DZ125定向凝固高温合金在不同状态下的超高周疲劳行为研究  

Ultra-high Cycle Fatigue Behaviors of Directionally Solidified Superalloy DZ125 Under Different Conditions

作　　者：顾玉丽[1] 陶春虎[1] 佘力[1] 何玉怀[1] 曲士昱[1] 

机构地区：[1]中航工业北京航空材料研究院航空材料检测与评价北京市重点实验室,北京100095

出　　处：《材料导报》2015年第10期108-113,共6页Materials Reports

基　　金：国家自然科学基金(11302212)

摘　　要：研究了常规热处理和长期时效状态的DZ125定向凝固高温合金在室温和700℃下的超高周疲劳特征及其差异。利用超声疲劳试验机测试了合金的超高周疲劳性能,采用扫描电镜研究了合金的疲劳断口特征,借助电子探针和纳米压痕测量仪分别测试了合金枝晶间和枝晶干的成分和弹性模量。结果表明:两种热处理制度下DZ125合金的枝晶间和枝晶干的弹性模量以及合金元素分配和偏析比差异不大;DZ125合金在700℃下的超高周疲劳性能低于室温,合金在室温下存在明显的频率效应,但在700℃下不存在频率效应;室温和700℃下,合金经过长期时效后的疲劳性能均有所降低,特别在700℃下合金性能降低得更多。室温下,DZ125合金的两种热处理制度的超高周疲劳裂纹均起源于试样的表面;700℃下,两种热处理制度的超高周疲劳裂纹均起源于试样的亚表面。The ultra-high cycle fatigue characteristics at room temperature and 700 ℃, respectively, of the di- rectionally solidified superalloy DZ125 with conventional and long-term aging heat treatment were studied. The ultra- high cycle fatigue properties of the DZ125 superalloy were measured using ultrasonic fatigue test machine, and the fa- tigue fracture characteristics were investigated using scan electron microscopy （SEM）. The elements distribution and elastic modulus in the dendritic arm and interdendritic region were tested respectively using electron probe micro-analy- sis （EPMA） and nano-indentation tester. The results showed that the differences of the element distribution and elas- tic modulus of conventional treated and long-term aged DZ125 superalloys in the dendritic arm and interdendritic region were slight. The ultra-high cycle fatigue properties of the alloys were lower at 700 ℃ than those at room temperature. The frequency effect is more obvious at room temperature than that at 700 ℃. The ultra-high cycle fatigue property of DZ125 superalloy decreased after long-term aging at room temperature ever more at 700 ℃. The fatigue cracks of the alloys with two heat treatments both originated from the surfaces of the specimens at room temperature, while from the subsurfaces of the specimens at 700 ℃.

关 键 词：定向凝固高温合金 超高周疲劳 疲劳特征 元素分布 弹性模量 

分 类 号：V250.3[一般工业技术—材料科学与工程]