人造金刚石烧结体的磨料粒度配比研究

金刚石烧结体具有许多优异的物理机械性能。由于金刚石的硬度与弹性模量极高,在烧结时很难发生塑性变形。本文通过理想化模型,得到最佳粒度配比。对按照此配方制做的烧结体进行了磨耗比检测,结果表明磨耗比提高了37.08％。     

图像采集系统帧序列上缺陷像素的识别

给出了缺陷像素的定义。对由图像帧序列构成矩阵去除直流分量所得到的余量矩阵作主成分分解建立特征图像。对特征图像作方差分析并结合为像素所定义的Mahalanobis距离，建立起概率分布意义上的缺陷像素识别的数学模型。实验结果分析表明，在给定每帧图像所包含的像素数时，通过距离基准限及一个可调节常量的设置，该概率模型可以满足图像采集系统在不同精度要求下对包括图像采集帧上的瑕点、闪烁像素以及漂移像素等缺陷像素的识别。     

POD控制器在机房电力监控系统中的应用

机房电力监控系统在计算机机房的环境建设中是重要的组成部分。瑞士SAIA（思博）公司的PCD糸夕U产品，因为其强大的通讯功能、快速的CPU处理能力、友好的编程工具、开放的技术接口，被广泛的应用于机房电力监控系统中。本文结合一个具体案例阐述PCD控制器在机房电力监控系统中的应用。     

Predicting wear mechanisms of ultra-hard tooling in machining Ti6Al4V by diffusion couples and simulation

Conventional cemented carbide is recommended for machining Ti6Al4V. However, polycrystalline diamond (PCD) and polycrystalline cubic boron nitride (pcBN) also show promise. Demands for higher productivity accelerate diffusional dissolution and chemically driven wear mechanisms in these tool materials. This study investigates active wear mechanisms by studying the interactions between Ti6Al4V and PCD, pcBN, and cemented carbide tools in diffusion couples at temperatures from 900° to 1300°C. All tool materials suffered from diffusion to varying degrees, and different chemical reactions occurred. Titanium carbide with minor vanadium alloying (Ti,V)C reaction products act as diffusion barriers when using PCD and cemented carbide, while the reaction products acting as diffusion barrier in pcBN is (Ti,V)B₂. The presence of Mo and W in binder sites of pcBN reduces diffusional dissolution of cBN. Diffusion simulations agreed well with microscopy investigations and were enabled by the known temperature and pressure conditions of the static diffusion couples.     

车削硅铝合金活塞的PCD刀具刃磨及几何参数

通过使用不同刃磨质量的polycrystalline diamond(PCD)刀具车削加工硅铝合金活塞实验,阐述了PCD刀具刃磨质量及几何参数对硅铝合金活塞加工表面粗糙度的影响.实验结果表明:活塞加工表面粗糙度随着PCD刀具刃磨质量的提高而减小;在实际生产中,刀具的合理刃磨质量必须在高于刀具刃磨质量临界状态,根据工件加工表面粗糙度来确定;精车斯特尔WD615型活塞(材料为BH122A硅铝合金)外圆时,PCD刀具的刀尖圆弧半径rε的最佳范围值0.8 mm rε<3.5 mm;刀具的合理后角值为6°~9°.     

Investigation on Surface Roughness for Press－Finishing of Aluminium Alloy with PCD Sphere

ＩｎｖｅｓｔｉｇａｔｉｏｎｏｎＳｕｒｆａｃｅＲｏｕｇｈｎｅｓｓｆｏｒＰｒｅｓｓ－ＦｉｎｉｓｈｉｎｇｏｆＡｌｕｍｉｎｉｕｍＡｌｌｏｙｗｉｔｈＰＣＤＳｐｈｅｒｅ￥ＹＵＸｉｎｇｂｏ；ＷＡＮＧＱｉｎｇｃｈａｏ（余兴波，王庆超）（Ｄｅｐｔ．ｏｆＭｅｃｈａｎｉｃ...     

聚晶金刚石压痕行为的离散位错动力学仿真分析

依据位错理论,建立了聚晶金刚石(polycrystalline diamond,PCD)离散位错动力学-有限元耦合的压痕仿真模型。通过离散位错动力学仿真,获得了在微压痕作用下PCD的位错云图,揭示了金刚石微粉颗粒尺寸及颗粒体积分数对聚晶金刚石压痕特性的影响规律,并分析了聚晶金刚石的位错演化机制及其失效行为。研究结果表明:采用离散位错动力学分析方法能够准确描述PCD的位错运动过程,PCD微粉颗粒尺寸增加会增大晶体位错滑移程度,金刚石颗粒体积分数增加则导致位错形核密度增加,最终将引起聚晶金刚石材料断裂强度下降。将离散位错理论引入到为分析聚晶金刚石位错演化的行为中,将为研究PCD在切削刀具等工程应用中材料的失效行为提供理论基础。     

颗粒电荷测定在纸机生产中的应用

介绍了轻型印刷纸生产过程中,颗粒电荷测定在调整化工助剂用量、改善纸机抄造环境中的应用。     

The Role of Additive Manufacturing and Physiomimetic Computational Design for Digital Construction

The recent adoption of the term additive manufacturing (AM) to describe a broad range of digital ‘layer by layer’ fabrication techniques comes 20 years since its inception and more than 10 years since architectural practices engaged with the technology for making prototypes and models. Soon this technology will join existing CNC subtractive and formative processes within the volume and mass-market sectors, where design complexity and increased functionality result in competitive advantage. It is also about a decade since researchers proposed additive manufacturing for construction. Rupert Soar and David Andreen introduce here the different construction-scale additive manufacturing systems currently in development. If linked to physiomimetic computational design strategies, these technologies provide novel possibilities for addressing architecture's manufacturing challenges in the face of energy expenditure, material resources and environmental impact. Copyright © 2012 John Wiley & Sons, Ltd.     

Effect of controllable decomposition of MAX phase (Ti3SiC2) on mechanical properties of rapidly sintered polycrystalline diamond by HPHT

Sintered polycrystalline diamond (PCD) was prepared via high temperature and high pressure (HTHP) process using Ti₃SiC₂ and Si as the binder. The effect of decomposition of Ti₃SiC₂ on comprehensive properties of PCD was investigated at different temperatures. Results show that Si formed liquid phase infiltrated diamond surface at high temperatures to inhibit diamond graphitization and to reduce defects significantly. In addition, strong covalent bond of Si-diamond was generated, which increased the strength of PCD. At suitable temperature, Ti₃SiC₂ would partially decompose to TiC and SiC with high activity. Strong covalent bond of TiC and SiC also increased relative density and hardness of PCD, and residual Ti₃SiC₂ enhanced the toughness of PCD. At 1500 °C, the hardness and toughness of PCD reached 54.35 GPa and 8.6 MPa m^1/2, respectively, which are 19% and 82%, respectively, higher than PCD sintered at 1350 °C.