环境湿度对铸铝合金超声疲劳裂纹扩展速率的影响研究

摘要

Several fatigue crack growth tests on a cast aluminum alloy (A356-T6)were performed herein under different frequencies and humidity levels.The experimented results show that ultrasonic fatigue in dry air and in distilled water have lowest and highest crack growth rate respectively.Con-ventional fatigue in lab air has almost same crack growth rate as ultrasonic fatigue in distilled water. Wei’s fatigue crack growth rate prediction model was modified,which could be used to predict the fa-tigue crack growth rate for peak aged cast aluminum alloy under different frequencies and humidity levels.%针对铸铝合金 A356-T6开展了不同环境湿度下的超声疲劳裂纹扩展试验和实验室环境湿度下的常规疲劳裂纹扩展试验。由试验结果可知，超声疲劳在干空气环境中的疲劳裂纹扩展速率最低，而在蒸馏水环境中的疲劳裂纹扩展速率最高。常规疲劳在实验室环境中的疲劳裂纹扩展速率和超声疲劳在蒸馏水环境中的疲劳裂纹扩展速率几乎一致。针对 Wei 建立的环境湿度对铝合金材料疲劳裂纹扩展速率预测模型进行了修正，得到了铸铝合金 A356-T6在任意环境湿度和试验频率下的疲劳裂纹扩展速率预测模型。