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Article

Comparison of Novel Low-Carbon Martensitic Steel to Maraging Steel in Low-Cycle Fatigue Behavior

by
Bo Lv
1,
Shule Xia
2,3,
Fucheng Zhang
3,
Guang Yang
3 and
Xiaoyan Long
3,4,*
1
School of Environmental and Chemical Engineering, Yanshan University, Qinhuangdao 066004, China
2
CITIC Dicastal Co., Ltd., Qinhuangdao 066004, China
3
State Key Laboratory of Metastable Materials Science and Technology, Yanshan University, Qinhuangdao 066004, China
4
Key Laboratory of Mechanical Reliability for Heavy Equipments and Large Structures of Hebei Province, Yanshan University, Qinhuangdao 066004, China
*
Author to whom correspondence should be addressed.
Coatings 2022, 12(6), 818; https://doi.org/10.3390/coatings12060818
Submission received: 23 May 2022 / Revised: 9 June 2022 / Accepted: 10 June 2022 / Published: 10 June 2022
(This article belongs to the Special Issue Microstructure, Fatigue and Wear Properties of Steels)
Browse Figures
Versions Notes

Abstract

:
The study systematically compares the low-cycle fatigue (LCF) behaviors of novel martensitic steel (22MnSi2CrMoNi) and maraging steel (00Ni18Co9Mo4Ti). Results show that the two types of tested steel have a similar cyclic deformation behavior. The cyclic softening resistance of 22MnSi2CrMoNi steel is slightly inferior to that of 00Ni18Co9Mo4Ti steel at a low total strain amplitude. However, the gap gradually disappears with the increase of the total strain amplitude. At the same plastic strain amplitude, the LCF lifetime of 22MnSi2CrMoNi steel is higher than that of 00Ni18Co9Mo4Ti steel. The retained austenite film between martensite lath and the existence of precipitated phase in matrix can effectively improve the fatigue lifetime of the two types of tested steel.

1. Introduction

Ultra-high-strength 18Ni series maraging steel not only has excellent toughness, weldability, and excellent processing performance but also has a relatively simple heat treatment. It is widely used in military and heavy industry [1,2,3]. A series of new steel with comprehensive mechanical properties close to that of maraging steel has been developed and studied [4,5,6,7]. However, studies have mainly focused on the mechanical properties and microstructure of tested steel but rarely on their fatigue properties. High-strength components are often subjected to various cyclic loads during their service [8,9,10]. When the local stress exceeds the yield strength, plastic strain gradually occurs in this area and a fatigue crack can be initiated under the continuous action of cyclic load. Low-cycle fatigue (LCF) damage is one of the most common failure modes encountered by engineering components during actual service. Therefore, LCF is usually considered in material design to prevent failure behavior under cyclic loading [11,12].
LCF investigation of martensitic steel includes microstructure evolution [13,14], LCF behavior [15,16] and damage mechanics [17,18]. Cyclic softening behavior can be observed under cyclic loading, which is related to dislocation and martensitic lath [13]. 22MnSi2CrMoNi low-carbon martensitic steel is a new type of advanced high-strength steel. 22MnSi2CrMoNi has higher tensile strength and elongation than other high-strength steels [6]. The high Si content in steel suppresses the conversion of ε-carbides to Fe3C [19]. Film retain austenite between lath martensites is conducive to crack passivation, branching, or diversion [20,21], resulting in excellent mechanical properties, fracture toughness, fatigue crack initiation, and propagation resistance of 22MnSi2CrMoNi steel. Its comprehensive mechanical properties are equivalent to those of high-alloyed 00Ni18Co9Mo4Ti steel [6], but its alloy cost is lower than that of maraging steel. The LCF properties of 22MnSi2CrMoNi steel have yet to be investigated. Fatigue damage model has been well applied in alloy and steel [22,23]. Zhang et al. [24] used the hysteresis energy method to evaluate LCF lifetime. A new kind of martensitic steel with low carbon content is obtained by improving the heat-treatment process. The hysteresis energy method is used to evaluate the fatigue performance of martensitic steel. The LCF of low-carbon martensitic steel is evaluated by comparing the LCF of martensitic steel and martensitic aging steel. Previous studies mainly used methods based on stress or strain to evaluate the LCF [25]. Few studies have used hysteresis energy method to evaluate the fatigue properties of martensitic steels [26].
The LCF of 22MnSi2CrMoNi low-carbon martensitic steel and 00Ni18Co9Mo4Ti steel are examined in terms of four aspects: cyclic deformation behavior, LCF life prediction, microstructure evolution, and fracture analysis. The microscopic mechanism of martensitic steel cyclic deformation is explored.

