材料测试分析3.pdf

电子显微分析技术 绪论 多层次的物质结构 • 宏观：Macroscopic (0.1mm) – Structure elements on the scale visible with human eye. • 微观：Microscopic (0.1micron-0.1mm) – Grain or other mesoscopic objects consisting of a group of atoms and observable with a light microscope • 介观：Mesoscopic (1-100nm) – Structure between atomic and microscopic • 原子：Atomic (0.1-1 nm) – Arrangement of atoms in materials, electronic bondings • 亚原子：Subatomic (0.1 nm) – Electrons, protons, neutrons The scale of natural and man-made structures 眼见为实 Seeing is believing • 观测为实验科学之基础 – 百闻不如一见 • 但肉眼的分辨率和放大倍数有限，观测天体世界和微观世界需要仪器辅助 尺度与相应的研究工具 Length scale and investigating tools Nano Micron Human Grand Astronomical scale scale scale scale scale 10-10 -8 -6 -4 -2 0 2 4 106 108 1010 1012 10 10 10 10 10 10 10 Why Electronic Microscopy? Structure determines properties We have discussed crystal structure (x-ray diffraction) But consider now different level of structure Microstructure - also affects properties Grey cast iron (灰色生铁) - rather brittle Ductile iron - highly ductile Structure determines properties Cemented WC (碳化钨) Ferroelectric domains in BaTiO3 cutting tool Structure determines properties Microstructure - also can be art (美术) 电镜应用 Electric Microscopy Applications （1） Topography：原地形，地貌之意 形貌：the study of surface shape and features The surface features of an object or how it looks, its texture; direct relation between these features and materials properties Morphology：形态学，词态学 The shape and size of the particles making up the object; direct relation between these structures and m