Fatigue Crack Initiation in an Interstitial Free Steel
Fatigue Crack Initiation in an Interstitial Free Steel
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DOI：
10.2355/isijinternational.45.127
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发表时间：
2005-01
影响因子：
1.8
通讯作者：
N. Narasaiah;P. Chakraborti;R. Maiti;K. Ray
中科院分区：
文献类型：
--
作者：
N. Narasaiah;P. Chakraborti;R. Maiti;K. Ray
本文研究了无间隙原子（IF）钢的哑铃形平板试样在载荷比R=0，屈服应力幅在0.6 ~ 1.0之间变化时的小裂纹萌生。裂纹在铁素体-铁素体晶界（FFGB）和铁素体晶粒内（FGB）处形核，但前者是首选的形核位置。在相同的循环载荷条件下，FFGB裂纹的平均长度大于FGB裂纹的平均长度。晶粒内滑移带的形成，滑移带冲击晶界和弹塑性不相容协同影响裂纹萌生的事件在所研究的钢。此外，滑移带内的空洞形核被认为是一个新的现象与上述可能性，影响在所研究的钢中的裂纹形核。
The initiation of small cracks has been studied on dumble-shaped plate type specimens of an interstitial free (IF) steel at the load ratio of R=0 under varied cyclic stress amplitudes between 0.6 and 1.0 of yield stress. Nucleation of cracks were observed at ferrite-ferrite grain boundary (FFGB) as well as inside ferrite grain body (FGB), but the former location was found to be the preferred one. The average length of FFGB cracks is found larger than that of the FGB cracks for identical cyclic loading conditions. The formation of slip bands inside the grain body, slip band impingement at grain boundary and elastic-plastic incompatibility synergistically influence the event of crack initiation in the investigated steel. In addition, nucleation of voids inside slip bands was found to be a new phenomenon associated with the above possibilities to affect the nucleation of cracks in the investigated steel.