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Journal of Contemporary Educational Research 2024年第4期8卷 29-34页

作者： Yipin Wan Jie Jia Tingting Gao xuding song School of Construction Machinery Chang’an UniversityXi’an 710018Shaanxi ProvinceChina Engineering College Xi’an Siyuan UniversityXi’an 710038Shaanxi ProvinceChina

This study aims to address the problems existing in the ideological and political education of postgraduate students,and combines the implementation of the mentor responsibility system to explore the role orientation,work content,and practical effects of mentors in the ideological and political education of postgraduate *** questionnaire surveys,interviews,and other research methods,the current situation of ideological and political education of postgraduate students under the mentor responsibility system is analyzed,and corresponding optimization strategies are proposed.

关键词： Mentor responsibility system Postgraduate students Ideological and political education Practical exploration

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泡沫铝夹芯板的三点弯曲疲劳性能

材料科学与工程学报 2024年第4期42卷 633-638页

作者：赵明凯王慧慧万一品宋绪丁长安大学道路施工技术与装备教育部重点试验室陕西西安710061

为探讨夹芯板结构准静态下的弯曲失效模式和疲劳性能,以304不锈钢为面板,7050铝合金基体闭孔泡沫铝为芯层,组成泡沫铝夹芯板结构。基于三点弯曲试验获得夹芯板结构损伤变形过程和静态峰值载荷。通过三点弯曲疲劳试验得到疲劳寿命和破坏... 详细信息

为探讨夹芯板结构准静态下的弯曲失效模式和疲劳性能,以304不锈钢为面板,7050铝合金基体闭孔泡沫铝为芯层,组成泡沫铝夹芯板结构。基于三点弯曲试验获得夹芯板结构损伤变形过程和静态峰值载荷。通过三点弯曲疲劳试验得到疲劳寿命和破坏形式,采用最小二乘法和极大似然法绘制夹芯板的S-N和P-S-N曲线,并进行对比分析。结果表明:夹芯板在静态加载时的弯曲失效与载荷-位移曲线相吻合;在疲劳加载时失效方式较为单一,90%的试件因芯层断裂而失效。夹芯板疲劳寿命随着面板厚度的增加而增加,当芯层密度从0.60 g/cm^(3)增加到0.73 g/cm^(3)时,疲劳寿命反而出现下降;当芯层密度为0.60 g/cm^(3),面板厚度为0.6 mm时,夹芯板结构对加载水平敏感度最低。研究结果为夹芯板结构工程应用提供了设计基础。

关键词：泡沫铝夹芯板面板厚度芯层密度疲劳性能

激光增材制造沉淀强化镍基高温合金热裂纹研究进展

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表面技术 2024年第7期53卷 1-14页

作者：李尧寇浩南李梦阳张阔刘源虢婷张凤英宋绪丁长安大学材料科学与工程学院西安710064 长安大学道路施工技术与装备教育部重点实验室西安710064

针对沉淀强化镍基高温合金中的裂纹现象,对比了2类热裂纹(即凝固裂纹和液化裂纹)的典型特征、形成位置和条件。从枝晶生长、元素偏析、强化相析出、固态相变和残余应力应变等角度,系统综述了热裂纹的形成机理和热裂纹敏感性影响因素。... 详细信息

针对沉淀强化镍基高温合金中的裂纹现象,对比了2类热裂纹(即凝固裂纹和液化裂纹)的典型特征、形成位置和条件。从枝晶生长、元素偏析、强化相析出、固态相变和残余应力应变等角度,系统综述了热裂纹的形成机理和热裂纹敏感性影响因素。在此基础上,从合金成分调控、工艺参数优化、基板预热以及热等静压处理等方面,概述了增材制造高温合金热裂纹调控和抑制的主要措施。最后,针对激光增材制造沉淀强化镍基高温合金热裂纹研究中存在的问题,提出了进一步研究和发展的建议,为实现无裂纹镍基高温合金的增材制造提供了参考。

关键词：激光增材制造沉淀强化镍基高温合金开裂机理热裂纹敏感性裂纹抑制

Effects of Heat-treatment on Crystallization and Wear Property of Plasma Sprayed Fe-based Amorphous Coatings

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Journal of Wuhan University of Technology(Materials Science) 2013年第4期28卷 643-646页

作者：姜超平 XING Yazhe HAO Jianmin song xuding School of Materials Science and Engineering Chang'an University Key Laboratory of Road Construction Technology and Equipment MOE Chang'an University

The Fe-based amorphous coatings were produced by air plasma spraying. The as-sprayed coatings were heat-treated at the temperature of 573, 873, and 1 023 K, respectively. The crystallization and wear behavior of the heat-treated amorphous coatings were investigated. It was found that the amorphous- nanocrystalline transformation appeared when the as-sprayed coatings were treated at 853 K. The crystallization process had completed and a coating with microcrystallines was formed when the treatment temperature reached 1 023 K. The resultant amorphous and nanocrystalline composite coatings exhibited superior wear resistance compared to crystalline coating. It is attributed to fine grain strengthening of formed nanocrystallines.

