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Ultrasound-Assisted Solidifi cation of a Cu–Cr Alloy

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Acta Metallurgica Sinica(English Letters) 2022年第12期35卷 2082-2088页

作者： Siruo Zhang Huijun Kang Min cheng zongning chen Zhicheng Wang Enyu Guo Jiehua Li Tongmin Wang Key Laboratory of Solidifi cation Control and Digital Preparation Technology(Liaoning Province) School of Materials Science and EngineeringDalian University of TechnologyDalian 116024China Ningbo Institute of Dalian University of Technology Ningbo 315000China Institute of Casting Research Montanuniversitat Leoben8700LeobenAustria

Ultrasonic cavitation radiates huge power in a small solidifying bulk,leading to significant grain refinement,purification and homogenization of the final *** vibration has mostly been used for treating the solidification of light metals,but it is difficult to directly introduce ultrasonic vibration into copper alloy due to the lack of proper *** this work,we have used a Sialon ceramic sonotrode to propagate acoustic waves in a Cu-Cr alloy *** grain refinement and modification of primary Cr have been *** the ultrasound vibration treatment,the mechanical properties of the as-cast Cu-Cr alloy have been *** wear resistance of the Cu-Cr alloy has also shown enhancement with respect to the untreated alloy.

关键词： Cu-Cr alloys Microstructure Ultrasonic vibration Acoustic cavitation Solidification process

Grain nucleation and growth behavior of a Sn-Pb alloy affected by direct current： An in situ investigation

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Journal of Materials Science & Technology 2017年第10期33卷 1134-1140页

作者： Fenfen Yang zongning chen Fei Cao Rong Fan Huijun Kang Wanxia Huang Qingxi Yuan Tiqiao Xiao Yanan Fu Tongmin Wang Key Laboratory of Solidification Control and Digital Preparation Technology (Liaoning Province) School of Materials Science and Engineering Dalian University of Technology Dalian 116024 China School of Chemical Engineering Dalian University of Technology Dalian 116024 China School of Automotive Engineering Dalian University of Technology Dalian 116024 China Beijing Synchrotron Radiation Facility Institute of High Energy Physics Chinese Academy of Sciences Beijing 100049 China Shanghai Synchrotron Radiation Facility Shanghai Institute of Applied Physics Chinese Academy of Sciences Shanghai 201204 China

In situ synchrotron X-ray radiography was used to study the effect of direct current（DC） on the grain nucleation and growth of Sn-50 wt.%Pb alloy. The results showed that applying DC adequately during solidification could effectively enhance the grain nucleation and inhibit its growth. Imaging of comparative experiments with varying DC intensity indicated that the final grain size, determined by the competition between grain nucleation and growth, was sensitively dependent on the DC intensity. It was found that the average grain size was decreased from 1632 to 567 μm with DC density of 1.5 A/mm^2 compared to the case without DC. Beyond this value, raising the current density may cause a significant decrease in the nucleation rate, and thus lead to a coarsening of the grain structure.

关键词： Sn-Pb alloy Synchrotron X-ray radiography Solidification Microstructure Electric current

Mould taper optimization for continuous casting steels by numerical simulation

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China Foundry 2010年第1期7卷 61-67页

作者： Wang Tongmin Cai Shaowu Li Jun Xu Jingjing chen zongning Zhu Jing Cao Zhiqiang Li Tingju School of Materials Science and Engineering Dalian University of Technology Dalian 116024 China

A transient,two-dimensional,coupled finite element model was employed to simulate the solidification and shrinkage of continuous casting steels by means of *** the model,a gap-dependent heat transfer condition was introduced to modify the heat flux function,and the variations of material thermal properties,mechanical properties as well as the yield function with temperature were *** solidification and shrinkage processes of four round billets and two square billets were simulated by indirect coupled *** results show that carbon content,pouring temperature,casting speed and shape of billets have distinct influence on the solidification shrinkage of *** continuous parabolic tapers were designed and optimized according to the calculated shrinkage curves of billets.

关键词： mould parabolic taper shrinkage numerical simulation

A promising new class of plasticine: Metallic plasticine

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Journal of Materials Science & Technology 2018年第2期34卷 344-348页

作者： Yiping Lu Zhongyi Tang Bin Wen Gang Wang Shiwei Wu Tongmin Wang Yubo Zhang zongning chen Zhiqiang Cao Tingju Li Key Laboratory of Solidification Control and Digital Preparation Technology (Liaoning Province) School of Materials Science and Engineering Dalian University of Technology State Key Laboratory of Metastable Materials Science and Technology Yanshan University Laboratory for Microstructures Institute of Materials Shanghai University Key Laboratory of Materials Modification by Laser Ion and Electron Beams (Dalian University of Technology) Ministry of Education