2. Materials and Experimental Procedures

The tested material used in this study was 22MnSi2CrMoNi steel and the comparative material was 00Ni18Co9Mo4Ti steel. The chemical composition of the tested steel is shown in Table 1. 22MnSi2CrMoNi steel was austenitized at 900 °C for 1h and then water quenched. The tested steel was tempered at 320 °C for 1 h. 00Ni18Co9Mo4Ti steel was heat treated at 860 °C for 0.5 h, quenched with water and aged at 480 °C for 4 h.
The standard tensile tested was used on a servo-hydraulic mechanical testing system. Tensile tests were carried out on an MTS material testing machine (MTS, Eden Prairie, MN, USA) with a tensile strain rate of 0.3 mm/min. Three tensile specimens with a gauge length of 25 mm and a gauge diameter of 5 mm were prepared for each treated steel, and the dimensional tolerance was 0.02 mm. U-notched impact samples with dimensions of 10 mm × 10 mm × 55 mm were used on an instrumental impact tester. The specimen size is 10 mm × 10 mm × 55 mm. The impact toughness of the tested steel was obtained with 3 samples in each group. Three specimens were tested under each condition. The LCF specimen was a round rod with a size of ϕ 5 mm × 10 mm. The specimen size tolerance was 0.02 mm and the surface roughness was 0.2 μm. Three fatigue specimens were tested in each group. LCF testing was performed using the MTS servo hydraulic test system and tests were controlled using total strain amplitudes of 0.52%, 0.6%, 0.7%, 0.8%, and 1.0%. A triangle waveform (R = −1) with a constant strain rate of 6 × 10−3 s−1 was used. The fatigue test specimens used in the present work are depicted in Figure 1. All the samples were tested at constant total strain amplitude. The standard for evaluating the fatigue cycle failure was the fracture of the sample or the reduction of 25% in peak tensile load compared with the maximum peak value.
The morphological characteristics of the LCF fracture were observed using an SU5000 scanning electron microscope (SEM, Hitachi, Tokyo, Japan) at 15 kV. The microstructure of the specimen after cyclic deformation was examined under a transmission electron microscope (TEM, Thermo Fisher, Waltham, MA, USA). TEM microstructure was observed by Hitachi H-800 transmission electron microscope at 200 kV. TEM samples were thinned to perforation on a TenuPol-5 twin-jet unit, and voltage is 28 V. The phase content and the dislocation density of the tested steel were analyzed using X-ray diffractometer. The type is a D/max-2500/PC, and radiation was Cu-Kα.

3. Results and Discussion

3.1. Microstructure and Mechanical Properties

Figure 2 exhibits the TEM micrographs of 22MnSi2CrMoNi and 00Ni18Co9Mo4Ti steel. The TEM microstructure of 22MnSi2CrMoNi steel is mainly lath martensite (Figure 2a). A film retained austenite between the lath martensites and a small amount of ε-carbide diffusely distributed on the lath martensite are observed. The TEM microstructure of 00Ni18Co9Mo4Ti steel is shown in Figure 2b. A high dislocation density is detected within the lath martensite. A large number of nano-sized spherical, rod-like, or needle-like precipitates Ni3(Mo, Ti) are uniformly dispersed in the lath martensite, and this is almost universally accepted [2,3,5,6].
The engineering stress–strain curves for the two tested steels are illustrated in Figure 3. The corresponding mechanical properties are shown in Table 2. The hardness, tensile strength, and impact toughness of 22MnSi2CrMoNi steel are higher than those of 00Ni18Co9Mo4Ti steel. Conversely, the yield strength of 22MnSi2CrMoNi steel is slightly lower than that of 00Ni18Co9Mo4Ti steel. 00Ni18Co9Mo4Ti steel has higher resistance to dislocation slip, resulting in higher yield strength.
In terms of microstructure, the retained austenite film between martensite lath in 22MnSi2CrMoNi can prevent crack propagation and improve fatigue life. The higher dislocation density and nanoscale precipitates in 00Ni18Co9Mo4Ti steel can improve its fatigue life. In terms of mechanical properties, the higher tensile strength of 22MnSi2CrMoNi steel is beneficial to improve its fatigue life. The higher yield strength of 00Ni18Co9Mo4Ti steel is beneficial to improve its fatigue life.

