杜娟.低温对铝合金在SSRT过程中裂纹萌生与扩展规律的研究[J].有色金属工程,2019,9(9):.
低温对铝合金在SSRT过程中裂纹萌生与扩展规律的研究
Study on Crack Initiation and Propagation of Aluminum Alloy during SSRT at Low Temperature
投稿时间:2019-03-12  修订日期:2019-04-10
DOI:
中文关键词:  低温  7A04铝合金  慢应变速率拉伸  电化学阻抗谱
英文关键词:low temperature  7A04 aluminum alloy  slow strain rate tensile  electrochemical impedance spectroscopy
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作者单位
杜娟 中国民航大学
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中文摘要:
      本文采用一种电化学阻抗谱的解析方法原位研究低温对7A04铝合金在慢应变速率拉伸过程(SSRT)中裂纹萌生与扩展规律的影响,采用扫描电子显微镜对断口形貌进行观察,并通过KramersKronig转换验证电化学阻抗谱实验数据的可靠性。结果表明:裂纹的萌生和扩展过程大致可分为氧化膜溶解、裂纹萌生、动态平衡、裂纹明显扩展四个阶段;温度的降低会改变断裂方式,表现为从混合断裂向脆性穿晶断裂发展;由常温向低温的变化可以有效抑制铝合金在SSRT过程中的裂纹萌生和扩展,具体表现为温度越低对裂纹萌生和扩展的抑制效果越不明显,其中-5℃时抑制效果最强。
英文摘要:
      In this paper, the effect of low temperature on crack initiation and propagation of 7A04 aluminum alloy during slow strain rate tension (SSRT) was studied in situ by using an analytical method of electrochemical impedance spectroscopy (EIS). The fracture morphology was observed by scanning electron microscopy (SEM), from which we can predict the fracture types of aluminum alloys, and the reliability of EIS experimental data was verified by KramersKronig transformation.The results show that the crack initiation and propagation process can be divided into four stages: oxide film dissolution, crack initiation, dynamic equilibrium and crack propagation. The change from normal temperature to low temperature can effectively inhibit the crack initiation and expansion of aluminum alloy during SSRT process. The specific effect is that the lower the temperature, the less obvious the inhibition effect on crack initiation and propagation, and the inhibition effect is the strongest at -5 °C. The decrease of temperature changes the fracture mode, which is manifested from mixed fracture to brittle transgranular fracture. The Kramers Kronig transformation show the validity of experimental data at different temperature.
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