Soft, malleable, and non-dry on exposure in air are the typical features for plain plasticine, which lead plasticine to be widely used in many industrial fields and our daily life. As a kind of clay, poorly elec- tric conductivity and thermal conductivity of plain plasticine seriously limit its applications. Therefore, synthesizing a kind of plasticine having metallic bond is of importance for extending its applications in some special cases, such as thermal-cooling medium, anti-static electricity, electromagnetic shielding, etc. Here, we report a novel GalnSnCdZn2 alloy, which exhibits similar behavior as compared to those of plasticine at near room temperature （30-40 ℃）, and a good electrical conductivity due to its nature of metal. This new GalnSnCdZn2 alloy can be called as metallic plasticine that contains the near-eutectic structure with low melting point and the other relatively high melting point phases. In this metallic plas- ticine, the near-eutectic structure with low melting point plays the same role as the oily ingredient in plain plasticine, dominating the plastic deformation, while the other relatively high melting point phases act as the stuffing like the CaCO3 in plain plasticine. The creation of metallic plasticine offers a general strategy for designing/preparing a new class of plasticine which possesses both the nature of metal and plasticine.

关键词： Metallic plasticine Alloy design Conductivity Microstructure design Microstructure

Micro Hierarchical Structure and Mechanical Property of Sparrow Hawk (Accipiter nisus) Feather Shaf

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Computer Modeling in Engineering & Sciences 2021年第5期127卷 705-720页

作者： Yichen Lu zongning chen Enyu Guo Xiangqing Kong Huijun Kang Yanjin Xu Rengeng Li Guohua Fan Tongmin Wang Key Laboratory of Solidification Control and Digital Preparation Technology(Liaoning Province) School of Materials Science and EngineeringDalian University of TechnologyDalian116024China School of Civil Engineering Liaoning University of TechnologyJinzhou121001China AVIC Manufacturing Technology Institute Beijing100024China Key Laboratory for Light-Weight Materials Nanjing Tech UniversityNanjing211816China

In this study,the real 3D model of the feather shaft that is composed of medulla and cortex is characterized by X-ray computer tomography,and the structural features are quantitatively *** and tensile tests are conducted to evaluate the mechanical performance of the feather shaft and cortex at different *** analysis of the 3D model shows that the medulla accounts for∼70%of the shaft volume and exhibits a closed-cell foam-like structure,with a porosity of 59%.The cells in the medulla show dodecahedron and decahedron morphology and have an equivalent diameter of∼30μ*** axial compression,the presence of medulla enhances the shaft ***,the combined effect of the medulla and cortex increases the buckling strength of the middle and distal shaft by 77%and 141%,respectively,compared to the calculated value of the shaft using linear mixed *** tensile properties of the cortex along the shaft axis are anisotropic because of the different fiber *** the fiber orientation gradually becomes uniform in the axial direction,the Young’s modulus and tensile strength of the cortex on the dorsal gradually increase from calamus to the distal shaft,and the fracture mode changes from tortuous fracture to V-shaped *** cortex on the lateral shows the opposite trend,that is the distal shaft becomes weaker due to fiber tangles.

关键词： Biomechanics feather shaft structure mechanical properties tomography

TiB_(2)对AlSi10MnMg合金压铸态组织及力学性能的影响

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特种铸造及有色合金 2024年第1期44卷 46-50页

作者：刘新华朱洪军陈明岚冯恩浪郝志刚陈宗宁郭恩宇康慧君方建儒王同敏大连理工大学材料科学与工程学院大连116024 大连科技学院大连116036 大连亚明汽车部件股份有限公司大连116041 大连理工大学宁波研究院宁波315016

基于TiB_(2)增强AlSi10MnMg合金压铸件,研究TiB_(2)颗粒对AlSi10MnMg合金铸件组织及力学性能的影响。结果表明,引入TiB_(2)降低了预结晶晶粒(ESCs)的尺寸,改善了富铁相的尺寸及形貌,AlSi10MnMg合金的屈服强度、抗拉强度和伸长率同步提... 详细信息

基于TiB_(2)增强AlSi10MnMg合金压铸件,研究TiB_(2)颗粒对AlSi10MnMg合金铸件组织及力学性能的影响。结果表明,引入TiB_(2)降低了预结晶晶粒(ESCs)的尺寸,改善了富铁相的尺寸及形貌,AlSi10MnMg合金的屈服强度、抗拉强度和伸长率同步提高。当TiB_(2)添加量为0.018%时,合金的屈服强度、抗拉强度和伸长率达到160.5 MPa、296.3 MPa和6.7%,较AlSi10MnMg合金分别提高了5.3%、11.5%以及115.9%。试样的拉伸断口观察发现有许多细小的韧窝和较少的撕裂棱,主要断裂机制为韧脆混合断裂。进一步增大TiB_(2)添加量,韧窝数量减少,断面处脆性断裂比例升高。

