摘要
对G H4169合金中心孔板材进行冷挤压强化,研究其挤压前后825MPa/600℃/R=0.1疲劳寿命,分析挤压前后表面粗糙度变化和疲劳过程中的残余应力场演化,并细致观察两件挤压试样不同寿命(分别为25105周次和10719周次)断口以分析表面完整性对疲劳过程的作用.结果表明:相比原始试样,冷挤压强化后试样中值疲劳寿命估计量提高了1倍,挤压后较低的表面粗糙度和疲劳过程中稳定的残余应力场是疲劳寿命提高的主要原因.同时,挤压后疲劳寿命标准差增大.由断口定量分析可知,两件试样距疲劳源区0.1mm之后的扩展寿命相当,而萌生寿命(分别为18786周次和5915周次)却相差巨大.造成孔挤压后寿命分散性大的原因是0.1mm以内的裂纹萌生寿命差别.为提高孔结构疲劳性能稳定性,挤压时应注意近表层表面完整性的控制.
Cold expansion(CE)was applied on the centre-hole plate of GH4169 alloy.The fatigue lives,as received and after CE,were investigated at 825 MPa/600℃/R=0.1.Surface roughness before and after CE,residual stress profiles during fatigue cycles were studied.And the influence of surface integrity on fatigue process was analyzed by the careful fracture observation with two CE samples of different lives(25105 cycles and 10719 cycles).The results show that the median fatigue life estimation of specimens after CE doubles compared with as-received.The lower surface average roughness after CE and the stable residual stress profile during fatigue process are the main reasons for fatigue life promotion.However,the standard deviation of fatigue lives increases after CE.The fractographic quantitative analysis shows the propagation lives of two specimens beyond 0.1 mm from fatigue source are considered,but initiation lives(18786 cycles and 5915 cycles,respectively)are of great difference.As a contrast,the reason of the big dispersion about CE fatigue lives is the different initiation life within 0.1 mm from the source.Therefore,the attention should be paid to the surface integrity control of near surface during cold expansion to improve the stability of hole structure fatigue property.
作者
王欣
陈星
胡仁高
胡博
许春玲
汤智慧
古远兴
WANG Xin;CHEN Xing;HU Ren-gao;HU Bo;XU Chun-ling;TANG Zhi-hui;GU Yuan-xing(Surface Engineering Institution,AECC Beijing Institute of Aeronautical Materials,Beijing 100095,China;Aviation Key Laboratory of Advanced Corrosion and Protection on Aviation Materials,AECC Beijing Institute of Aeronautical Materials,Beijing 100095,China;Testing Research Center,AECC Beijing Institute of Aeronautical Materials,Beijing 100095,China;AECC Sichuan Gas Turbine Establishment,Chengdu 610500,China)
出处
《材料工程》
EI
CAS
CSCD
北大核心
2020年第6期156-162,共7页
Journal of Materials Engineering
关键词
冷挤压
孔结构
疲劳
断口定量分析
cold expansion
hole structure
fatigue
fractographic quantitative analysis