3.2. Cyclic Deformation Behavior

The cyclic hardening/softening curves of 22MnSi2CrMoNi and 00Ni18Co9Mo4Ti steel are showed in Figure 4. 22MnSi2CrMoNi steel shows a significant continuous cyclic softening phenomenon at strain amplitudes except at strain amplitude of 0.52% (Figure 4a). The curve is analyzed in three stages. The cyclic softening rate (SR) and the corresponding damage mechanism vary at each stage. The first stage involves the rapid cyclic softening. The second stage is the saturated stage of cyclic stress stability. In the first two stages of the steel test the microstructures evolve. As cyclic deformation progresses, the original dislocation substructure gradually shifts to a low-energy cell substructure [27,28]. The third stage is the rapid softening failure stage in which crack initiation and propagation result in the failure of the tested steel.
However, at the 0.52% total strain amplitude, the tested steel exhibits continuous cyclic softening after a brief and slight cyclic hardening occurs. This phenomenon is the same as the change in the SR at other strain amplitudes. 00Ni18Co9Mo4Ti steel shows a stable cyclic softening after a brief and slight cyclic hardening when the strain amplitude is less than 0.6% (Figure 4b). Once the surface of the specimen cracks, a rapid softening failure occurs. When the total strain amplitude is higher than 0.6%, 00Ni18Co9Mo4Ti steel shows an obvious continuous cyclic softening phenomenon. 00Ni18Co9Mo4Ti steel has the same performance as 22MnSi2CrMoNi steel when the total strain amplitude is higher than 0.52%. Therefore, the cyclic deformation behavior of the two tested steels is similar. The LCF life of the two tested steels can be observed from Figure 4. The LCF lifetime of the 22MnSi2CrMoNi steel is longer than 00Ni18Co9Mo4Ti steel at lower strain amplitude. The LCF lifetime of the 22MnSi2CrMoNi steel is shorter than 00Ni18Co9Mo4Ti steel at higher strain amplitude.
Neither 22MnSi2CrMoNi steel nor 00Ni18Co9Mo4Ti steel exhibits a remarkable cyclic hardening behavior, but their cyclic softening is substantial, and the cyclic SR increases as strain amplitude increases. The cyclic SR is calculated using the following formula [13]:
SR = σ 1 − σ Hf / 2 σ 1
where σ 1 is the stress amplitude in the first cycle, σ H f / 2 is the stress amplitude in the half-life cycle. The calculated cyclic SRs of 22MnSi2CrMoNi and 00Ni18Co9Mo4Ti steel are shown in Figure 5. In particular, their cyclic SR increases as their strain range increases. When the strain amplitude is lower than 0.6%, 00Ni18Co9Mo4Ti steel does not appear cyclic softening. However, the cyclic SR increases linearly with strain range when the total strain amplitude is between 0.6% and 1.0%. The cyclic softening resistance of 22MnSi2CrMoNi steel at a low total strain amplitude is slightly inferior to that of 00Ni18Co9Mo4Ti steel, but this difference gradually disappears as the total strain amplitude increases. This is because the proportion of plastic strain component increases with the increase of strain amplitude.
The cyclic softening rate increases with the increase of strain amplitude. The cyclic softening behavior is related to the microstructure. As the number of cycles increases, dislocation slip results in the accumulation of a large number of dislocations between the slip plane and lath martensite. Dislocation entanglement forms dislocation cells leading to softening of circulation.
The results of stress amplitude curve and cyclic softening rate show that 22MnSi2CrMoNi steel has lower fatigue property than 00Ni18Co9Mo4Ti steel at lower strain amplitude. Therefore, at lower strain amplitude, the fatigue life of 22MnSi2CrMoNi steel is lower than that of 00Ni18Co9Mo4Ti steel. However, the fatigue property of 22MnSi2CrMoNi steel is better than 00Ni18Co9Mo4Ti steel at higher strain amplitude. Therefore, the fatigue life of 22MnSi2CrMoNi steel is higher than 00Ni18Co9Mo4Ti steel.

