Low Cycle Fatigue, Creep-Fatigue and Relaxation-Fatigue Tests on P91  

作　　者：Carlo Cristalli Pietro Agostini Davide Bemardi Nicola Bettocchi Luigi Masotti Sandro Storai 

机构地区：[1]ENEA CR Brasimone, Camugnano (BO) 40032, Italy

出　　处：《Journal of Physical Science and Application》2017年第2期18-26,共9页物理科学与应用（英文版）

摘　　要：Creep-fatigue is a damage mechanism where cyclic deformation damage （fatigue） is enhanced by creep damage and vice versa. Factors affecting the creep-fatigue damage are stress level （or, equivalently, strain range）, temperature, hold time period, material softening/hardening and number of cycles. Moreover, environmental effects can accelerate the creep-fatigue interaction （oxidation, hot corrosion, irradiation, etc.）. The activity described in this paper was planned to perform tests on 9Cr-lMo ferritic/martensitic steel （P91） combining fatigue cycles and constant tensile and compressive holding periods. A preliminary basic fatigue characterization campaign in the LCF （low cycle fatigue） regime was carried out by performing a series of strain controlled tests, each at the same temperature （550 ℃）, using two different values for the total strain range （1% and 0.6%） and the same total strain rate （2×10^-3 s^-1）. The tests were carried out with a strain ratio of-l, i.e., in fully reversed cyclic conditions. In this paper we illustrate the results obtained by testing in air P91 （9Cr-lMo） ferritic/martensitic steel, introducing different dwell periods （either in strain or load control） and obsetwing how these affect the fatigue life of the specimens. The final aim of the activity is to investigate how much detrimental is the effect of the holding periods on the fatigue life in order to validate the creep-fatigue interaction diagram presently adopted in RCC-MRx code for the P91 steel.

关 键 词：P91 CREEP-FATIGUE fatigue damage creep damage interaction diagram RCC-MRx softening. 

分 类 号：O4[理学—物理]