The analysis on the low cycle fatigue behavior of a directionallysolidified superalloy with recrystallized surface layers
(0) Specimens of a directionally solidified superalloy with different shot peening pressurewere annealed at 1220℃ in vacuum condition to get recrystallized surface layers with differentmicro-structures.Low cycle fatigue tests of these specimens were performed at room temperature and400℃ by using an electrohydraulic load frame in the SEM system for real-time observation.Theinitiation and propagation of cracks were inspected and the influence of the micro-structure of therecrystallized layer on the material fatigue behavior was analyzed.The low cycle fatigue life of thespecimens depends mainly on the characteristics of the recrystallized layer.When the shot peeningpressure is lower,the recrystallized layer is thin and not integrated,and the fatigue life decreasesobviously in comparison with that of the specimen without recrystallized surface layer.When the shotpeening pressure increases,the recrystal grains are more integrated,and the fatigue life rises.Acomparison of the recrystallized layers between the blade surface and the specimen surface has beendone and it points that the incompact surface recrystal layer is very dangerous to gas turbine blades.
Directionally solidified superalloy recrystallized layer low cycle fatigue shot peening
H.J.Shi X.F.Ma D.W.Jia H.F.Zhang L.S.Niu
Failure Mechanics Laboratory,Department of Engineering Mechanics,School of Aerospace,Tsinghua University,Beijing 100084 China
国际会议
成都
英文
2008-08-04（万方平台首次上网日期，不代表论文的发表时间）