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The effect of heat treatment on microstructure of the melt-spun Mg-7Y-4Gd-5Zn-0.4Zr alloy

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Journal of Magnesium and Alloys 2016年第2期4卷 99-103页

作者： Ke liu wenbo du shubo li zhaohui wang College of Materials Science and Engineering Beijing University of TechnologyBeijing 100124China

The microstructure evolution of the melt-spun Mg–7Y–4Gd–5Zn–0.4Zr alloy during annealing treatment has been investigated by using X-ray diffraction(XRD),optical microscope(OM),differential scanning calorimetry(DSC)and transmission electron microscope(TEM).The results indicated that two kinds of primary grains were contained in the melt-spun *** was the supersaturated magnesium matrix,and the other was the 18R-LPSO *** 18R-LPSO phase transformed into the 14H-LPSO phase during annealing treatment at 300 ℃ for 0.5 *** new precipitate of the 14H-LPSO phase was found at 300 ℃ for 5 *** of linear precipitates formed as well as some precipitate with quadrangular morphology in matrix at 500 ℃ for 0.5 *** melt-spun alloy displayed the highest hardness of 103 NHV after annealing treatment at 300 ℃ for 5 h.

关键词： Mg-RE alloy Melt-spun Microstructure LPSO phase

内置传感器的沥青混合料变形协调及损伤行为研究

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铁道科学与工程学报 2024年第6期21卷 2272-2283页

作者：李文博刘朝晖柳力赵华张允宝王观次长沙理工大学交通运输工程学院湖南长沙410114 湖南省交通运输厅交通建设造价管理站湖南长沙410029 岳阳路桥集团有限公司湖南岳阳414100

为揭示应变传感器与沥青混合料协同工作性能的演化规律,提高传感器实测数据的应用价值和环境适应性,基于数字图像关联技术和小梁直接拉伸试验,对内置传感器的沥青混合料试件开展多重受力模式下的应变响应研究,分析不同温度条件下传感器... 详细信息

为揭示应变传感器与沥青混合料协同工作性能的演化规律,提高传感器实测数据的应用价值和环境适应性,基于数字图像关联技术和小梁直接拉伸试验,对内置传感器的沥青混合料试件开展多重受力模式下的应变响应研究,分析不同温度条件下传感器与沥青混合料的变形协调性能;并利用四点弯曲试验下的声发射信号和数字图像特征,揭示内置传感器的沥青混合料结构损伤演化规律。研究结果表明:内置应变传感器的沥青混合料变形协调特性与荷载类型、大小及响应时间紧密相关,传感器应变响应具有强烈的温度敏感性,在30~50℃的环境中,传感器应变响应的精准度会急剧衰减,其测量平均绝对误差Eˉa和相对误差Eˉr可分别增大3.49~11.79倍和2.01~2.91倍。利用声发射能量信号准确地刻画了传感器与沥青混合料协同受力下的4阶段损伤演化特征,反映出温度作用会改变结构损伤形式向非稳定开裂的态势发展;不同温度下声发射RA和AF的分布特征表明,内置应变传感器的沥青混合料结构破裂模式受温度影响显著,呈现为拉-剪混合、剪切破裂为主的破裂机制,且随温度不断增大,剪切破裂持续增强,剪切事件由55.7%增长至84.4%,增幅达1.52倍。研究成果对实现内置应变传感器与沥青路面协同工作性能的合理评判,推进传感器技术深度赋能传统沥青路面结构提供参考。

关键词：沥青路面数字图像关联技术声发射特征应变传感器变形协调

Simultaneously Enhanced Thermal and Mechanical Properties of ZK60 Alloy Reinforced by Oriented Graphene Nanoplatelets

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Acta Metallurgica Sinica(English Letters) 2023年第12期36卷 1999-2012页

