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采用扫描电镜同时观察断裂特征及其断口下的显微组织,这对在确定疲劳、断裂性质及断口形貌与显微组织之间关系的研究中具有重大的价值。由于扫描电镜对显微组织的分辨率远远高于光学显微镜的分辨率,并具有足够的焦深,因此这种同时观察有了可能。扫描电镜的出现,也促进了适合于这种同时观察的制样技术的发展。以往采用的方法是用一种适当的材料将试样断口保护起来,然后将试样沿垂直于断裂路程的平面切开,抛光和侵蚀。但该方法有二个缺点。1)在断口——金相截面的边缘处可能出现倒角,从而失去了某些所需的特征;2)为了不损坏断口,在去除镶嵌材料时需要特别小心。Shechtman曾提出一种
Simultaneous observation of the fracture characteristics and fracture microstructure with scanning electron microscopy is of great value in the study of the relationship between fatigue, fracture properties and fracture morphology and microstructure. Since SEM resolution of the microstructure is much higher than the resolution of the optical microscope, and has sufficient depth of focus, so this simultaneous observation is possible. The advent of SEM has also contributed to the development of sample preparation techniques that are suitable for this simultaneous observation. In the past, a suitable material was used to protect the fracture surface of the specimen and then the specimen was cut, polished and eroded along a plane perpendicular to the fracture path. However, this method has two disadvantages. 1) chamfering may occur at the edges of the fracture-metallographic section, losing some of the required features; and 2) extreme care needs to be taken when removing the mosaics in order not to damage the fracture. Shechtman has proposed one