TY - JOUR
T1 - Microstructure Evolution Associated with a Superior Low-Cycle Fatigue Resistance of the Fe-30Mn-4Si-2Al Alloy
AU - Nikulin, Ilya
AU - Sawaguchi, Takahiro
AU - Ogawa, Kazuyuki
AU - Tsuzaki, Kaneaki
N1 - Funding Information:
This work was financially supported by the New Energy and Industrial Technology Development Organization (NEDO) (06A25005d) and Grant-in-Aid for Scientific Research Fund (B) (No. 20360318) and (A) (No. 25249099) from the Japan Society for the Promotion of Science (JSPS). We would like to acknowledge the Materials Manufacturing and Engineering Station, NIMS, for the materials processing.
Publisher Copyright:
© 2015, The Minerals, Metals & Materials Society and ASM International.
PY - 2015/11/1
Y1 - 2015/11/1
N2 - The microstructure evolution responsible for the superior low-cycle fatigue (LCF) resistance (Nf > 8000 cycles at a total strain range of 2 pct) was studied in the Fe-30Mn-4Si-2Al alloy susceptible to strain-induced martensitic transformation. To investigate the microstructure effect on the LCF behaviors of the alloy, a series of interrupted fatigue tests at total strain range of 2 pct were carried out. A characteristic softening stage followed by the secondary hardening was observed during cyclic loading of the studied alloy. This softening is associated with the strain localization caused by persistent Lüders bands formation and the transformation of Lüders bands into strain-induced ε-martensite is found to have a key role in the delayed fatigue fracture of the alloy being studied. Therefore, the continuous transformation process involving Lüders bands and ε-martensite formation associated with intermediate stacking fault energy (SFE) (γSF of 14 mJ/m2) is necessary to prevent the rearrangement of dislocations into walls/channels and substructures inherent to high-SFE (γSF higher 20 mJ/m2) alloys capable to accelerated fatigue damage. However, sluggish martensite transformation kinetics is necessary to delay the formation of the ε-martensite associated with the development and propagation of fatigue crack in alloys with very low SFE.
AB - The microstructure evolution responsible for the superior low-cycle fatigue (LCF) resistance (Nf > 8000 cycles at a total strain range of 2 pct) was studied in the Fe-30Mn-4Si-2Al alloy susceptible to strain-induced martensitic transformation. To investigate the microstructure effect on the LCF behaviors of the alloy, a series of interrupted fatigue tests at total strain range of 2 pct were carried out. A characteristic softening stage followed by the secondary hardening was observed during cyclic loading of the studied alloy. This softening is associated with the strain localization caused by persistent Lüders bands formation and the transformation of Lüders bands into strain-induced ε-martensite is found to have a key role in the delayed fatigue fracture of the alloy being studied. Therefore, the continuous transformation process involving Lüders bands and ε-martensite formation associated with intermediate stacking fault energy (SFE) (γSF of 14 mJ/m2) is necessary to prevent the rearrangement of dislocations into walls/channels and substructures inherent to high-SFE (γSF higher 20 mJ/m2) alloys capable to accelerated fatigue damage. However, sluggish martensite transformation kinetics is necessary to delay the formation of the ε-martensite associated with the development and propagation of fatigue crack in alloys with very low SFE.
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U2 - 10.1007/s11661-015-3127-6
DO - 10.1007/s11661-015-3127-6
M3 - Article
AN - SCOPUS:84942987608
VL - 46
SP - 5103
EP - 5113
JO - Metallurgical and Materials Transactions A: Physical Metallurgy and Materials Science
JF - Metallurgical and Materials Transactions A: Physical Metallurgy and Materials Science
SN - 1073-5623
IS - 11
ER -