关键词： amorphous air plasma spraying crystallization heat-treatment

Spheroidization behavior of dendritic b.c.c. phase in Zr-based β-phase composite

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China Foundry 2013年第2期10卷 99-103页

作者： Sun Guoyuan Li Ping Chen Wei song xuding School of Mechanical Engineering North China University of Water Conservancy and Electric Power School of Mathematics and Information Science North China University of Water Conservancy and Electric Power Department of Mechanical Engineering Concordia University Key Laboratory of Road Construction Technology and Equipment MOE Chang'an University

The spheroidization behavior of the dendritic b.c.c, phase dispersed in a bulk metallic glass （BMG） matrix was investigated through applying semi-solid isothermal processing and a subsequent rapid quenching procedure to a Zr-basedβ-phase composite. The Zr-based composite with the composition of Z%62Ti138NbsoCuegNi5.6Be125 was prefabricated by a water-cooled copper mold-casting method and characterized by X-ray diffraction （XRD） and scanning electron microscope （SEM）. The results show that the composite consists of a glassy matrix and uniformly distributed fine dendrites of theβ-Zr solid solution with the body-centered-cubic （b.c.c.） structure. Based on the differential scanning calorimeter （DSC） examination results, and in view of the b.c.c.β-Zr to h.c.p, α-Zr phase transition temperature, a semi-solid holding temperature of 900 ℃ was determined. After reheating the prefabricated composite to the semi-solid temperature, followed by an isothermal holding process at this temperature for 5 min, and then quenching the semi-solid mixture into iced-water; the two-phase microstructure composed of a BMG matrix and uniformly dispersed spherical b.c.c.β-Zr particles with a high degree of sphericity was achieved. The present spheroidization transition is a thermodynamically autonomic behavior, and essentially a diffusion process controlled by kinetic factors; and the formation of the BMG matrix should be attributed to the rapid quenching of the semi-solid mixture as well as the large glass-forming ability of the remaining melt in the semi-solid mixture.

关键词： bulk metallic glass composite semi-solid isothermal processing spheroidized microstructure

Effect of casting technology on microstructure and phases of high carbon high speed steel

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China Foundry 2011年第2期8卷 197-201页

作者： Zhang Tianming Wang Qinjuan song xuding Fu Hanguang . School of Engineering Machinery Chang＇an University Xi＇an 710064 Shaanxi China Fujian Communication Technology College Fuzhou 350007 Fujian China School of Materials Science and Engineering Beijing University of Technology Beijing 100124 China

The as-cast microstructures of high carbon high speed steels （HC-HSS） made by sand casting, centrifugal casting and electromagnetic centrifugal casting, respectively, were studied by using of optical microscopy （OM） and D/max2200pc X-ray diffraction. The results show that the microstructure of as-cast HC- HSS is dominated by alloy carbides （W2C, VC, Cr7C3）, martensite and austenite. The centrifugal casting and electromagnetic centrifugal casting apparently improve the solidification structure of HCoHSS. With the increase of magnetic intensity （B）, the volume fraction of austenite in the HC-HSS solidification structure increases significantly while the eutectic ledeburite decreases. Moreover, the secondary carbides precipitated from the austenite are finer with more homogeneous distribution in the electromagnetic centrifugal castings. It has also been found that the lath of eutectic carbide in ledeburite becomes finer and carbide phase spacing in eutectic ledeburite increases along with the higher magnetic field strength.

关键词： high carbon high speed steel electromagnetic centrifugal casting solidification structure phase

Mechanical Characterization of Close Cell Aluminum Foams Reinforced by High Voltages Electro-deposition

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Journal of Wuhan University of Technology(Materials Science) 2019年第3期34卷 541-548页

作者： XU Yiku YANG Lei song xuding CHEN Yongnan PENG Xuan CHEN Yunzhou HAO Jianmin LIU Lin School of Material Science and Engineering Chang'an UniversityXi'an710064China Key Laboratory of Road Construction Technology and Equipment MOEChang'an UniversityXi'an710064China State Key Laboratory of Solidification and Processing Northwestern Polytechnical UniversityXi'an 710072China

The parameters for the electro-deposition of Cu were optimized in order to increase the compressive properties of close cell aluminum. Different values of deposition voltages and times were considered to vary the amount of deposited Cu. The surface morphology of the coating was observed by SEM and the compressive properties were evaluated by MTS. The results show that the coating is more homogeneous and compact with increasing voltage in a certain range, and beyond which, the coating quality decreases apparently. The reason is dedicated to the discharge rate of Cu2+ and nucleus formed in unit time. The compression results show three experienced stages: elastic deformation stage, collapse deformation stage and densification stage. After the electro-deposition of Cu, the elasticity modulus is increased obviously and the platform stress is also increased. Under the same strain, the stress of the aluminum foam with coating is reinforced comparing with the aluminum foam without coating. Furthermore, the platform area is widened apparently. In addition, Cu-SiC nanocomposite coatings are electrodeposited in alumium foams for further improving the mechanical characterization.

