【摘要】 在三种厚度 70 75铝合金CCT试样随机谱裂纹扩展实验的基础上 ,对试样断口进行了精细的扫描电子显微镜分析。通过比较不同厚度试样在相同长度裂纹部位上同等放大倍数的金相照片 ,可以发现 ,试样的三维几何尺寸对裂纹扩展速率有着严重的影响 ,厚度越厚 ,则疲劳条带越稀 ,裂纹扩展越快。最后对机理进行了分析更多还原

【Abstract】 Based on the crack extension testing of 7075 Aluminum - Alloy CCT specimens in three kinds of thickness under random spectra, the fractures of the specimens are carefully analyzed by virtue of election scanning microscope in this paper. Through the comparison of the photomicrographs with the same magnification factor and at the same length of corresponding crack positions of specimens different in thickness, it is found that the three-dimensional geometry of specimen has a great effect on the crack growth rate; and the thicker the specimen , the wider the fatigue strap, and the faster the crack extends. By the end of this paper, the mechanism is analyzed.更多还原