TY - JOUR
T1 - Microstructural damage mechanics-based model for creep fracture of 9%Cr steel under prior fatigue loading
AU - Zhang, Wei
AU - Wang, Xiaowei
AU - Chen, Haofeng
AU - Zhang, Tianyu
AU - Gong, Jianming
PY - 2019/10/1
Y1 - 2019/10/1
N2 - Predicting the remnant creep fracture life precisely is crucial for ensuring safety of high temperature components. This study presents a microstructural damage mechanics-based model for creep fracture of 9%Cr steel under prior fatigue loading. Microstructure observation reveals that the decrease of dislocation density and the growth of martensite lath width occurred during prior fatigue process contribute to the degradation of creep strength. Particularly, coarsening of martensite lath width plays the dominated role. To take into account the effect of the prior fatigue loading, kinematic damage equations that represent the evolution of dislocation density and martensite lath are proposed in the developed model. With the proposed model, creep fracture life and creep failure strain at various lifetime factions, strain amplitudes and hold times of prior fatigue loading can be satisfactorily predicted, which manifests that the proposed model is robust in capturing the effects of various prior fatigue loadings. The proposed model is also shown to be able to accurately predict prolonged creep deformation of other similar steel after different prior fatigue loadings.
AB - Predicting the remnant creep fracture life precisely is crucial for ensuring safety of high temperature components. This study presents a microstructural damage mechanics-based model for creep fracture of 9%Cr steel under prior fatigue loading. Microstructure observation reveals that the decrease of dislocation density and the growth of martensite lath width occurred during prior fatigue process contribute to the degradation of creep strength. Particularly, coarsening of martensite lath width plays the dominated role. To take into account the effect of the prior fatigue loading, kinematic damage equations that represent the evolution of dislocation density and martensite lath are proposed in the developed model. With the proposed model, creep fracture life and creep failure strain at various lifetime factions, strain amplitudes and hold times of prior fatigue loading can be satisfactorily predicted, which manifests that the proposed model is robust in capturing the effects of various prior fatigue loadings. The proposed model is also shown to be able to accurately predict prolonged creep deformation of other similar steel after different prior fatigue loadings.
KW - prior fatigue loading
KW - microstructure damage model
KW - creep fracture
KW - lath width
KW - dislocation density
UR - https://www.sciencedirect.com/journal/theoretical-and-applied-fracture-mechanics
U2 - 10.1016/j.tafmec.2019.102269
DO - 10.1016/j.tafmec.2019.102269
M3 - Article
VL - 103
JO - Theoretical and Applied Fracture Mechanics
JF - Theoretical and Applied Fracture Mechanics
SN - 0167-8442
M1 - 102269
ER -