检索结果-南通市图书馆

Sparse identification-assisted exploration of the atomic-scale deformation mechanism in multiphase CoCrFeNi high-entropy alloys

在线全文

学校读者我要写书评

暂无评论

Science China(Technological Sciences) 2024年第4期67卷 1124-1132页

作者： XIAO Lu GUO XiaoXiang SUN YuTong WANG Gang long weimin LIAW Peter K. REN JingLi School of Mathematics and Statistics Zhengzhou UniversityZhengzhou 450001China Academy of Mathematics and Systems Science Chinese Academy of SciencesBeijing 100190China Institute of Materials Shanghai UniversityShanghai 200444China SKL of Advanced Brazing Metals&Technology Zhengzhou Research Institute of Mechanical EngineeringZhengzhou 450001China Department of Materials Science and Engineering The University of TennesseeKnoxvilleTN 37996USA

This study investigated the atomic-scale deformation mechanism of multiphase CoCrFeNi high-entropy alloys(HEAs)at liquid helium,liquid nitrogen,and room temperatures.A million-atom multiphase HEA was prepared using molecular dynamics simulation involving melt and quench *** HEA exhibited high-density dislocations and some twins,consistent with experimental *** analysis revealed an inconsistent evolution of the microstructure under tensile *** particular,the elastic and initial plastic stages exhibited an increase in the disordered structure at the expense of the face-centered cubic and hexagonal close-packed structures,followed by a subsequent transformation involving multiple structural ***,through sparse identification,a model depicting microstructural evolution during tension was extracted for the CoCrFeNi HEA at three typical temperatures and three tensile *** model highlighted the importance of the body-centered cubic structure in the evolutionary process.

关键词： high-entropy alloy data-driven method microstructure evolution multiphase structure molecular dynamics simulation

YG8/GH4169异种材料钎焊接头残余应力的数值模拟

在线全文

学校读者我要写书评

暂无评论

焊接学报 2024年第3期45卷 68-74,I0006,I0007页

作者：乔瑞林龙伟民秦建廖志谦樊喜刚魏永强郑州机械研究所有限公司新型钎焊材料与技术国家重点实验室郑州450001 北京科技大学北京100083 洛阳船舶材料研究所洛阳471039 北京星航机电装备有限公司北京100074 郑州航空工业管理学院郑州450046

钻探采样技术是实现月球土壤样本采集的首选方法,针对钻采工具中异种材料钎焊接头残余应力大、连接质量差等问题,以ANSYS有限元软件为平台,采用数值模拟方法,分析了YG8/GH4169钎焊接头残余应力的分布情况,以及添加Cu,Mo中间层时对接头... 详细信息

钻探采样技术是实现月球土壤样本采集的首选方法,针对钻采工具中异种材料钎焊接头残余应力大、连接质量差等问题,以ANSYS有限元软件为平台,采用数值模拟方法,分析了YG8/GH4169钎焊接头残余应力的分布情况,以及添加Cu,Mo中间层时对接头残余应力的影响规律.结果表明,在硬质合金/高温合金钎焊接头中存在极大的残余应力,硬质合金靠近焊缝的顶点附近为应力集中的危险区域,最大轴向残余应力约为1304 MPa;添加Cu,Mo中间层均能有效缓解接头残余应力,当中间层厚度小于0.6 mm时,Cu对接头残余应力的缓解效果更好,中间层厚度大于0.6 mm时,Mo的缓解效果更佳;Cu,Mo作为中间层时,缓解接头残余应力的最佳厚度均为1.0 mm左右,异种材料钎焊接头残余应力的试验结果与数值模拟结果基本吻合.

