Application of the SEM to the Study of Metal Fractures

摘要

Fractography has been used as a destructive test to determine metal quality, grain size, and quality of heat treatment since the 16th Century. The science of fractography began in the late 1930s when fracture textures were first related to the phenomena of hydrogen embrittlement. An understanding of the four basic fracture modes and precipitating causes can result in a more thorough understanding of the cause of fracture and can lead to an appropriate solution. The emergence of the SEM as a metallurgical research tool has been due to the tremendous wealth of knowledge that the SEM has provided in the last 15 years. Four distinct types of failure: ductile failure, two types of brittle fracture (cleavage and inter granular), and fatigue failure show distinct types of fracture surface pattern. Although the light microscope may yield important information concerning the mechanism of failure, the SEM, with its high resolving power and great depth of field, is the instrument of choice when a full understanding of the fracture mode is required.