3.3. LCF Lifetime

The curves of plastic strain amplitude, elastic strain amplitude, and total strain amplitude of 22MnSi2CrMoNi steel and 00Ni18Co9Mo4Ti steel during half-life are shown in Figure 6. Figure 6a illustrates that the LCF lifetime of 22MnSi2CrMoNi steel gradually decreases as the strain range increases. The plastic strain amplitude and the elastic strain amplitude intersect at one point at 1000 cycles. The corresponding cycle is the transition fatigue lifetime of 22MnSi2CrMoNi steel [29]. The size of transition fatigue life is mainly controlled by the strength and ductility of a given material [30]. In Figure 6a,b, the transition fatigue of 22MnSi2CrMoNi and 00Ni18Co9Mo4Ti steel are 1000 and 1183 cycles, respectively. The transition fatigue lifetime of 22MnSi2CrMoNi steel is lower than that of 00Ni18Co9Mo4Ti steel, but they belong to the same level. It is further shown that the ability of 22MnSi2CrMoNi steel and 00Ni18Co9Mo4Ti steel to accommodate cyclic plastic deformation is comparable.
The relationship between cyclic stress and fatigue lifetime can be expressed by the Basquin formula [31]:
Δ σ 2   = σ f ′ ( 2 N f ) b
where σ f ′ and b are the fatigue strength coefficient and the fatigue strength index, respectively; Nf is the fatigue lifetime; ∆σ is a cyclic stress. The fatigue strength coefficient is thought to be related to the true fracture strength of a tested steel. The relationship between plastic strain amplitude and fatigue life can be expressed by the Coffin–Manson [32,33] Equation:
Δ ε p 2 = ε f ′ ( 2 N f ) c
where ε f ′ represents the fatigue ductility coefficient, c represents fatigue ductility index; ∆εp is the cyclic plastic strain.
The fitting parameters obtained by Equations (2) and (3) are shown in Table 3. Ellyin et al. [34] proposed a method to calculate the hysteretic energy of each cycle based on the hysteretic energy model. The hysteretic energy model reflecting the strength and plasticity of materials is used instead of Coffin–Manson’s law and Basquin’s law, commonly used in martensitic steel. The method of hysteretic energy model has been well used in the life prediction of many materials. The relationship between hysteretic energy and fatigue lifetime is expressed by the hysteretic energy model [35]:
W s = W 0 · N f − 1 / β
where W s is the hysteretic energy of the half-life. The intrinsic fatigue toughness W 0 represents the fatigue damage capacity of a specific material. A high W 0 corresponds to high fatigue damage tolerance. The damage transition exponent β represents the ability of mechanical work to be transformed into an effective damage to materials. The increase of β value means that with the increase of external mechanical work, the effective damage transition is low, and the fatigue lifetime decreases slowly. W0 and β are beneficial to the improvement of fatigue life.
It can be seen that σ f ′ and ε f ′ of 22MnSi2CrMoNi steel is lower than that of 00Ni18Co9Mo4Ti steel. This means that 00Ni18Co9Mo4Ti steel has higher true fracture strength and true fracture strain than 22MnSi2CrMoNi steel. Therefore, 00Ni18Co9Mo4Ti steel has better LCF properties when Equations (2) and (3) are used to predict the fatigue life of the two tested steels. W 0 of 22MnSi2CrMoNi steel is lower than that of 00Ni18Co9Mo4Ti steel. β of the former is higher than that of the latter. The hysteresis loop is used to separate the strain into plastic and elastic components. It can comprehensively analyze its LCF properties. From the fatigue damage hysteretic energy model, it can be seen that both steels have excellent LCF fatigue properties.
The plastic strain amplitude curves in Figure 7a are fitted according to Formula (3). In Figure 7a, the LCF lifetime of 22MnSi2CrMoNi steel is higher than that of 00Ni18Co9Mo4Ti steel at the same plastic strain amplitude. LCF lifetime mainly depends on the plastic strain amplitude of materials [36]. Therefore, it can be concluded that 22MnSi2CrMoNi steel has better LCF properties than 00Ni18Co9Mo4Ti steel from the influence of plastic strain amplitude on fatigue lifetime. In Figure 7b, the fatigue lifetime of 22MnSi2CrMoNi and 00Ni18Co9Mo4Ti steel is similar at the same total strain amplitude. The fatigue lifetime of 22MnSi2CrMoNi steel is slightly higher than that of 00Ni18Co9Mo4Ti steel at a high total strain amplitude. The fatigue lifetime is mainly determined by the yield strength of a material at a low total strain amplitude. A high yield strength indicates that the elastic strain accounts for a large proportion at a given total strain amplitude.
The amplitude curve of cyclic stress in Figure 7c is fitted according to Formula (2). In Figure 7c, the fatigue lifetime of 00Ni18Co9Mo4Ti steel is significantly longer than that of 22MnSi2CrMoNi steel at high stress amplitudes. However, the difference between 22MnSi2CrMoNi steel and 00Ni18Co9Mo4Ti steel gradually decreases as the stress amplitude decreases. The softening resistance advantage of 00Ni18Co9Mo4Ti steel gradually disappears. The fatigue lifetime of 22MnSi2CrMoNi and 00Ni18Co9Mo4Ti steel is similar. This observation is mainly due to the higher yield strength of 00Ni18Co9Mo4Ti steel. In general, a high yield strength corresponds to a resistance to dislocation movement [37,38,39]. Therefore, the reduction of the density of slip dislocations decreases the number of irreversible slip dislocations thereby suppressing fatigue damage. Figure 7d shows the variation curve of hysteretic energy with the number of reversals to failure. The fatigue lifetime of 00Ni18Co9Mo4Ti steel is slightly higher than that of 22MnSi2CrMoNi steel under the same hysteretic energy.

