排序方式: 共有55条查询结果,搜索用时 15 毫秒
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采用超声辅助铸造技术成功制造了TiC纳米颗粒增强2219铝基复合材料,并对其进行锻造和T6热处理.本文研究了TiC/AA2219纳米复合材料在5、10、20和30 N下的摩擦磨损性能.研究发现,引入大量的TiC颗粒(1.3 wt.%和1.7 wt.%)后,复合材料的硬度明显增加.在相同载荷下,纳米复合材料的摩擦系数随着... 相似文献
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分析了金属凝固过程中界面热传递的4个阶段及在各阶段热传递的机理,推导出界面热传递系数在各个阶段的表达式。通过分析文献实验数据,得出了在整个凝固过程中热传递系数与空气隙成反比的半径经验耦合表达式。 相似文献
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大量调查表明,城市环境噪声的主要来源是路面车辆的交通噪声,为此,一方面,许多国家都针对不同车辆制订了噪声允许标准,其趋势是要求愈来愈高,并且已列为衡量产品质量的一个综合指标.另一方面,寻找降低车辆行驶噪声的有效途径及其低噪声设计方法,一直是工程技术界的努力方向。 相似文献
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介绍了一种基于SPWM技术的铝电磁场快速铸轧变频控制系统,分析了系统的工作原理、硬件结构、软件结构及控制模式,并且对系统特性进行了试验研究。试验表明,此系统可以对电磁感应器产生的复合磁场进行控制,系统控制精度高、可靠性高,动态性能好,满足铝电磁场快速铸轧的基本要求。 相似文献
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电磁场快速铸轧技术要求辊套材料不仅具有高导热系数、高承载能力和高抗疲劳能力,而且要具有磁场控制能力,保证铸轧区足够的磁感应强度,达到细化晶粒、改善板坯组织性能的目的.本文从介质对电磁场的集肤效应、涡流效应以及磁场衰减的角度,研究辊套对铸轧区电磁场的影响. 相似文献
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Thermal contact conductance at continuous roll-casting interface 总被引:1,自引:0,他引:1
The effects of surface roughness, strain rate, friction coefficient and pressure on real contact area were analyzed based on the research of Stupkiewicz. The real contact area model taking account of the effect of friction and deformation of material was obtained. The model of contact conductance at the rolling interface was obtained by integrating the specific feature of heat transfer through the interface of continuous roll-casting. The results indicate that the real contact area increases obviously when the material is under yield, and the real contact area varies inversely with surface roughness, whereas it varies exponentially with friction coefficient, strain rate and pressure, and the power factor depends on strain rate. 相似文献
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电磁场快速铸轧技术要求辊套材料不仅具有高导热系数、高承载能力和高抗疲劳能力,而且要具有磁场控制能力,保证铸轧区足够的磁感应强度,达到细化晶粒、改善板坯组织性能的目的.本文主要从介质对电磁场的集肤效应、涡流效应、磁场衰减以及屏蔽效应的角度,研究辊套对铸轧区电磁场的影响. 相似文献
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Influence of cerium on microstructures and mechanical properties of Al-Zn-Mg-Cu alloys 总被引:1,自引:0,他引:1
Effect of element cerium (Ce) on microstructure and mechanical properties of Al-Zn-Mg-Cu alloys has been investigated by transmission
electron microscopy (TEM), scanning electron microscopy (SEM), differential scanning calorimetry (DSC) and hardness test.
The results show that addition of Ce can remarkably refine the as-cast grains and eutectic microstructure. A transformation
from Mg(Zn,Cu,Al)2 phase to Al2CuMg phase is observed during homogenization. Furthermore, the Ce addition introduces changes in the precipitation process
and consequently in the age-hardening behavior of the alloy. Microstructural measurements reveal that the addition of Ce promotes
the precipitation of η′ phase, but it also partly retards the precipitation of GP zones. The density of precipitates decreases in a certain degree
and rod-like η′ precipitates increase when Ce content is from 0.2% to 0.4% (mass fraction). 相似文献