【摘 要】
：
Polycrystalline cubic boron nitride was sintered under high temperature(1400℃)and high pressure(5.5 GPa)using an in situ synthesis method.The compo-sition,micr
【机 构】
：
College of Materials Science and Engineering,Guilin University of Technology,Guilin 541004,China
论文部分内容阅读
Polycrystalline cubic boron nitride was sintered under high temperature(1400℃)and high pressure(5.5 GPa)using an in situ synthesis method.The compo-sition,microstructure,relative density and mechanical properties of the polycrystalline cubic boron nitride(PcBN)with different contents of Gd2O3 were studied by means of X-ray diffraction(XRD),scanning electron microscopy(SEM)and energy-dispersive spectroscopy(EDS).The results show that the phases of TiB2,TiN,AlN,AlTi2N and GdB6 are formed through in situ synthesis of cBN-Al-Ti-Gd2O3 system.With the Gd2O3 content increasing,the relative density increases and mechanical properties of PcBN begin to increase and then decrease.Proper amount of Gd2O3 can advance the formation of TiB2 and improve the aspect ratio of TiB2.When Gd2O3 content is 1.0 wt％,the PcBN exhibits optimal compre-hensive mechanical properties,with a microhardness of 33.35 GPa and a flexural strength of 972.37 MPa.
其他文献
近年来,以卷积神经网络为主的深度学习模型在各种遥感应用中都显示出巨大的潜力。以加州帝国郡为研究区,以Landsat 8 OLI年内时序遥感影像计算时序植被指数NDVI、EVI、RVI以及TVI,组合后输入到构建的一维卷积神经网络模型,以实现作物的高精度精细分类。为了验证卷积模型的优越性,另搭建了基于递归神经网络及其变体的深度学习模型。结果表明:(1)引入其他时序特征后,能够有效地提高卷积神经网络的
小麦是我国主要的农作物之一,对于我国的经济发展有着重要意义。遥感技术经过不断发展,已成为提取小麦及长势研究的重要手段。利用高光谱珠海一号OHS-2A卫星、多光谱Sentinel-2A卫星以及MODIS等多源遥感数据,以雄安为研究区,采用支持向量机的方法进行小麦提取,结合野外实测数据利用混淆矩阵进行精度评价分析;分别对比小麦的两个重要生育期返青期和抽穗期,将小麦长势分为3个等级(按长势较好、长势持平
In present work,five novel europium complexes[Eu(L)3·Phen(2),Eu(L)3·Bipy(3),Eu(L)3·Neo(4),Eu(L)3·Biq(5)and Eu(L)3·Batho(6)]were synthesized,derived from[Eu
The surface of Tb0.3Dy0.7Fe2 alloys was mod-ified by microwave electron-cyclotron-resonance chemical vapor deposition(MW-ECR-CVD)and ion implantation technology
Hot deformation behavior of the annealed ZK61M magnesium alloy sheet was explored using tensile tests with strain rates varying from 0.001 to 0.030 s-1 in tempe
The morphology and kinetics evolution of the γ'(Ni3Al)phase during re-dissolution are studied in Ni-15 at％Al alloy,the changes of volume fraction and average pa
In this work,the impacts of pressure on the structural,mechanical,thermodynamic and electronic properties of typical Pt3M(M = Al,Co,Hf,Sc,Y,Zr)compounds were in
以内蒙古闪电河流域为研究区,基于Sentinel2光学遥感影像结合随机森林和支持向量机算法,采用3种方案:基于像元的分类方法、面向对象的分类方法及改进的基于像元分类与面向对象分割相结合的集成方法,对研究区内的农作物进行精细提取。结果表明:(1)基于随机森林采用基于像元的方法进行分类,所有地类的总体精度为97.8%,Kappa系数为0.974,表明随机森林算法可以有效地进行农作物提取。(2)改进的基
无人机平台成本低和灵活性高的优点可弥补传统遥感平台的缺陷,为农业遥感近地表数据获取提供有效途径。任何型号无人机搭载传感器进行数据采集时均有一定的观测几何,但无人机观测几何诱发的方向反射差异及其在后续应用中的潜在误差仍需深入分析。利用无人机采集典型扬花期水稻田样方多角度观测,探讨其样方级别的方向反射及可见光植被指数的方向特点。结果表明:红、绿、蓝三波段的方向反射率差异分别可高达30.17%、22.0
To study the effect of α phase morphology(equiaxed α(αE)/lamellar α(αL))on the in situ tensile behavior of TC21 alloy,the slip band,dislocation,crack initi