Effect of hold time on high temperature creep-fatigue behavior of Fe-25Ni-20Cr (wt.%) austenitic stainless steel (Alloy 709)

MATERIALS SCIENCE AND ENGINEERING A-STRUCTURAL MATERIALS PROPERTIES MICROSTRUCTURE AND PROCESSING

卷:771

Article

Alsmadi, Zeinab Y.¹  Alomari, Abdullah^1,2  Kumar, N.³  Murty, K. L.¹ 

[1] North Carolina State Univ, Dept Nucl Engn, Raleigh, NC 27695 USA

[2] King Abdullaziz City Sci & Technol, Nucl Sci Res Inst, Riyadh 114426086, Saudi Arabia

[3] Univ Alabama, Met & Mat Engn, Tuscaloosa, AL 35487 USA

关键词: Advanced austenitic stainless steel;    Low-cycle fatigue;    Creep-fatigue;    Hold time;    Intergranular;    Transgranular;   

DOI  :  10.1016/j.msea.2019.138591

来源: Elsevier

【 摘 要 】

To understand high temperature creep-fatigue interaction of the Alloy 709, strain-controlled low-cycle fatigue (LCF) tests were performed at strain ranges varying from 0.3% to 1.2% with fully reversible cycle of triangular waveform at 750 degrees C. In addition, different hold times of 60, 600, 1800 and 3600s were introduced at the maximum tensile strain to investigate the effect of creep damage on the fatigue-life at strain range of 1% at 750 degrees C. The creep-fatigue life and the number of cycles to macro-crack initiation and failure are found to decrease with increasing hold time indicating higher crack initiation and growth rates. Creep-fatigue life is evaluated by a linear summation of fractions of cyclic and creep damages according to ASME code. The fractographs of the samples deformed at 1% strain range indicated that fatigue might have been the dominant mode of deformation whereas, for the samples deformed at the same strain range with different hold times, both fatigue and creep have contributed to the overall deformation and fracture of the alloy.

【 授权许可】

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