摘要
本文研究了微观结构对718合金蠕变裂纹扩展行为的影响,对两种不同晶粒尺寸和三种不同碳化物分布的试样在650℃进行蠕变裂纹扩展试验。结果表明晶粒尺寸和碳化物结构显著影响蠕变裂纹扩展速率,蠕变裂纹扩展速率与晶粒尺寸成反比关系。碳化物成排且平行于裂纹试样的蠕变裂纹扩展抗力显著低于碳化物成排且垂直于裂纹的试样,更低于碳化物细小且均匀分布的试样。蠕变裂纹扩展速率与晶粒尺寸的反比关系归因于晶粒尺寸的增大使扩散路径增长,从而导致了微裂纹萌生和长大时间的增加。微观结构对718合金蠕变裂纹扩展行为的影响用蠕变裂纹扩展机理的三阶段模型给予了很好的解释。
The effect of microstructure on the creep crack growth behavior of Alloy 718 has been studied. The creep crack growth test of the specimens with the different grain size and carbide distribution has been carried out at 650℃. The results reveal that the crack growth rates strongly depends on grain size and carbide distributin, and the creep crack growth rates are reversely relative to grain size. The specimen with carbides in alignment and parallel to crack direction is much lower than that with carbide perpendicular to crack. The grain size also affects creep crack growth, which can be explained by the fact that the larger grain size leads to the longer time of microcrack initiation and growth.
出处
《航空材料学报》
EI
CAS
CSCD
1990年第A09期23-28,共6页
Journal of Aeronautical Materials