3.4. Microstructure Evolution

From the perspective of dislocation stress, the peak stress (σp) during cyclic deformation can be decomposed into effective stress components (σ*) and internal stress components (σi) acting on dislocations. σp can be expressed as follows [40]:
σ p = σ * + σ i
where σ* is mainly the short-range stress formed by the pinning of dislocations by interstitial air mass such as carbon and oxygen; σi is the long-range interaction of dislocations, other dislocations, and subgrain boundaries. The Handifield–Dickson method can be used to calculate σi and σ* of the tested steel during cyclic deformation [40]. The evolution of σi and σ* of 22MnSi2CrMoNi and 00Ni18Co9Mo4Ti steel is shown in Figure 8. At the 0.52% total strain amplitude of 22MnSi2CrMoNi steel, σi and σ* remain stable as the number of cycle times increases. When the total strain amplitude is higher than 0.6%, σ* and σi of 22MnSi2CrMoNi steel decrease with the number of cycle times increasing. At the 0.52% total strain amplitude of 00Ni18Co9Mo4Ti steel, σi and σ* are in a stable state when the cycle times are less than 104. Conversely, both parameters decrease when the cycle times are higher than 104. When the total strain amplitude is higher than 0.6%, σi and σ* of the tested steel decrease with the number of cycle times increasing.
The evolution of internal stress and effective stress of 22MnSi2CrMoNi and 00Ni18Co9Mo4Ti steel can be explained by the following sentences. 22MnSi2CrMoNi steel has a high dislocation density of up to 2.91 × 1015 m−2. The dislocation density inside the lath martensite continuously proliferates resulting in many mobile dislocations. The interaction between dislocations results in the formation of many dislocation tangles and immovable dislocations because of high dislocation density of 22MnSi2CrMoNi steel. The annihilation of dislocations occurs, that is, the dislocations meet and cancel each other out. The short-range stress σ* formed by the pinning action of the interstitial air mass on the dislocations also remains stable. When the total strain amplitude is greater than 0.6% and the number of cycles increases, the energy provided by plastic deformation causes the lath martensite to recover and the dislocation density to gradually decrease. Therefore, the value of σi and σ* will decrease, and material exhibits cyclic softening. The yield strength of 00Ni18Co9Mo4Ti steel is higher than that of 22MnSi2CrMoNi steel. Therefore, the resistance of 00Ni18Co9Mo4Ti steel to plastic deformation is enhanced, and the cyclic softening phenomenon is delayed.
Figure 9 shows the dislocation morphology of 22MnSi2CrMoNi and 00Ni18Co9Mo4Ti steel safter the failure of cyclic deformation at 1.0% total strain amplitude. They are taken from the fracture surface. After the fatigue failure of 22MnSi2CrMoNi and 00Ni18Co9Mo4Ti steel at a total strain amplitude of 1.0%, the dislocation cells with many dislocations are formed in the lath martensite region. The formation and development of dislocation cells are a process in which dislocations in motion are partially eliminated and the free-slip distance increases. Dislocation cells are a manifestation of a low-energy state. Their appearance is conducive to the increase in plastic deformation capacity.

3.5. Fracture Analysis

The fracture morphology of specimens mainly consists of three parts: a fatigue crack initiation region, a crack propagation stability region, and an instability transient region. Figure 10 shows the SEM morphology of the fatigue crack initiation region of the two types of tested steel. Moreover, the fatigue cracks of the two tested steels originate on the surface of the sample. Fatigue cracks usually initiate at the stress concentration on metal surfaces. The fatigue fracture surface of 22MnSi2CrMoNi steel shows a distinct river pattern. The main crack is obvious at total strain amplitude of 0.52%. The fracture morphology of 00Ni18Co9Mo4Ti steel does not show a river pattern. The primary crack is smaller, and the secondary crack is less at total strain amplitude of 0.52%.
The microscopic morphology of the fatigue crack propagation stability region of the two types of tested steel is shown in Figure 11. Visible fatigue striations are important features of the region with stable fatigue crack propagation. The fatigue striations of 22MnSi2CrMoNi steel at total strain amplitude of 0.52% is short and discontinuous (Figure 11a), and the number of secondary cracks is large. As the total strain amplitude increases to 1.0% (Figure 11e), the fatigue striation spacing of the specimen increases significantly, indicating that the maximum fatigue crack propagation rate of the specimen is observed at this time. At different total strain amplitudes, the variation in fatigue striation of 00Ni18Co9Mo4Ti steel is the same as that of 22MnSi2CrMoNi steel (Figure 11b,d,f). Neumann [41] used a coarse slip model and observed that fatigue cracks form during propagation; that is, under cyclic tension and compression stress, the sliding on the alternating sliding surface repeatedly opens and closes, causing the crack tip to sharpen, passivate, and propagate. In 22MnSi2CrMoNi low-carbon martensitic steel, the film retained austenite between laths can split, divert, or passivate cracks and consume energy for crack propagation. Therefore, the resistance to fatigue cracks propagation increases [42,43]. In 00Ni18Co9Mo4Ti steel, a certain film austenite forms between lath martensites. Their effect occurs by inducing plasticity through phase transformation, splitting, turning, or passivating cracks. As a result, the propagation of fatigue cracks is hindered. Therefore, the resistance of both types of tested steel to fatigue crack propagation is enhanced.
The comparison of the cyclic deformation behavior, LCF lifetime, microstructure evolution, and fatigue crack initiation and propagation behavior of 22MnSi2CrMoNi and 00Ni18Co9Mo4Ti steel shows that 22MnSi2CrMoNi steel has excellent LCF properties. It belongs to the same level as the LCF properties of 00Ni18Co9Mo4Ti steel. 22MnSi2CrMoNi steel has the advantages of low alloy element content, low cost, and simple heat-treatment process. Hence, 22MnSi2CrMoNi steel has application advantages over 00Ni18Co9Mo4Ti steel. The fatigue properties of 22MnSi2CrMoNi steel are excellent because of the following three reasons. First, at the initial stage of cyclic deformation, small plastic deformation occurs in the matrix. The highly stable film retained austenite does not undergo transformation. As cyclic deformation continues, the film retained austenite transforms to martensite, which effectively deactivates the crack tip. Second, 22MnSi2CrMoNi steel has higher yield strength. Fatigue damage is mainly caused by the irreversible motion of dislocations. Therefore, the fatigue damage of materials is inhibited during cyclic deformation.
During cyclic deformation, slipping and climbing of dislocations occur, and dislocation density increases, resulting in many dislocations accumulating between the slip plane and lath martensite [44]. When dislocation walls are connected end to end, dislocation cells are formed [45], and materials exhibit cyclic softening. Third, a small amount of ε-carbide diffusely distributed on lath martensite can effectively hinder the movement of dislocations [46]. Therefore, the LCF properties of 22MnSi2CrMoNi steel are excellent.
Under the same strain amplitude, the LCF lifetime of 22MnSi2CrMoNi steel is higher than that of 00Ni18Co9Mo4Ti steel. The residual austenite film between martensitic lath inhibits the crack propagation and improves the fatigue lifetime of 2MnSi2CrMoNi steel. The fatigue cracks of both steels originate from the sample surface. With the increase of the total strain amplitude, the fatigue fringe spacing increases significantly. The higher plastic strain amplitude of 22MnSi2CrMoNi steel than 00Ni18Co9Mo4Ti steel is the reason for its better fatigue performance.