关键词： TiB_(2) 真空压铸显微组织力学性能

教师专业学习社群对幼儿教师组织沉默现象的影响

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武夷学院学报 2021年第11期40卷 97-102页

作者：杨佳陈宗宁福建幼儿师范高等专科学校福建福州350001

为深入了解教师专业学习社群对幼儿教师组织沉默现象的影响,研究者对来自某集团园的27位幼儿教师组成的教师专业学习社群开展为期4个月的行动研究。研究发现,教师专业学习社群能有效消除教师组织沉默现象;个人职务、教龄、召集人、学习... 详细信息

为深入了解教师专业学习社群对幼儿教师组织沉默现象的影响,研究者对来自某集团园的27位幼儿教师组成的教师专业学习社群开展为期4个月的行动研究。研究发现,教师专业学习社群能有效消除教师组织沉默现象;个人职务、教龄、召集人、学习方式等因素会影响教师话轮数,但教师专业学习社群能有效消除这些因素的影响;个人与他人原因也会导致教师组织沉默。基于研究结果,研究者提出运用教师专业学习社群消除教师组织沉默现象,平权可能是教研活动中急需推行的重要举措,关怀个体需要是撬动积极发言的支点等建议。

关键词：幼儿教师教师专业学习社群教师组织沉默

TiB_(2)/Al-Cu-Li复合材料时效析出及组织演变对力学性能的影响

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复合材料学报 2023年第12期40卷 6819-6829页

作者：张虎刘福源郭恩宇陈宗宁康慧君王同敏大连理工大学材料科学与工程学院辽宁省凝固控制与数字化制备技术重点实验室大连116024

研究了TiB_(2)/Al-Cu-Li复合材料T6工艺的微观组织演变和时效析出对力学性能的影响。通过气氛保护熔炼法制备了TiB_(2)/Al-Cu-Li复合材料。结果表明:在铸态合金的微观组织中,TiB_(2)颗粒和共晶相主要分布在晶界周围。均匀化处理后,大部... 详细信息

研究了TiB_(2)/Al-Cu-Li复合材料T6工艺的微观组织演变和时效析出对力学性能的影响。通过气氛保护熔炼法制备了TiB_(2)/Al-Cu-Li复合材料。结果表明:在铸态合金的微观组织中,TiB_(2)颗粒和共晶相主要分布在晶界周围。均匀化处理后,大部分共晶相回溶。轧制变形后,TiB_(2)颗粒沿着轧制方向被拉长,产生了大量位错。固溶处理削弱了轧制产生的Brass织构和S织构,回溶了轧制产生的析出相。在175℃温度下进行时效,欠时效过程中,δ’(Al_(3)Li)/β’(Al_(3)Zr)为主要析出相。随着时效时间的增加,到22 h峰时效时,T1相为主要析出强化相。通过位错强化和析出强化的共同作用,随时效时间增加,屈服强度和抗拉强度先上升后下降,延伸率持续下降。复合材料峰时效的极限抗拉强度为562.7 MPa,屈服强度为475.9 MPa,延伸率为4.5%。

关键词： Al-Cu-Li合金 TiB_(2) 时效析出轧制力学性能

Ca和Sn对Mg-4Zn合金组织和力学性能的影响

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特种铸造及有色合金 2022年第10期42卷 1263-1270页

作者：李国佳王冲郭恩宇康慧君陈宗宁王同敏大连理工大学材料科学与工程学院辽宁省凝固控制与数字化制备技术重点实验室辽宁大连116024

系统研究了Ca和Sn的添加对Mg-4Zn合金织构及力学性能的影响。结果表明,Ca显著细化合金组织并弱化织构。添加Sn导致MgSnCa相的生成,削弱了Ca的织构弱化效果。轧制态Mg-4Zn-0.2Ca合金具有最高的伸长率,达14.4%。同时加入Ca和Sn,显著提高... 详细信息

系统研究了Ca和Sn的添加对Mg-4Zn合金织构及力学性能的影响。结果表明,Ca显著细化合金组织并弱化织构。添加Sn导致MgSnCa相的生成,削弱了Ca的织构弱化效果。轧制态Mg-4Zn-0.2Ca合金具有最高的伸长率,达14.4%。同时加入Ca和Sn,显著提高了合金的强度,其中轧制态Mg-4Zn-0.2Ca-2Sn合金的强度最高,屈服强度和抗拉强度分别为255.4 MPa和295.3 MPa,但由于基面织构强度增加,伸长率明显降低。退火后,合金的强度下降,伸长率提高,这与合金中位错密度下降以及晶粒尺寸增大有关。

关键词： Mg-4Zn合金轧制退火力学性能