作者： Baohong Zhu Xian du Fanjing Meng Xuefeng Wu Ke liu shubo li zhaohui wang wenbo du Faculty of Materials and Manufacturing Beijing University of TechnologyBeijing100124China

The lamellar and orientational characteristics of graphene nanoplatelets(GNPs)are crucial for reinforcing metal matrix composites,particularly in terms of their thermal *** kinds of GNPs with plane sizes of 6µm and 80µm were respectively used as reinforcements in ZK60 alloy by powder *** oriented distribution of GNPs in the matrix was obtained using a double-pass hot extrusion process,i.e.,a stepped extrusion with two consecutive extrusion ratios(10:1 and 16:1).Reinforced with 0.05 wt%oriented GNPs(80µm),the composite exhibited a tensile yield strength of 257 MPa,ultimate tensile strength of 342 MPa,elongation of 24.7%,and notably enhanced thermal conductivity of 128.3 W(mK)−1 even with refined grain size compared to the ZK60 *** oriented GNPs in the matrix create a favorable path for efficient load and heat transfer,leading to the simultaneously enhancement of mechanical and thermal properties of the GNPs/ZK60 *** work is expected to broaden the application potential of GNPs as highly efficient reinforcements and provide a practical method for fabricating metal matrix composites.

关键词： Graphene Magnesium Orientation Thermal properties Mechanical properties

A review on magnesium alloys for application of degradable fracturing tools

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Journal of Magnesium and Alloys 2022年第10期10卷 2649-2672页

作者： Jian Sun wenbo du Junjian Fu Ke liu shubo li zhaohui wang Hongxing liang Faculty of Materials and Manufacturing Beijing University of TechnologyBeijing 100124China

The vulnerable corrosion resistance of Mg alloys is regarded as one of the main disadvantages restricting their application,while it can be used as an extraordinary specialty in some particular fields,such as petroleum exploitation and *** recent years,many Mg alloys with high corrosion rate and high strength have been developed for fracturing temporary plugging tools in the oil *** review briefly introduces the performance requirements of the degradable fracturing tools classified into mechanical and corrosion *** progress on corrosion behavior of degradable Mg-Al,Mg-Zn,Mg-RE alloys and Mg matrix composites is then summarized and ***,the factors influencing the degradation rate of Mg alloys are analyzed and divided into secondary phase,texture,dislocation,grain size and surface *** the summary,it can be found that addition of Ni or Cu to the degradable Mg alloys is a common and effective method to enhance the degradation rate due to increasing the amount of secondary phases and deteriorating the corrosion product *** the as-extruded degradable Mg alloys,grain size,texture and dislocation are the key factors affecting the corrosion rate under different processing *** expect this review is helpful for those who are working on developing Mg-based functional materials with superior degradation rate.

关键词： Review Mg alloys Degradable fracturing tools Corrosion rate Secondary phase

Effects of trace Ca/Sn addition on corrosion behaviors of biodegradable Mg-4Zn-0.2Mn alloy

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Journal of Magnesium and Alloys 2018年第1期6卷 1-14页

作者： wenbo du Ke liu Ke Ma zhaohui wang shubo li College of Materials Science and Engineering Beijing University of TechnologyBeijing 100124PR China

The effects of alloying elements of Ca/Sn on corrosion behaviors of the as-cast Mg-4Zn-0.2Mn alloy were investigated by immersion tests and electrochemical *** results indicated that the average corrosion rate value of the Mg-4Zn-0.2Mn-Ca alloy was∼0.31 mm/year in Hank’s physiological solution for 40 days,and corrosion resistance increased for the specimens containing Ca element rather than that containing Sn because of the higher breakdown potential value,lower current density and deactivated corrosion rate,which was ascribed to a formation of the uniformly distributed Mg-Zn-Ca ternary phase.

