摘要
研究了定向凝固合金DZ125U型平板缺口试样在850℃下的缺口疲劳行为,进行了理论应力集中因子分别为1.91,3.01和4.35下的疲劳试验,原位观察了疲劳裂纹的萌生位置和扩展方向,并进行了疲劳寿命分析和裂纹萌生与扩展分析.结果表明:理论应力集中因子关联缺口疲劳寿命.随着名义应力的增加,缺口疲劳寿命对理论应力集中因子更敏感,而在低应力范围内,正好相反.通过原位观测技术,试验中还发现缺口疲劳裂纹的萌生和扩展并没有在最大轴向应力的缺口根部,而是缺口附近最大主应力位置.
Notched fatigue behavior of directional solidified superalloy DZ125 at 850 ℃ was investigated.Different U type notched specimens with three stress concentration factors including 1.91,3.01,and 4.35 were tested.Crack initiation and propagation were observed in situ.The fatigue life and crack initiation and propagation were analyzed.The results indicate that stress concentration factor is an important parameter infect the life to fatigne failures,while converse results obtained at low stress range.With the increase of norminal stress,the notch fatigue life became more sensitive to stress concentration factor.Through in situ observation,it＇s found that the locations of the crack initiation and propagation were not at the root of the notch,but at the location with maximum principal stress.
出处
《航空动力学报》
EI
CAS
CSCD
北大核心
2013年第7期1613-1617,共5页
Journal of Aerospace Power
关键词
疲劳
缺口
应力集中因子
裂纹
高温
定向凝固合金
fatigue
notch
stress concentration factor
crack
high temperature
directional solidified superalloy
