Small Fatigue Crack Initiation and Propagation in Particulate Reinforced and Whisker Reinforced Aluminum Base Composites at High Temperature.
Small Fatigue Crack Initiation and Propagation in Particulate Reinforced and Whisker Reinforced Aluminum Base Composites at High Temperature.
复制标题
高温下颗粒增强和晶须增强铝基复合材料中小疲劳裂纹的萌生和扩展。
DOI：
10.2472/jsms.44.59
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发表时间：
1995
期刊：
影响因子：
--
通讯作者：
J. Mizutani
中科院分区：
文献类型：
--
作者：
M. Okazaki;T. Hagino;J. Mizutani
研究了两种铝基复合材料从疲劳小裂纹萌生到扩展的过程，并与An颗粒增强复合材料和SiCw(SiCw)增强6061合金复合材料的高温长裂纹扩展行为进行了对比。并与传统耐热铝合金AC8A的结果进行了比较。结果表明，两种复合材料的疲劳裂纹易从增强相AlN颗粒或SiCw高密度聚集的区域萌生。与一般多晶金属材料一样，两种复合材料在小裂纹扩展过程中也出现了一些值得注意的现象，即小裂纹扩展过程中长、小裂纹之间缺乏相似性：小裂纹在低于长裂纹门槛值应力强度因子范围内仍有扩展，且扩展速率高于长裂纹。研究还表明，在加固效果方面，小裂纹有时表现为与长裂纹相冲突的方式。这些实验证据表明了研究疲劳小裂纹扩展的重要性。
Successive process from fatigue small crack initiation to propagation in two kinds of aluminum base composite materials was studied in comparison with long crack growth behavior at high temperature: One is an AIN-particulate reinforced composite and the other is a SiC-whisker (SiCw) reinforced 6061 alloy composite. The results obtained were also compared with that of a traditional heat-resisting aluminum alloy, AC8A. It was shown that the fatigue crack in the both composite materials easily initiated from the region where the reinforcement phase, AIN particulate or SiCw, gathered with high density. Like to general polycrystalline metallic materials, some noteworthy phenomena, which indicate the lack of similitude between small and long cracks, were seen in the small crack propagation process in the both composites: the small cracks grew even at the lower stress intensity factor range than the long crack threshold, and they exhibited higher growth rates than the long cracks. It was also shown that with respect to the effect of reinforcement the small cracks sometimes behaved with conflicting manner to the long cracks. These experimental evidences indicate the importance of studies on small fatigue crack propagation.