关键词： Mg-Zn-Mn alloy Corrosion behaviors Hank’s physiological solution Electrochemical test

Effect of microstructure evolution on mechanical property of extruded Mg-12Gd-2Er-1Zn-0.6Zr alloys

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Journal of Magnesium and Alloys 2015年第1期3卷 23-28页

作者： Kai Wen Ke liu zhaohui wang shubo li wenbo du College of Materials Science and Engineering Beijing University of TechnologyBeijing 100124PR China

The microstructure evolution of as-cast,as-extruded and peak-aged Mg-12Gd-2Er-1Zn-0.6Zr alloys were investigated by Optical Microscope(OM),X-ray Diffraction(XRD),Scanning Electron Microscope(SEM)and Transmission Electron Microscope(TEM).The mechanical performance was also tested by tensile test at room temperature in the present *** results indicated that the lamellar 14H-LPSO structure formed during the solid solution process at 793 K for 24 h,and also existed after hot extrusion *** dynamic recrystallization(DRX)occurred during hot *** DRXed fine grain size was∼5μ***,some un-DRXed grains contained LPSO structure had a roughly orientation along the extrusion *** tensile test result showed that the as-extruded alloy had a better elongation of 14%due to fine DRXed grain and fiber-like un-DRXed with LPSO structure attributed to the high *** of the precipitation of theβ′-phase,the ultimate tensile strength(UTS)and yield tensile strength(YTS)increased up to 415 MPa(UTS)and 374 MPa(YTS),respectively.

关键词： Mg-Gd-Er-Zn-Zr alloys Mechanical properties Dynamic recrystallization LPSO

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基于微波遥感的土壤水分反演估算研究进展

土壤学报 2024年第1期61卷 16-28页

作者：郑曼迪刘忠许昭辉李剑辉孙君龄中国农业大学土地科学与技术学院北京100193 农业农村部华北耕地保育重点实验室北京100193

土壤水分是地表和大气水热过程交换的重要纽带,对于农业生产、生态规划、水资源管理等具有十分重要的意义。微波遥感具有基本不受天气条件影响,具有较好探测植被覆盖下的土壤信息和土壤水分变化趋势等优势,成为目前遥感精确反演土壤水... 详细信息

土壤水分是地表和大气水热过程交换的重要纽带,对于农业生产、生态规划、水资源管理等具有十分重要的意义。微波遥感具有基本不受天气条件影响,具有较好探测植被覆盖下的土壤信息和土壤水分变化趋势等优势,成为目前遥感精确反演土壤水分的热点。本文整理了现有全球尺度的基于微波遥感的土壤水分产品;分析比较了土壤水分反演中主动微波遥感、被动微波遥感、主被动微波协同技术的原理、特点、适用范围和关键技术进展:主动微波遥感和被动微波遥感的优势分别在于高空间分辨率和高时间分辨率,高空间分辨率可以很好捕捉地表细微的空间信息特征,但囿于土壤水分与后向散射系数之间的复杂关系,特别是植被、地表粗糙度等对雷达后向散射系数的干扰,使得反演土壤水分的精度不高,因而根据现实情况选取不同散射模型以及利用多源数据协同是目前改善精度的研究热点。而高时间分辨率可以实现全球及大尺度下的土壤水分监测,但是很难满足小尺度或者小区域范围的实际研究需求,为了能使实测数据在空间上得以较好匹配,提出多种降尺度方法。结合以上两种微波遥感方式的优劣,依托更为丰富的数据源、相对成熟的观测技术来对两者进行融合以提取更多的水分信息,以提升反演精度或者获得长时间序列数据。在目前的方法中,土壤水分反演在小尺度下表现出良好的性能,但在全球尺度上会出现数据缺失、适用性不强、反演精度不高以及反演过程过于复杂等诸多问题,可以借助多种观测方式(多极化、多角度、多波段)、多时相重复观测、在原有模型上引入新的算法以及数据同化等方面着手进行改进,同时全球卫星导航系统(Global Navigation Satellite System,GNSS)中长期稳定、高时空分辨率的L波段微波信号在陆面遥感领域的快速发展也为我国北斗卫星导航系统(BeiDou Navigation Satellite System,BDS)的发展提供了借鉴,展现出在土壤水分反演方面的巨大潜力。