关键词：数值模拟残余应力硬质合金高温合金钎焊

在线全文

学校读者我要写书评

暂无评论

航空航天领域常用高温钎料研究现状

精密成形工程 2024年第7期16卷 191-204页

作者：祖家泽马佳秦建龙伟民郑州机械研究所有限公司新型钎焊材料与技术国家重点实验室郑州450001

近年来随着航空航天工业的发展,各类飞行器核心功能部件面临着使役环境愈发极端化的问题。超高速、高温等服役环境对各类零部件的整体性能提出了更高的要求,因此针对航空航天领域用高温钎料的研究尤为重要。在航空航天领域常用的高温钎... 详细信息

近年来随着航空航天工业的发展,各类飞行器核心功能部件面临着使役环境愈发极端化的问题。超高速、高温等服役环境对各类零部件的整体性能提出了更高的要求,因此针对航空航天领域用高温钎料的研究尤为重要。在航空航天领域常用的高温钎料包括镍基钎料、钴基钎料、钛基钎料、锰基钎料、贵金属钎料和高熵钎料等,通常应用于不锈钢、高温合金、钛合金以及新型陶瓷材料等的钎焊连接。主要针对在航空航天领域中常用的几种高温钎料,对钎料的元素组成和特性进行总结,对钎料的成形特点和工艺进行介绍,对研究和应用现状进行分析,并对航空航天领域的钎料与钎焊技术提出建议与展望,以期为提升钎焊技术在航空航天领域的应用价值提供参考和指导。

关键词：高温钎料镍基钎料钴基钎料钛基钎料锰基钎料贵金属钎料高熵钎料航空航天

Effect of Thermal Cyclic Loading on Stress-Strain Response and Fatigue Life of 3D Chip Stacking Structure

同方期刊数据库博看期刊评论

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of Mechanical Engineering 2021年第6期34卷 353-361页

作者： Liang Zhang weimin long Sujuan Zhong Zhengzhou Research Institute of Mechanical Engineering Co. LTDZhengzhou450001China School of Mechatronic Engineering Jiangsu Normal UniversityXuzhou221116China

The thermo-mechanical reliability of IMCs(Ni_(3)Sn_(4),Cu_(3)Sn,Cu_(6)Sn_(5))solder joints and Sn-3.9Ag-0.6Cu solder joints was investigated systematically in 3D chip stacking structure subjected to an accelerated thermal cyclic loading based on finite element simulation and Taguchi *** of different control factors,including high temperature,low temperature,dwell time of thermal cyclic loading,and different IMCs on the stress-strain response and fatigue life of solder joints were calculated *** results indicate that maximum stress-strain can be found in the second solder joint on the diagonal of IMC solder joints array;for Sn-3.9Ag-0.6Cu solder joints array,the corner solder joints show the obvious maximum stress-strain,these areas are the crack propagated *** stress-strain and fatigue life of solder joints is more sensitive to dwell temperature,especially to high temperature;increasing the high temperature,dwell time,or decreasing the low temperature,can reduce the stress-strain and enlarge the fatigue life of solder ***,the optimal design in the 3D-IC structure has the combination of the Cu_(6)Sn_(5)/Cu_(3)Sn,373 K high temperature,233 K low temperature,and 10 min dwell *** fatigue lives of Sn-3.9Ag-0.6Cu under 218-398 K loading in the 3D assembly based on the creep strain are 347.4 cycles,which is in good agreement with experimental results(380 cycles).

关键词： 3D-IC Taguchi method Control factors Fatigue life

置氢TA10合金焊接接头组织和高温压缩性能

在线全文

学校读者我要写书评

暂无评论

焊接学报 2024年第8期45卷 79-84,94页

作者：刘全明肖俊峰高斯峰唐文书高松龙伟民西安热工研究院有限公司西安710032 郑州机械研究所有限公司郑州450001

航改燃气轮机焊接修复的钛合金叶片服役于含氢环境中常发生氢脆损伤.试验重点研究了不同置氢量的钛合金氩弧焊接头的微观组织、维氏硬度及氢作用机理、高温压缩性能.结果表明,置氢0.12%(质量分数)焊接接头组织中析出大层片δ氢化物,其... 详细信息

