DD98M镍基单晶高温合金900℃高周疲劳行为.pdf

48 2 2012 2 170—175 ACTA METALLURGICA SINICA Feb. 2012 –175 DD98M 900 ? 1) 2) 1) 1) 1) 1) 1) , 110016 2) , 110819 Re DD98M 900 . : , , 900 574 360 MPa; (SEM) , , , , ; (TEM) , , γ?, γ?. , , , , A 0412 ?1961(2012)02 ? 0170 ? 06 HIGH CYCLE FATIGUE BEHAVIOR OF ANICKEL–BASED SINGLE CRYSTAL SUPERALLOY DD98M AT 900 HAN Guoming 1), ZHANG Zhenxing 2),LIJinguo 1),JINTao 1), SUN Xiaofeng 1), HU Zhuangqi 1) 1) Institute of Metal Research, Chinese Academy of Sciences, Shenyang 110016 2) School of Materials and Metallurgy, Northeastern University, Shenyang 110819 Correspondent: SUN Xiaofeng, professor, Tel: (024)23971713 , E-mail: ******@imr. Supported by National Basic Research Program of China (No. 210CB631206 ) Manuscript received 2011–07–08, in revised form 2011–11–14 ABSTRACT High cycle fatigue (HCF) behavior of the second generation single crystal nickel–based superalloy DD98M without Re addition at 900 was investigated. The results indicate that HCF lifetime is reduced with increase of cyclic stress am plitude. Compared to smooth specimens, the fatigue lifetime and strength of notched specimens are decreased markedly. The fatigue strengths for smooth and notched specimens are 574 MPa and 360 MPa, respectively. Fracture observation by SEM shows that there exist many sites of crack initiation for n otched specimens due to stress concentration of the notch,