao Junbao Li Junhui Luo Qinghua Zhang QianQian zhou Fan Zhang Lin Gu Li Yang yichun zhou School of Advanced Materials and Nanotechnology Xidian UniversityXi’an 710126China Frontier Research Center of Thin Films and Coatings for Device Applications Academy of Advanced Interdisciplinary ResearchXidian UniversityXi’an 710126China School of Materials Science and Engineering Xiangtan UniversityXiangtan 411105China Beijing National Laboratory for Condensed Matter Physics Institute of PhysicsChinese Academy of SciencesBeijing 100190China College of Engineering BIC-ESATPeking UniversityBeijing 100871China

Yttrium tantalate(YTaO_(4))is the next generation of higher service temperature thermal barrier coatings(TBCs)materials due to its smaller volume effect in phase change,lower thermal conductivity and unique ferroelastic domain ***,the low fracture toughness limits its *** first characterized the diffraction patterns of variants,and two variants(M_(1)and M_(2))observed in transmission electron microscopy(TEM)results were determined from four possible variants by mechanical *** role of Zr^(4+)doping in ferroelastic toughening was explained in *** the increase of Zr^(4+)doping concentration,the monoclinic angle β and the domain rotation angleαdecrease,*** spontaneous strain component and the principal strain in the main space also have a similar decreasing *** decrease of the ferroelastic domain inversion energy barrier is beneficial to the improvement of fracture *** the results of Vickers indentation,we found that Zr^(4+)could be enriched at the domain boundary to inhibit the generation of *** appropriate amount of Zr^(4+)is conducive to the improvement of fracture toughness,and the excessive Zr^(4+)will reduce the fracture toughness due to the generation of by-product t-ZrO_(2).So,the optimal composition is Y_(0.44)Ta_(0.44)Zr_(0.12)O_(2) and the best fracture toughness(2.9–3.8MPa m^(1/2))is equivalent to the commercial *** result will promote the application of a new generation of TBCs.

关键词： Ferroelastic domain Variants Domain switch TBCs Fracture toughness

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HfO_(2)-based ferroelectric thin film and memory device applications in the post-Moore era:A review

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Fundamental Research 2023年第3期3卷 332-345页

作者： Jiajia Liao Siwei Dai Ren-Ci Peng Jiangheng Yang Binjian Zeng Min Liao yichun zhou a School of Advanced Materials and Nanotechnology Xidian UniversityXi’an 710126China Frontier Research Center of Thin Films and Coatings for Device Applications Academy of Advanced Interdisciplinary ResearchXidian UniversityXi’an 710126China Key Laboratory of Low Dimensional Materials and Application Technology of Ministry of Education School of Materials Science and EngineeringXiangtan UniversityXiangtan 411105China

The rapid development of 5G,big data,and Internet of Things(IoT)technologies is urgently required for novel non-volatile memory devices with low power consumption,fast read/write speed,and high reliability,which are crucial for high-performance *** memory has undergone extensive investigation as a viable alternative for commercial applications since the post-Moore ***,conventional perovskite-structure ferroelectrics(e.g.,PbZr_(x)Ti_(1-x)O_(3))encounter severe limitations for high-density integration owing to the size effect of ferroelectricity and incompatibility with complementary metal-oxide-semiconductor *** 2011,the ferroelectric field has been primarily focused on HfO_(2)-based ferroelectric thin films owing to their exceptional *** reviews discussing the control of ferroelectricity and device applications *** is believed that a comprehensive understanding of mechanisms based on industrial requirements and concerns is necessary,such as the wake-up effect and fatigue *** mechanisms reflect the atomic structures of the materials as well as the device ***,a review focusing on phase stability and domain structure is *** addition,the recent progress in related ferroelectric memory devices and their challenges is briefly discussed.

关键词： Hfo_(2)ferroelectrics Phase stability Domain structure Wake-up Fatigue Ferroelectric field-effect transistor

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An Improved Process for Bifacial n-PERT Solar Cells Fabricated with Phosphorus Activation and Boron Diffusion in One-step High Temperature

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Journal of Wuhan University of Technology(Materials Science) 2022年第6期37卷 1056-1060页

作者： LIU Renjie 尹路周益春 Key Laboratory of Low Dimensional Materials and Application Technology of Ministry of Education School of Materials Science and EngineeringXiangtan UniversityXiangtan 411105China

The bifacial n-PERT(Passivated Emitter Rear Totally diffused)solar cells were fabricated using a simplified process in which the activation of ion-implanted phosphorus and boron diffusion were performed simultaneously in a high-temperature *** further efficiency improvement,the rear side doping level was regulated by applying two different implantation doses and the chemical etching step of boron rich layer(BRL)was added,and their effects on cell performance were *** solar cells average efficiency reaches 20.35%with a bifaciality factor of 90%by optimizing rear side doping level,which can be explained by the decrease of Auger *** it is further enhanced to 20.74%by removing the front side BRL due to the improvement of surface passivation and bulk *** improved fabrication process possesses the advantages of low complexity and cost and high cell efficiency and bifaciality factor which could provide a promising way to the commercial production of bifacial n-PERT solar cells.

关键词： n-PERT solar cells ion implantation diffusion bifacial structure

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