起落架缓冲器上支臂支座断裂分析

Fracture Analysis of Upper Arm Pedestal of Undercarriage Buffer

主起落缓冲器疲劳试验中,缓冲器上支臂支座断裂。通过对支座材料成分、硬度和金相组织检测分析,以及断口宏微观形貌观察、断口能谱分析等,研究断口的断裂特征和裂纹源产生、扩展、断裂过程。结果表明,该支座在摩擦产生的高温条件下,Cd2+渗入基体形成共晶体,从而产生疲劳源;在交变应力的作用下,疲劳源发生隔脆,形成裂纹源,裂纹扩展导致断裂。根据支座断裂原因及使用环境,建议调整该支臂的表面处理工艺,配合面可采用镀锌等工艺,或采用其他防腐蚀能力较强的超高强度钢。

During the fatigue test of the main undercarriage buffer,the upper arm pedestal of the buffer fractured.Through analyzing the chemical composition,hardness and metallographic structure of the pedestal material,the macro and micro morphology of the fracture surface and the energy spectrum of the fracture surface,the fracture characteristics,crack initiation,propagation and fracture process of fracture surface were studied.The results show that under high temperature caused by friction,cadmium ions infiltrated into the matrix to form eutectic,resulting in fatigue source.Under alternating stress,cadmium embrittlement occurred,leading to crack source,and then crack propagation led to fracture.According to the fracture cause and the service environment,it is proposed to adjust the surface treatment process of the arm.The cadmium plating process should not be used for the mating surface.It can be replaced by zinc plating process or other ultra-high-strength steels with strong corrosion resistance can be used.