论文部分内容阅读
本文以45号钢及 LC4铝合金为研究对象,探讨微动损伤机理及其对疲劳强度的影响。试验结果证实,微动损伤使上述材料的疲劳极限降低了30%～55%左右。微动损伤形貌的扫描电镜分析指出,损伤区内产生并聚集了大量的球形微粒,它们是由脱离基体的金属碎片在连续微动作用下被轧压成具有较高含氧量的微粒组成。微粒嵌入金属表面形成“微动斑”,这是导致疲劳裂纹萌生的重要原因。分析还发现,在微动疲劳寿命的1/5时,磨粒及损伤区内的氧化铁相对含量急剧增加,这与扫描分析中观察到的在试件疲劳寿命的1/5时,在损伤区周界出现破坏性裂纹大致相对应。
In this paper, 45 steel and LC4 aluminum alloy as the research object, to explore the mechanism of fretting damage and its impact on fatigue strength. The test results confirm that the fretting damage reduces the fatigue limit of the above materials by about 30% -55%. Scanning electron microscopy analysis of the fretting morphology revealed that a large number of spherical particles were generated and aggregated in the lesion region and were formed by the metal particles released from the matrix being pressed into fine particles having a high oxygen content by the continuous fretting action . Particles embedded in the metal surface to form “fretting spots”, which is an important reason leading to fatigue crack initiation. The analysis also found that the relative content of iron oxide in the abrasive grains and the damage zone sharply increased at 1/5 of the fretting fatigue life, which was the same as that observed in the scanning analysis at 1/5 of the fatigue life of the test piece. The perimeter of the district appears destructive crack roughly corresponding.