7075高强度铝合金操作杆断裂失效分析

Fracture Failure Analysis of 7075 High-Strength Aluminum Alloy Operating Rod

【目的】高压开关设备断路器试验样机内部高强度铝合金操作杆在特殊机械故障模拟试验过程中发生断裂,需要查明7075高强度铝合金操作杆断裂失效原因。【方法】利用宏观观察、化学成分分析、硬度测试、金相检验、扫描电镜断口分析等失效分析法对该操作杆断裂原因进行分析。【结果】研究发现,该操作杆的断口表面主要呈辉纹特征,属疲劳断裂。【结论】7075高强度铝合金操作杆断裂失效是由硬度偏低、强度不足造成的,当操作杆在模拟试验累计动作时萌生疲劳裂纹,最终导致操作杆发生裂纹的扩展和断裂。

[Purposes] The reason of fracture of 7075 high-strength aluminum alloy operating rod in the circuit breaker test prototype of high-voltage switchgear broke during a special mechanical failure simulation test needs to be discovered.[Methods] Failure analysis methods such as macroscopic observation,chemical composition analysis,hardness test,metallographic examination,SEM fracture analysis were used to analyze the fracture causes.[Findings] the fracture surface of the manipulator was characterized by striations and belonged to fatigue fracture.[Conclusions] the fracture failure of 7075 high strength aluminum alloy manipulator is due to its low hardness and insufficient strength.When the manipulator is subjected to the accumulative action of the simulated test,fatigue cracks appear,finally,crack propagation and fracture occurred in the manipulator.