TC25钛合金四级压气机盘失效分析

Failure Analysis of 4th Compressor Disk of TC25 Titanium Alloy

某型涡扇发动机在进行压气机转子低循环性能考核试验过程中四级压气机盘破裂,在设计和制造质量复查未见异常的基础上,围绕材料性能、组织、化学成份和失效件断口展开分析,除因零件的最终热处理状态与该材料的标准热处理制度不同,导致失效件在室温及500℃的断裂强度略低于技术条件要求外,其余均未见异常。综合分析认为:在振动应力、离心力等复杂应力状态下,在相同圆周上同时形成多处疲劳源,并向着五级盘方向疲劳扩展,制件失效与以节圆振动为主节径振动为辅的复合振动有关。

A 4th compressor disk in a fanjet ruptured during low-circle properties testing. Design and manutacture quality rechecking was carried out, and no abnormal problem was found. Then material properties, mierostructure, chemical eompostion and fracture surfaces of the failure parts were analyzed. Except that the fracture strength of the failure parts at room and 500 ℃ was slightly lower than technical requirement, which resuhed from the difference between the practical heat treatment and the standard heat treatment, no other abnormal phenomena were found. Based on comprehensive analysis, it is assumed that under the complex stress state with vibration stress, centrifugal force, etc, multiple fatigue crack sources formed at the circumference, and the cracks propagated toward the 5th compressor disk. The fracture was related to compound vibration of major pitch circle vibration and minor nodal diameter vibration.