航改燃气轮机焊接修复的钛合金叶片服役于含氢环境中常发生氢脆损伤.试验重点研究了不同置氢量的钛合金氩弧焊接头的微观组织、维氏硬度及氢作用机理、高温压缩性能.结果表明,置氢0.12%(质量分数)焊接接头组织中析出大层片δ氢化物,其尺寸随H元素含量增加而增大,母材、热影响区及焊缝微观组织发生明显改变;置氢0.21%的硬度明显高于其它置氢量,高氢提升焊接接头硬度;低氢时氢固溶强化使α晶粒硬度略提升,高氢时氢化物析出伴随晶格体积膨胀使金属局部塑性变形产生大量位错,位错运动需绕或切过氢化物,导致α晶粒硬度明显提升.压下量对高温压缩流变应力影响有限,再结晶软化作用主要受变形温度控制,随压下量增大,焊缝组织中层片α晶粒连同氢化物沿垂直压下方向被拉长或与压下方向呈一定角度被弯折,氢化物沿层片α晶界生长,热压缩过程中组织再结晶现象不明显.

关键词：钛合金焊接接头置氢微观组织维氏硬度高温压缩性能

超声冲击对增材制造组织改善及强化机理影响的研究进展

在线全文

学校读者我要写书评

暂无评论

金属学报 2024年第3期60卷 273-286页

作者：孙徕博黄陆军黄瑞生徐锴武鹏博龙伟民姜风春方乃文中国机械总院集团哈尔滨焊接研究所有限公司哈尔滨150028 哈尔滨工业大学材料科学与工程学院哈尔滨150001 郑州机械研究所有限公司新型钎焊材料与技术国家重点实验室郑州450001 哈尔滨工程大学烟台研究院烟台264000

增材制造作为一种快速发展的先进技术已在制造业领域得到广泛应用,但在金属制件增材制造过程中存在的晶粒粗大、组织方向性明显等问题制约了该技术的发展。超声冲击处理作为一种强化手段,因其能够有效改善增材制造金属制件应力状态、细... 详细信息

增材制造作为一种快速发展的先进技术已在制造业领域得到广泛应用,但在金属制件增材制造过程中存在的晶粒粗大、组织方向性明显等问题制约了该技术的发展。超声冲击处理作为一种强化手段,因其能够有效改善增材制造金属制件应力状态、细化组织并提高其综合性能等特点而得到认可。本文从超声冲击在金属增材制造过程中对组织的作用机制和强化机理出发,总结了基于表面塑性变形实现增材制造强化的理论观点及局限性,阐述了超声冲击和增材制造复合作用下的组织细化机理和柱状晶向等轴晶转变机制,最后提出了超声冲击辅助金属增材制造强化理论建立过程中仍需进行深入研究的问题及建议。

关键词：超声冲击处理增材制造强化机制组织转变机理

Phase prediction for high-entropy alloys using generative adversarial network and active learning based on small datasets

在线全文

学校读者我要写书评

暂无评论

Science China(Technological Sciences) 2023年第12期66卷 3615-3627页

作者： CHEN Cun ZHOU HengRu long weimin WANG Gang REN JingLi Henan Academy of Big Data School of Mathematics and StatisticsZhengzhou UniversityZhengzhou 450001China State Key Laboratory of Advanced Brazing Filler Metals and Technology Zhengzhou Research Institute of Mechanical EngineeringZhengzhou 450001China Institute of Materials Shanghai UniversityShanghai 200444China

In this paper,a new machine learning(ML)model combining conditional generative adversarial networks(CGANs)and active learning(AL)is proposed to predict the body-centered cubic(BCC)phase,face-centered cubic(FCC)phase,and BCC+FCC phase of high-entropy alloys(HEAs).Considering the lack of data,CGANs are introduced for data augmentation,and AL can achieve high prediction accuracy under a small sample size owing to its special sample selection ***,we propose an ML framework combining CGAN and AL to predict the phase of *** arithmetic optimization algorithm(AOA)is introduced to improve the artificial neural network(ANN).AOA can overcome the problem of falling into the locally optimal solution for the ANN and reduce the number of training *** AOA-optimized ANN model trained by the AL sample selection strategy achieved high prediction accuracy on the test *** improve the performance and interpretability of the model,domain knowledge is incorporated into the feature ***,considering that the proposed method can alleviate the problem caused by the shortage of experimental data,it can be applied to predictions based on small datasets in other fields.

