高速列车车体铝合金抗应力腐蚀性能

摘要

为了确定高速列车常用5、6、7系列铝合金部件的安全可靠性,采用恒载荷方法和恒位移方法研究了其应力腐蚀开裂敏感性,对试样进行机械切口并预制疲劳裂纹,在施力点施加恒定载荷或恒位移后进行腐蚀试验.通过相同加载对比实验发现:3种系列铝合金中,7N01P-T4临界应力强度因子值低于11.238 MPa·m1/2,应力极限值低于224.3 MPa,抗应力腐蚀性能比5083P-H111、6005A-T6差,但均满足使用要求；应力腐蚀阴极反应而导致的氢脆在裂纹源区附近呈现典型的应力腐蚀特征,在疲劳区附近表现氢致开裂特征,与实际断口上直线沟槽分布状况相符.%In order to ensure the safety and reliability of the series 5,6 and 7 aluminum alloy components of high-speed trains,specimens were tested using constant loading technique and constant displacement technique for the stress corrosion cracking.Mechanical incisions and fatigue cracks were prefabricated on the samples,which were then tested by applying a constant load or constant displacement.Experimental results showed that the series 7N01P-T4 alloy,with a critical stress intensity factor K I scc of less than 11.238 M Pa· m1/2 and a limit stress of less than 224.3 MPa,underperforms the series of 5083P-H111 and 6005A-T6 in the stress corrosion resistance,but the three series of aluminum alloy all met the requirements.Typical characteristics of stress corrosion caused by hydrogen embitterment of catholic reaction were found near the crack source region,but the characteristics of hydrogen-induced cracking were found near the fatigue region,which was consistent with the distribution of straight-line trenches on the fracture.