关键词： aluminum foam electro-deposition mechanical characterization

Effect of Laser Remelting on the Microstructure and Corrosion Resistance of Plasma Sprayed Fe-based Coating

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Journal of Wuhan University of Technology(Materials Science) 2015年第4期30卷 804-807页

作者：姜超平 WANG Junxing HAN Jianjun LU Yuan XING Yazhe CHEN Yongnan song xuding School of Materials Science and Engineering Chang'an University Key Laboratory of Road Construction Technology and Equipment MOE Chang'an University Xi'an Special Equipment Inspection Institute

Fe-based amorphous and nanocrystalline coatings were fabricated by air plasma spraying. The coatings were further treated by laser remelting process to improve their microstructure and properties. The corrosion resistance of the as-sprayed and laser-remelted coatings in 3.5wt% NaC1 and 1 mol/L HCI solutions was evaluated by electrochemical polarization analysis. It was found that laser-remelted coating appeared much denser than the as-sprayed coating. However, laser-remelted coating contains much more nanocrystalline grains than the as-sprayed coatings, resulting from the lower cooling rate in laser remelting process compared with plasma spraying process. Electrochemical polarization results indicated that the laser-remelted coating has great corrosion resistance than the as-sprayed coating because of its dense structure.

关键词： plasma spraying coating laser remelting corrosion

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粉末床熔融式增材制造钛合金研究进展及应用

中国有色金属学报 2024年第9期34卷 2831-2856页

作者：毛雅梅赵秦阳耿纪华刘燮陈永楠张凤英徐义库宋绪丁赵永庆长安大学材料科学与工程学院西安710064 长安大学工程机械学院西安710064 西北有色金属研究院西安710016

钛及其合金的粉末床熔融式(PBF)增材制造技术因具有定制制造、成本节约和时间优化等优势,在航空以及生物医学领域备受关注。但在PBF制造钛合金时,多种因素如热导率低、热积累、氧化敏感性及快速冷却引起的热应力共同导致成形件缺陷、组... 详细信息

钛及其合金的粉末床熔融式(PBF)增材制造技术因具有定制制造、成本节约和时间优化等优势,在航空以及生物医学领域备受关注。但在PBF制造钛合金时,多种因素如热导率低、热积累、氧化敏感性及快速冷却引起的热应力共同导致成形件缺陷、组织差异、性能不稳定与质量参差不齐等问题。因此,本文通过调研PBF技术中的激光粉末床熔融(Laser powder bed fusion,L-PBF)和电子束粉末床熔融(Electron beam powder bed fusion,EB-PBF)技术原理,讨论PBF增材制造钛合金微观组织特征、力学性能、耐腐蚀性能、耐磨损性能与生物相容性的特点;同时,聚焦成形过程中的缺陷形成机理及影响,提出缺陷消除方法;最后,展望两种技术的未来发展方向,为促进创新钛合金增材制造提供新的研究思路。

关键词：钛合金增材制造粉末床熔融微观组织性能缺陷应用

一种四次NURBS曲线反求控制顶点方法及应用

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仪器仪表学报 2020年第11期41卷 270-277页

作者：赵晓运宋绪丁长安大学道路施工技术与装备教育部重点实验室西安710064 台州学院航空工程(智能制造)学院台州318000

用提高方程阶次的方法,可以光顺和高效地反求复杂的自由型曲线曲面。基于B样条方法和贝齐尔方法逐步线性递推的性质和联系,推出了NURBS曲线插值控制顶点反求的一般算法表达式。结合边界条件,详细给出了一种四次NURBS曲线插值控制顶点反... 详细信息

用提高方程阶次的方法,可以光顺和高效地反求复杂的自由型曲线曲面。基于B样条方法和贝齐尔方法逐步线性递推的性质和联系,推出了NURBS曲线插值控制顶点反求的一般算法表达式。结合边界条件,详细给出了一种四次NURBS曲线插值控制顶点反求的矩阵方程和配套算法公式。通过对涡轮增压器叶轮叶片双四次NURBS曲面的逆向重构,并将该构造曲面与双三次的构造曲面进行数据对比分析,四次构造曲线的曲率比对应的三次构造曲线的曲率,减少了36.20%;四次构造曲面高斯曲率的最大值比三次的减少了2.04%,最小值减少了99.55%,曲面的光顺性得到明显提高。研究结果证实了该矩阵方程和配套算法公式的可行性和正确性。研究结论可为工程实践中,对复杂的自由型曲线曲面的逆向重构和数字化制造,提供有效的支持和借鉴。

关键词：控制顶点反求 NURBS曲线插值递推算法叶片曲面重构