关键词： high-entropy alloys phase prediction machine learning conditional generative adversarial networks active learning

Metabolic assessement of spleen infiltration by non-Hodgkin lymphoma using ^(18)F-FDG PET/CT:Preliminary clinical results

在线全文

学校读者我要写书评

暂无评论

Nuclear Science and Techniques 2009年第4期20卷 235-242页

作者： SUN long PAN weimin LUO Zuoming WEI Jihong ZHAO long WU Hua Minnan PET Center and Department of Nuclear Medicine No.1 Hospital of Xiamen Fujian Medical University Xiamen 316003 China

18F-FDG PET/CT was used for evaluation of spleen infiltration in patients with B-cell non-Hodgkin lymphoma(NHL).Five patients with histological diagnosed B-cell NHL underwent1 8F-FDG PET/CT *** integrated PET/CT image,spleen infiltration was considered when PET images revealed a discrete margin of solid splenic masses or diffuse lesion of spleen with higher maximum standardized uptake value(SUV) greater than those of normal liver *** images demonstrating a positive splenic index(>480 mL)or focal hypodensities were classified as positive for spleen *** the patients underwent systemic ***1 8F-FDG PET and CT results were compared with final *** patients had spleen infiltration originating from B-cell NHL at final *** diagnoses,which were confirmed by clinical and CT(n=3) or1 8F-FDG PET/CT(n=1) follow-up in 4 patients and biopsy of 1 *** integrated PET/CT image,1 8F-FDG PET was true-positive in all 5 patients with spleen *** was true-positive in 4 of the 5 patients with spleen infiltration and false-negative in 1 patients (spleen infiltration without morphology changes).The accuracies of1 8F-FDG PET and CT for evaluating the spleen infiltration were 100% and 80% at staging,*** preliminary results suggested metabolic imaging of1 8F-FDG PET/CT may be helpful in the diagnosis of spleen infiltration in B-cell NHL *** patients may benefit from1 8F-FDG PET/CT in diagnosis,when spleen infiltration without morphology changes,which may not be diagnosed exactly by conventional image.

关键词： SUV ^18F-FDG PET/CT 能级原子核物理学

Wettability and joining of SiC by Sn-Ti: Microstructure and mechanical properties

在线全文

学校读者我要写书评

暂无评论

Journal of Materials Science & Technology 2020年第5期40卷 15-23页

作者： Wei Fu Xiaoguo Song Ruichen Tian Yuzhen Lei weimin long Sujuan Zhong Jicai Feng State Key Laboratory of Advanced Welding and Joining Harbin Institute of TechnologyHarbin 150001China Shandong Provincial Key Laboratory of Special Welding Technology Harbin Institute of Technology at WeihaiWeihai 264209China State Key Laboratory of Advanced Brazing Filler Metals and Technology Zhengzhou Research Institute of Mechanical EngineeringZhengzhou 450001China

Reliable Si C/Sn-Ti/Si C joints were obtained by brazing(950?C/10 min)and soldering(250?C/2 min)following premetallization depend on the wettability of Sn-Ti on Si *** microstructures of Sn-Ti/Si C interface were characterized by scanning electron microscopy,X-ray diffraction and transmission electron microscopy,and the mechanical properties of joints were evaluated by shear *** Ti enhanced the wettability of Sn on Si C with the decrease of contact angle from 150?to 20?.Ti direct reacted with Si C to produce Ti C and combines with released Si forming *** lower Ti concentration per contacting area in brazing and metallization,compared to wetting,resulted in defective bonding of Sn-Ti/Si C and few amounts of interfacial products(thin Ti C layer or partial covered Ti C layer with Ti5Si3).All of the Si C/Si C joints possess a similar shear strength of 27–32 MPa and rupture through?-Sn matrix in ductile fracture.

关键词： Microstructures Wettability Brazing Metallization SiC Sn Ti