(1. 中國(guó)科學(xué)院 金屬研究所，沈陽(yáng) 110016；
2. 鋼鐵研究總院 高溫材料研究所，北京 100081)
摘 要: 對(duì)GH4698合金在室溫、650及750 ℃的裂紋擴(kuò)展行為進(jìn)行研究，討論溫度對(duì)裂紋擴(kuò)展壽命與速率的影響，觀察不同溫度下的裂紋擴(kuò)展斷口。采用背散射電子衍射(EBSD)技術(shù)對(duì)合金裂紋擴(kuò)展的晶體學(xué)機(jī)制進(jìn)行分析。結(jié)果表明，隨著溫度的升高，合金的裂紋擴(kuò)展壽命降低，裂紋擴(kuò)展速率增加，斷裂模式由室溫下穿晶斷裂為主轉(zhuǎn)變?yōu)楦邷叵碌难鼐嗔褳橹鳎涣鸭y附近應(yīng)變程度較大，且小角度晶界密度較高。
關(guān)鍵字: 鎳基高溫合金；疲勞裂紋擴(kuò)展；疲勞機(jī)制
（1. Institute of Metal Research, Chinese Academy of Sciences, Shenyang 110016, China;
2. High Temperature Materials Research Institute, Central Iron and Steel Research Institute, Beijing 100081, China）
Abstract:The crack propagation behavior of GH4698 alloy was studied respectively at room temperature, 650 and 750 ℃. The effects of temperature on the crack propagation rate were discussed, the fractures under different temperatures were observed and the electron back scattering diffraction (EBSD) technique was applied to investigate the mechanism of crack propagation. The results show that with the increase of temperature, the fatigue life of the alloy reduces and crack propagation rate increases, and the main propagation mode of cracks changes from transgranular to intergranular. The grains near cracks have relative high deformation degree and high density, small angle grain boundaries.
Key words: Ni-based superalloy; fatigue crack propagation; fatigue mechanism
