The flame tube of combustion chamber is the key structure of the aero-engine

and subjected to complex cyclic temperature load which will cause thermal fatigue. The thermal fatigue behavior of nickle based superalloy GH536 always used in flame tube was investigated. According to the characteristic load and structure of the flame tube

the specimen of a flat plate with a central hole and the thermal fatigue test were designed to study the crack initiation

crack propagation and thermal fatigue damage mechanism of the GH536 plate specimen under the thermal fatigue load condition. The study indicates: (1) the thermal fatigue cracks initiate transgranularly

develop and propagate intergranularly; (2) the crack propagation rate becomes faster and the crack initiation life becomes shorter with the increase of upper temperature in the thermal fatigue test. Thermal fatigue crack initiation life at 800℃ is 4.5 times of the crack initiation life at 900℃.