4. Conclusions

In this paper, the LCF properties of a new low-carbon martensitic steel (22MnSi2CrMoNi) and martensitic aged steel (00Ni18Co9Mo4Ti) have been studied from the aspects of monotone mechanical properties, microstructure, LCF and fatigue lifetime prediction. The conclusions are as follows:
(1) 22MnSi2CrMoNi steel and 00Ni18Co9Mo4Ti steel have a similar cyclic deformation behavior. At a low total strain amplitude, the cyclic softening resistance of 22MnSi2CrMoNi steel is slightly inferior to that of 00Ni18Co9Mo4Ti steel, but this difference gradually disappears as the total strain amplitude increases;
(2) 22MnSi2CrMoNi steel and 00Ni18Co9Mo4Ti steel have a transition fatigue life of 1000 and 1183 cycles, respectively. Although the transition fatigue life of 22MnSi2CrMoNi steel is lower than that of 00Ni18Co9Mo4Ti steel, they belong to the same level. At the same plastic strain amplitude, the LCF life of 22MnSi2CrMoNi steel is longer than that of 00Ni18Co9Mo4Ti steel;
(3) 22MnSi2CrMoNi steel and 00Ni18Co9Mo4Ti steel at 1.0% total strain amplitude have formed dislocation cells in the lath martensite region within the specimen after fatigue failure. Dislocation cells are a manifestation of a low-energy state, and their appearance is conducive to the increase in plastic deformation capacity. That is, the material exhibits cyclic softening properties;
(4) The presence of film austenite between martensite laths, high yield strength, and precipitates in the matrix can effectively reduce the fatigue crack propagation rate of 22MnSi2CrMoNi steel; and
(5) The fatigue cracks of 22MnSi2CrMoNi steel and 00Ni18Co9Mo4Ti steel originate from the surface persistent slip bands of the specimen, and the variation in fatigue striations is the same at different total strain amplitudes. As the total strain amplitude increases, the fatigue striation spacing of the specimen increases significantly.

Author Contributions

Conceptualization, B.L., X.L. and S.X.; methodology, S.X. and G.Y.; data collection, S.X. and X.L.; data analysis, B.L. and F.Z.; writing—original draft preparation, B.L. and X.L.; writing—review and editing, F.Z. and G.Y. All authors have read and agreed to the published version of the manuscript.

Funding

The authors acknowledge financial support from the National Key R and D Program of China (2021YFB3703500), the National Natural Science Foundation of China (No. 52001275), the Natural Science Foundation of Hebei Province (E2020203084), and the Youth Talent Projects of Colleges in Hebei Province (BJ2020021).

Institutional Review Board Statement

Not applicable.

Informed Consent Statement

Not applicable.

Data Availability Statement

Not applicable.

Conflicts of Interest

The authors declare no conflict of interest.

