TY - JOUR
T1 - Effect of defects and hydrogen on the fatigue limit of Ni-based superalloy 718
AU - Kevinsanny,
AU - Okazaki, Saburo
AU - Takakuwa, Osamu
AU - Ogawa, Yuhei
AU - Okita, Koichi
AU - Funakoshi, Yusuke
AU - Yamabe, Junichiro
AU - Matsuoka, Saburo
AU - Matsunaga, Hisao
N1 - Publisher Copyright:
© 2019 The Authors. Published by Elsevier B.V.
PY - 2019
Y1 - 2019
N2 - Tension-compression fatigue tests were performed on two types of Ni-based superalloy 718 with different microstructures, to which small artificial defects of various shapes and sizes were introduced. Similar tests were also conducted on hydrogen-charged specimens with defects, with a solute hydrogen content ranging from 26.3 to 91.0 mass ppm. In the non-charged specimens in particular, the fatigue strength susceptibility to defects varied significantly according to the type of microstructural morphology, i.e., a smaller grain size made the alloy more vulnerable to defects. The fatigue limit as a small-crack threshold was successfully predicted using the √area parameter model. Depending on the size of defects, the fatigue limit was calculated in relation to three phases: (i) harmless-defect regime, (ii) small-crack regime and (iii) large-crack regime. Such a classification enabled comprehensive fatigue limit evaluation in a wide array of defects, taking into consideration (a) the defect size over a range of small crack and large crack and (b) the characteristics of the matrix represented by grain size and hardness. In addition, the effect of defects and hydrogen on fatigue strength will be comprehensively discussed, based on a series of experimental results. .
AB - Tension-compression fatigue tests were performed on two types of Ni-based superalloy 718 with different microstructures, to which small artificial defects of various shapes and sizes were introduced. Similar tests were also conducted on hydrogen-charged specimens with defects, with a solute hydrogen content ranging from 26.3 to 91.0 mass ppm. In the non-charged specimens in particular, the fatigue strength susceptibility to defects varied significantly according to the type of microstructural morphology, i.e., a smaller grain size made the alloy more vulnerable to defects. The fatigue limit as a small-crack threshold was successfully predicted using the √area parameter model. Depending on the size of defects, the fatigue limit was calculated in relation to three phases: (i) harmless-defect regime, (ii) small-crack regime and (iii) large-crack regime. Such a classification enabled comprehensive fatigue limit evaluation in a wide array of defects, taking into consideration (a) the defect size over a range of small crack and large crack and (b) the characteristics of the matrix represented by grain size and hardness. In addition, the effect of defects and hydrogen on fatigue strength will be comprehensively discussed, based on a series of experimental results. .
UR - http://www.scopus.com/inward/record.url?scp=85081544450&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=85081544450&partnerID=8YFLogxK
U2 - 10.1016/j.prostr.2019.12.034
DO - 10.1016/j.prostr.2019.12.034
M3 - Conference article
AN - SCOPUS:85081544450
VL - 19
SP - 312
EP - 319
JO - Procedia Structural Integrity
JF - Procedia Structural Integrity
SN - 2452-3216
T2 - Fatigue Design 2019 - 8th edition of the International Conference on Fatigue Design
Y2 - 20 November 2019 through 21 November 2019
ER -