Citation: Choi, W.-K.; Ha, S.;
Kim, J.-C.; Park, J.-C.; Gong, A.;
Kim, T.-W. Oxidation Damage
Evolution in Low-Cycle Fatigue Life
of Niobium-Stabilized Austenitic
Stainless Steel. Materials 2022, 15,
4073. https://doi.org/10.3390/
ma15124073
Academic Editor: Andrea Di Schino
Received: 26 April 2022
Accepted: 5 June 2022
Published: 8 June 2022
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Article
Oxidation Damage Evolution in Low-Cycle Fatigue Life of
Niobium-Stabilized Austenitic Stainless Steel
Wan-Kyu Choi
1
, Sangyul Ha
2
, Jong-Cheon Kim
3
, Jong-Cheon Park
3
, Aokai Gong
4
and Tae-Won Kim
4,
*
1
Department of Automotive Engineering, Hanyang University, Seoul 04763, Korea; wanguu@hanyang.ac.kr
2
Department of Mechanical Engineering, Gachon University, Seongnam-si 13306, Korea;
dubuking@postech.ac.kr
3
Research & Development Headquarter, Hyundai Motor Company, Hwaseong-si 18280, Korea;
kjc8363@hyundai.com (J.-C.K.); skybell@hyundai.com (J.-C.P.)
4
Department of Mechanical Engineering, Hanyang University, Seoul 04763, Korea; gak971230@hotmail.com
* Correspondence: twkim@hanyang.ac.kr; Tel.: +82-02-2220-0421
Abstract:
Austenitic stainless steel is a vital material in various industries, with excellent heat and
corrosion resistance, and is widely used in high-temperature environments as a component for
internal combustion engines of transportation vehicles or power plant piping. These components
or structures are required to be durable against severe load conditions and oxidation damage in
high-temperature environments during their service life. In this regard, in particular, oxidation
damage and fatigue life are very important influencing factors, while existing studies have focused
on materials and fracture behavior. In order to ensure the fatigue life of austenitic stainless steel,
therefore, it is necessary to understand the characteristics of the fracture process with microstructural
change including oxidation damage according to the temperature condition. In this work, low-cycle
fatigue tests were performed at various temperatures to determine the oxidation damage together
with the fatigue life of austenitic stainless steel containing niobium. The characteristics of oxidation
damage were analyzed through microstructure observations including scanning electron microscope,
energy-dispersive X-ray spectroscopy, and the X-ray diffraction patterns. In addition, a unified low-
cycle fatigue life model coupled with the fracture mechanism-based lifetime and the Neu-Sehitoglu
model for considering the influence of damage by oxidation was proposed. After the low-cycle
fatigue tests at temperatures of 200–800
◦
C and strain amplitudes of 0.4% and 0.5%, the accuracy of
the proposed model was verified by comparing the test results with the predicted fatigue life, and the
validity by using the oxidation damage parameters for Mar-M247 was confirmed through sensitivity
analysis of the parameters applied in the oxidation damage model. As a result, the average thickness
of the oxide layer and the penetration length of the oxide intrusion were predicted with a mean error
range of 14.7% and 13%, respectively, and the low-cycle fatigue life was predicted with a
±
2 factor
accuracy at the measurement temperatures under all experimental conditions.
Keywords:
austenitic stainless steel; chromium carbide; oxidation damage; fatigue life; low-cycle fatigue
1. Introduction
Austenitic stainless steel is an important material in many industries, including auto-
motive engines, exhaust systems, aircraft gas turbines, home appliance motors, and power
plant turbine rotors, and can maintain durability with its heat and corrosion resistance,
especially in high-temperature environments of 600
◦
C or higher.
However, when austenitic stainless steel is used in the sensitization temperature range,
i.e., 400–850
◦
C, the affinity of chromium (Cr) and carbon (C) increases, and chromium
carbide (Cr
23
C
6
), a type of metal carbide (M
23
C
6
), is precipitated inside the material, and the
amount of chromium for suppressing the oxidation of the material decreases as carbon and
chromium bond with each other for the precipitation of Cr
23
C
6
[
1
–
3
]. During this process,
the thin chromium oxide layer (Cr
23
O
3
), which exists on the surface of the austenitic
Materials 2022, 15 , 4073. https://doi.org/10.3390/ma15124073 https://www.mdpi.com/journal/materials