References

  1. Kawagoishi, N.; Nagano, T.; Moriyama, M.; Kondo, E. Improvement of fatigue strength of maraging steel by shot peening. Mater. Manuf. Process. 2009, 24, 1431–1435. [Google Scholar] [CrossRef]
  2. Wang, W.; Yan, W.; Duan, Q.Q.; Shan, Y.Y.; Zhang, Z.F.; Yang, K. Study on fatigue property of a new 2.8 GPa grade maraging steel. Mater. Sci. Eng. A 2010, 527, 3057–3063. [Google Scholar] [CrossRef]
  3. Xu, Z.K.; Wang, B.; Zhang, P.; Zhang, Z.F. Short fatigue crack growth behavior in 18Ni marageing steel. Mater. Sci. Eng. A 2021, 807, 140844. [Google Scholar] [CrossRef]
  4. Wang, C.; Qiu, H.; Kimura, Y.; Inoue, T. Morphology, crystallography, and crack paths of tempered lath martensite in a medium-carbon low-alloy steel. Mater. Sci. Eng. A 2016, 669, 48–57. [Google Scholar] [CrossRef]
  5. Fonseca, D.P.M.D.; Larissa, A.; Feitosa, M.; Carvalho, L.G.D.; Padilha, A.F. A Short Review on Ultra-High-Strength Maraging Steels and Future Perspectives. Mater. Res. 2021, 24, 20200470. [Google Scholar] [CrossRef]
  6. Xia, S.L.; Zhang, F.C.; Zhang, C.Y.; Yang, Z.N. Mechanical properties and microstructures of a novel low-carbon high-silicon martensitic steel. ISIJ Int. 2017, 57, 558–563. [Google Scholar] [CrossRef]
  7. Seikh, A.H.; Halfa, H.; Soloman, M.S. Effect of Molybdenum content on the corrosion and microstructure of low-Ni, Co-free maraging steels. Metals 2021, 11, 852. [Google Scholar] [CrossRef]
  8. Zhang, F.C.; Lv, B.; Wang, T.S.; Zheng, C.L.; Zhang, M.; Luo, H. Microstructure and properties of purity high Mn steel crossing explosion hardened. ISIJ Int. 2008, 48, 1766–1770. [Google Scholar] [CrossRef]
  9. Kang, J.; Zhang, F.C.; Long, X.Y.; Lv, B. Cyclic deformation and fatigue behaviors of hadfield manganese steel. Mater. Sci. Eng. A 2014, 591, 59–68. [Google Scholar] [CrossRef]
  10. Zhang, Z.F.; Zhang, P.; Tian, Y.Z.; Zhang, Q.K.; Shen, Q.U.; Zou, H.F.; Duan, Q.Q.; Li, S.X.; Wang, Z.G. Interfacial effects of fatigue cracking in metallic materials. Acta Metall. Sin. 2009, 45, 788–800. [Google Scholar]
  11. Hong, Y.S.; Zhao, A.G.; Qian, G.A. Essential characteristics and influential factors for very-high-cycle fatigue behavior of metallic materials. Acta Metall. Sin. 2009, 45, 769–780. [Google Scholar]
  12. Liu, R.; Zhang, Z.J.; Zhang, P.; Zhang, Z.F. Extremely-low-cycle fatigue behaviors of Cu and Cu–Al alloys: Damage mechanisms and life prediction. Acta Mater. 2015, 83, 341–356. [Google Scholar] [CrossRef]
  13. Mishnev, R.; Dudova, N.; Kaibyshev, R. Effect of microstructural evolution on the cyclicsoftening of a 10% Cr martensitic steel under low cycle fatigue at 600 °C. Int. J. Fatigue 2020, 134, 105522. [Google Scholar] [CrossRef]
  14. Zhang, Z.; Hu, Z.; Schmauder, S.; Zhang, B.; Wang, Z. Low cycle fatigue properties and microstructure of P92 ferritic-martensitic steel at room temperature and 873 K. Mater. Charact. 2019, 157, 109923. [Google Scholar] [CrossRef]
  15. Jing, H.; Luo, Z.; Xu, L.; Zhao, L.; Han, Y. Low cycle fatigue behavior and microstructureevolution of a novel 9Cr–3W–3Co tempered martensitic steel at 650 °C. Mater. Sci. Eng. A 2018, 731, 394–402. [Google Scholar] [CrossRef]
  16. Verma, P.; Basu, J.; Srinivas, N.C.S.; Singh, V. Deformation behavior of modified 9Cr–1Mo steel under low cycle fatigue at 600 °C. Mater. Charact. 2017, 131, 244–252. [Google Scholar] [CrossRef]
  17. Golański, G.; Mrozi´nski, S. Low cycle fatigue and cyclic softening behaviour of martensitic cast steel. Eng. Fail. Anal. 2013, 35, 692–702. [Google Scholar] [CrossRef]
  18. Zhang, Q.; Zhang, J.; Zhao, P.; Huang, Y.; Yu, Z.; Fang, X. Low-cycle fatigue behaviors of a new type of 10% Cr martensitic steel and welded joint with Ni-based weld metal. Int. J. Fatigue 2016, 88, 78–87. [Google Scholar] [CrossRef]
  19. Bhadeshia, H.K.D.H.; Honeycombe, S.R. Steels, 3rd ed.; Elsevier Ltd.: Oxford, UK, 2006; p. 29. [Google Scholar]
  20. Luo, L.; Li, W.; Wang, L.; Zhou, S.; Jin, X. Tensile behaviors and deformation mechanism of a medium Mn-TRIP steel at different temperatures. Mater. Sci. Eng. A 2016, 682, 698–703. [Google Scholar] [CrossRef]