关键词：主被动微波遥感散射方式降尺度 GNSS-R

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地面瞬变电磁法对低阻薄层的分辨能力

地质科技通报 2024年第1期43卷 343-351页

作者：胡俭杨帆张池庞少东姚伟华张文波李建慧陕煤集团神木张家峁矿业有限公司陕西榆林719099 中煤科工西安研究院(集团)有限公司西安710077 中国地质大学(武汉)地球物理与空间信息学院武汉430074

瞬变电磁法现阶段的资料处理解释仍以一维反演为主,因此分析瞬变电磁法对薄层的分辨能力对于更好地发挥瞬变电磁法优势仍具有重要意义。采用基于Occam算法的一维反演,以100 m深度内10 m层厚的低阻薄层为例,开展了地面回线源瞬变电磁法... 详细信息

瞬变电磁法现阶段的资料处理解释仍以一维反演为主,因此分析瞬变电磁法对薄层的分辨能力对于更好地发挥瞬变电磁法优势仍具有重要意义。采用基于Occam算法的一维反演,以100 m深度内10 m层厚的低阻薄层为例,开展了地面回线源瞬变电磁法对低阻薄层分辨能力的定性和定量研究。数值结果表明:低阻薄层电阻率与背景电阻率差异越大,薄层反演电阻率和层厚越接近于真实值;反演电阻率极小值位置始终对应于薄层位置。低阻薄层电阻率与背景电阻率比值为1∶5,1∶10,1∶20,背景电阻率小于100Ω·m时,瞬变电磁法能够良好探测10 m薄层的最大埋深依次为40,50,80 m;背景电阻率为200Ω·m时,上述3个最大埋深依次为30,30,60 m。上述研究成果有助于优化瞬变电磁法野外工作参数设计和提高资料处理解释精度。

关键词：瞬变电磁法一维反演低阻薄层分辨能力

挤压态Mg-8Gd-1Er-0.5Zr合金的抗蠕变性能

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稀有金属材料与工程 2019年第2期48卷 545-551页

作者：李淑波李瑞静王朝辉刘轲杜文博北京工业大学北京100124

研究了挤压态Mg-8Gd-1Er-0.5Zr合金在不同温度(150～200℃)和应力(50～70MPa)条件下100h的蠕变行为。利用OM、TEM等手段观察了蠕变过程中的组织演变规律,并对蠕变机理进行了分析。结果表明,在本实验条件下,合金表现出优异的抗蠕变性能,... 详细信息

研究了挤压态Mg-8Gd-1Er-0.5Zr合金在不同温度(150～200℃)和应力(50～70MPa)条件下100h的蠕变行为。利用OM、TEM等手段观察了蠕变过程中的组织演变规律,并对蠕变机理进行了分析。结果表明,在本实验条件下,合金表现出优异的抗蠕变性能,所有的蠕变曲线均呈现出减速蠕变和稳态蠕变两个阶段;在150℃/50 MPa时稳态蠕变速率仅为6.48×10^(-11)s^(-1),蠕变量为0.007%;在200℃/50 MPa时稳态蠕变速率为4.26×10^(-9) s^(-1),蠕变量为0.226%;温度较低时(150℃)主要为扩散蠕变控制机制,温度较高时(175,200℃)蠕变机制以位错蠕变为主。蠕变过程中晶内析出的β′相与镁基体具有一定的位相关系:(020)β′//[10 10]Mg,[001]β′//[0001]Mg,阻碍位错运动,而晶界析出的β相可以钉扎晶界。二者协同作用,促进合金高温抗蠕变性能的提高。

关键词： Mg-8Gd-1Er-0.5Zr合金挤压抗蠕变性能蠕变机制析出相