共查询到20条相似文献,搜索用时 31 毫秒
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Dr. Sophie Primig Harald Leitner Ernst Kozeschnik 《BHM Berg- und Hüttenm?nnische Monatshefte》2014,159(1):5-11
Precipitation hardening of structural high-performance materials is considered as one of the most important strengthening mechanisms. In alloys containing precipitate forming elements, a fine dispersion of nanometer-sized particles precipitates from a supersaturated solid-solution. The size, volume fraction, and number density of these precipitates can be controlled by elaborate thermo-mechanical processing or by thermal treatments. The Christian Doppler Laboratory “Early Stages of Precipitation” aims at establishing a deeper understanding of such precipitation processes in steels, nickel-base alloys, and refractory metals. The experimental part of the lab in Leoben focuses on the characterization of small precipitates by state-of-the art high-resolution methods such as atom probe tomography and transmission electron microscopy, by scattering techniques, and by thermal analysis. The modelling part in Vienna concentrates on the modelling of precipitation kinetics mostly within the framework of the scientific software “MatCalc”. The main objective of both parts is the comprehensive study of the microstructure-property relationship in order to develop particle strengthened alloys with improved mechanical properties. 相似文献
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四针状氧化锌晶须制备方法及其在复合材料中的应用 总被引:8,自引:0,他引:8
四针状氧化锌晶须 (T -ZnOw)是晶须家族中目前发现的唯一具有规整三维空间结构的四针状晶须。由于其独特的空间四针状结构 ,以及特有的半导体、压电、吸波等特性 ,除了用作复合材料的增强体外 ,该晶须还可作为结构材料、功能材料等 ,在国防、电子、化工、交通等领域发挥巨大的作用。本文简述了四针状氧化锌晶须的结构、特性、制备方法 ,以及作为填充剂在复合材料方面的应用 相似文献
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以同时具有介孔和微米级大孔的新型多级孔道Al_2O_3整体柱为载体,Ce,Zr为助剂,制备得到Pd/Al_2O_3整体式催化剂,研究了催化剂的超低浓度风排瓦斯甲烷催化燃烧的反应性能,并结合实验结果,对Pd/Zr/Al_2O_3催化剂上甲烷燃烧的催化反应路径进行了探索分析。研究结果表明:所合成的添加助剂Ce,Zr的Pd/Al_2O_3催化剂的超低浓度甲烷氧化低温活性较好,催化剂保留了载体原有的特殊微观结构,比表面积仍然较大,有利于提高催化剂的反应活性。其中助剂Zr的助催性能比Ce的高。推测Pd/Zr/Al_2O_3催化剂上甲烷氧化的催化反应路径为:在助剂Zr的作用下,吸附在Pd O—Pd活性位上的CH4分子中一个C—H键的强度被削弱,小于H与Pd O表面晶格中O原子的键合强度,从而导致一个H原子从CH_4分子中脱出,速控步骤完成后反应快速进行,生成CO_2和H_2O。 相似文献
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Heike Zacharias Johannes Arndt Dr. Sophie Primig 《BHM Berg- und Hüttenm?nnische Monatshefte》2014,159(7):296-297
The case-hardening steel 18CrNiMo7???6 is used for large gear wheels in wind turbines. To achieve the requirements for a wear resistant and tough material, the steel is carburized and case hardened at 980?°C for 80 h. During this heat treatment, grain growth occurs, which should be avoided by micro-alloying the steel with aluminium and niobium. These elements pin the grain boundaries in form of carbides and nitrides to reduce the grain growth. In this work the grain size stability of several micro-alloyed variants of the case-hardening steel 18CrNiMo7???6 under different heat treatment conditions was examined. For the microstructural characterization, light microscopy, scanning, and transmission electron microscopy as well as atom probe tomography were applied. 相似文献
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磷矿石中脉石成分对窑法磷酸工艺的影响 总被引:1,自引:0,他引:1
窑法磷酸工艺是一种不用硫酸,少用电的磷酸生产工艺,具有原料来源广泛,磷酸生产成本低的特点。本文详细讨论了磷矿石脉石中SiO_2,Al_2O_3,CaO,MgO,Fe对窑法磷酸工艺的影响,研究了不同类型磷矿石对窑法磷酸工艺的适应性,给出了试验和电子探针分析结果。 相似文献
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Mesoscopic structures must be determined in order to analyse the behaviour of inhomogeneous materials such as coal rock. In this study, a three-dimensional texture of coal rock is scanned by X-ray tomography images using CT system. The time-dependent fracturing behaviour of coal rock for dynamic damage test is then observed by mesoscope under uniaxial stress conditions. In order to determine the dynamic damage evolution process of coal rock, a meso-damage model is introduced, and a constitutive relationship is developed for coal rock subjected to dynamic uniaxial compression in three stages including (I) quasi-linear phase, (II) damage evolution stage and (III) damage accelerating fracture extension. The corresponding meso-mechanical damage mechanisms are investigated. 相似文献
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平面回转筛因其物料运动路线长,筛分效率高等特点广泛用于粮食、饲料、矿物及化工等行业中原料及成品的筛选、分级作业。平面回转筛由机架、筛箱、尾部支撑机构及驱动装置等部件组成。传统的设计方法是利用二维图形来表达三维信息,非常抽象且不便于修改。利用三维设计软件Pro/E对平面回转筛进行三维建模和虚拟装配,不仅简化了设计过程,而且可视性增强,大大提高了设计效率。 相似文献
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立式振动输送机及物料的运动研究 总被引:1,自引:0,他引:1
介绍了立式振动输送机的结构及工作原理。运用圆矢量、回转运动群和微分几何等理论对立式振动输送机及其物料的运动在三维空间内进行了分析和计算,并且给出了抛掷指数和输送速度等计算公式。 相似文献
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李保健 《有色金属(矿山部分)》2020,72(2):19-23
为了应对某矿山顶板岩层破碎、采场稳定性难以控制的工程特点,以现有矿山开采技术条件为基准,从待充填空区三维激光探测、充填材料的选择、充填浓度配比的优化、料浆的制作与输送、上向分层充填工艺的改进等角度对该矿充填采矿法进行优化。通过多环节的技术更新优化,有效降低了该矿山的资源浪费、财产损失以及安全生产事故隐患。本文对该矿上向分层充填采矿法的充填工艺和材料进行了详细阐述,以期对类似复杂工况条件的矿山起到一定的参考作用。 相似文献
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为了解决大尺度空间内复杂物体的形貌尺寸测量问题,提出了一种快速三维数字化精确测量的方法,该方法采用全局测量和终端测量相结合的方式,消除了大型工件整体尺寸大与局部空间复杂的矛盾。首先在分析线结构光测量原理的基础上,提出一种基于局域空间定位的手持式激光扫描测量方法,并构建测量数学模型;其次对手持测量头的空间姿态给出相应的数学建模过程;最后给出完备的组合式三维测量数学模型。该方法可用于各种大范围场景三维精确测量和重构,为三维实体资源快速重构数字化模型提供准确的理论依据。 相似文献
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利用超声波探测仪对土层注浆土体固结时间的变化进行了测试试验研究.土质为细砂和砂质土,浆液为水泥-水玻璃双液浆.根据波速随固结时间的变化规律得知,注浆4d后土体即可具有稳定的固结强度. 相似文献
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三维超声波声场建模仿真在无损检测中的应用 总被引:1,自引:0,他引:1
基于超声波探头辐射的三维超声场模型,利用MATLAB开发可视化窗口程序,显示出三维仿真结果,人机交互式改变影响声场的参数。有利于形象、直观地理解声场,为科研和工程实际中分析和研究超声探头的辐射声场,探头各项参数选取、检测信号的发射与接收、各种材料的超声探伤与评价等提供参考。 相似文献
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对四川旺苍石墨矿进行了工艺矿物学研究,查明了矿区内矿石的化学成分、矿物组成、主要矿物的嵌布特征,并对石墨的晶体结构特征进行了测定。结果表明,矿石中石墨主要呈脉状或细脉状与石英、云母相间分布,部分呈自形或半自形散布在脉石矿物中,不同层位石墨粒度大小区别较大。固定碳含量为23.73%~47.41%。酸法纯化后样品的Raman光谱分析显示,石墨的ID/IG比值为0.02~0.07,说明各样品中不含非石墨结构的碳类物质,且石墨晶体结构缺陷较少、三维晶体结构发育完善。判定该矿区石墨为晶质鳞片状石墨,且不含隐晶质石墨。 相似文献
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Christoph Lerchbacher Silvia Zinner Harald Leitner 《BHM Berg- und Hüttenm?nnische Monatshefte》2012,157(11):414-419
The modified stainless martensitic chromium steel X38CrMo16 offers excellent toughness, corrosion and wear resistance. The typical heat treatment of this steel consists of a hardening treatment followed by a more-step tempering procedure. Tempering causes the precipitation of secondary carbides, nitrides and carbonitrides which are responsible for the improved hardness at elevated temperatures. Experiments have shown that the behaviour in corrosion resistance varies within the temperature range commonly used for tempering this steel. The corrosion resistance reached a minimum at 540 °C until it increases again. For the microstructural investigations the samples have been tempered for shorter times and the minimum moved to 575 °C. At that temperature, significant chromium depletion zones in the size range of approximately 6 nm extent could be visualized by means of atom probe tomography. The chromium concentration decreased to 10 at% within these zones. Depletion zones could be shown for small nitrides as well as for larger carbides which were formed during tempering. The existence of these local anodic zones could be confirmed by TEM investigations. 相似文献
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以磷酸铁锂为正极活性材料, 采用直接混合法, 研究了添加质量分数为0.5%、1%和1.5%的石墨烯对锂离子电容器电化学性能的影响。利用扫描电子显微镜、X射线衍射分别对材料形貌、结构等进行了分析, 并比较了掺杂不同石墨烯的电极材料恒流充放电性能和循环性能。结果表明, 石墨烯是一种三维自支撑片状结构, 粉末材料是独立形成的, 并且不易团聚, 纳米磷酸铁锂颗粒分散均匀, 颗粒呈类球型状; 掺杂不同量的石墨烯对磷酸铁锂本身结构几乎没有影响; 掺杂1.5%石墨烯电极性能最好, 高倍率5C时, 放电比容量96 mAh/g, 容量保持率77%, 当恢复到0.1C时, 放电比容量是初始容量的95%, 循环500圈后容量保持率达92%, 阻抗最小,为0.3661 Ω。 相似文献