  21. Zhou, P.; Li, W.; Zhao, H.; Jin, X. Role of microstructure on electrochemical hydrogen permeation properties in advanced high strength steels. Int. J. Hydrogen Energy 2018, 43, 10905–10914. [Google Scholar] [CrossRef]
  22. Shao, C.W.; Zhang, P.; Liu, R.; Zhang, Z.J.; Pang, J.C.; Zhang, Z.F. Low-cycle and extremely-low-cycle fatigue behaviors of high-Mn austenitic TRIP/TWIP alloys: Property evaluation, damage mechanisms and life prediction. Acta Mater. 2016, 103, 781–795. [Google Scholar] [CrossRef]
  23. Zhang, X.; Wang, T.; Gong, X.; Li, Q.; Liu, Y.; Wang, Q.; Zhang, H.; Wang, Q. Low cycle fatigue properties, damage mechanism, life prediction and microstructure of MarBN steel: Influence of temperature. Int. J. Fatigue 2020, 144, 106070. [Google Scholar] [CrossRef]
  24. Ong, J.H. An improved technique for the prediction of axial fatique life from tensile data. Int. J. Fatigue 1993, 15, 213–219. [Google Scholar] [CrossRef]
  25. Manson, S.S. Fatigue: A complex subject—some simple approximations. Exp. Mech. 1965, 5, 193–226. [Google Scholar] [CrossRef]
  26. Shao, C.W.; Zhang, P.; Zhu, Y.K.; Zhang, Z.J.; Pang, J.C.; Zhang, Z.F. Improvement of low-cycle fatigue resistance in TWIP steel by regulating the grain size and distribution. Acta Mater. 2017, 134, 128–142. [Google Scholar] [CrossRef]
  27. Shankar, V.; Mariappan, K.; Nagesha, A.; Reddy, G.V.P.; Sandhya, R.; Mathew, M.D.; Jayakumar, T. Effect of tungsten and tantalum on the low cycle fatigue behavior of reduced activation ferritic/martensitic steels. Fusion Eng. Des. 2012, 87, 318–324. [Google Scholar] [CrossRef]
  28. Zhou, H.W.; He, Y.Z.; Zhang, H.; Yu, W. Influence of dynamic strain aging pre-treatment on the low-cycle fatigue behavior of modified 9Cr-1Mo steel. Int. J. Fatigue 2012, 47, 83–89. [Google Scholar] [CrossRef]
  29. Chen, L.J.; Wang, Z.G.; Yao, G.; Tian, J.F. The influence of temperature on low cycle fatigue behavior of nickel base superalloy gh4049. Int. J. Fatigue 1999, 21, 791–797. [Google Scholar] [CrossRef]
  30. Coffin, L.F. Fatigue at high temperature. Adv. Res. Strength Fract. Mater. 1978, 2, 263–292. [Google Scholar]
  31. Basquin, O.H. The Exponential Law of Endurance Test. Proc. Am. Soc. Test. Mater. 1910, 10, 625–630. [Google Scholar]
  32. Coffin, L.F. A study of the effects of cyclic thermal stresses on a ductile metal. Trans. Am. Soc. Test. Mater. 1954, 76, 931–950. [Google Scholar]
  33. Manson, S.S. Behavior of Materials under Conditions of Thermal Stress; Technical Report, No. 1170; National Advisory Committee for Aeronautics: Washington, DC, USA, 1953.
  34. Ellyin, F.; Kujawski, D. Plastic strain energy in fatigue failure. J. Press. Vessel Technol. 1984, 106, 342–347. [Google Scholar] [CrossRef]
  35. Abbasi, E.; Luo, Q.; Owens, D. A comparison of microstructure and mechanical properties of low-alloy-medium-carbon steels after quench-hardening. Mater. Sci. Eng. A 2018, 725, 65–75. [Google Scholar] [CrossRef]
  36. Long, X.Y.; Zhang, F.C.; Zhang, C.Y. Effect of Mn content on low-cycle fatigue behaviors of low-carbon bainitic steel. Mater. Sci. Eng. A 2017, 697, 111–118. [Google Scholar] [CrossRef]
  37. Wang, B.; Zhang, Z.J.; Shao, C.W.; Duan, Q.Q.; Pang, J.C.; Yang, H.J.; Li, X.W.; Zhang, Z.F. Improving the high-cycle fatigue lives of fe-30mn-0.9c twinning-induced plasticity steel through pre-straining, Metall. Met. Mater. Trans. A 2015, 46, 3317–3323. [Google Scholar] [CrossRef]
  38. Wang, B.; Zhang, P.; Duan, Q.Q.; Zhang, Z.J.; Yang, H.J.; Li, X.W.; Zhang, Z.F. Optimizing the fatigue strength of 18ni maraging steel through ageing treatment. Mater. Sci. Eng. A 2017, 707, 674–688. [Google Scholar] [CrossRef]
  39. Mughrabi, H. Cyclic slip irreversibility and fatigue life: A microstructure-based analysis. Acta Mater. 2013, 61, 1197–1203. [Google Scholar] [CrossRef]
  40. Dickson, J.I.; Boutin, J.; Handfield, L. A comparison of two simple methods for measuring cyclic internal and effective stresses. Mater. Sci. Eng. 1984, 64, L7–L11. [Google Scholar] [CrossRef]
  41. Neumann, P. Coarse slip model of fatigue. Acta Met. 1969, 17, 1219–1225. [Google Scholar] [CrossRef]
  42. Kang, J.; Zhang, F.C.; Long, X.Y.; Lv, B. Low cycle fatigue behavior in a medium-carbon carbide-free bainitic steel. Mater. Sci. Eng. A 2016, 666, 88–93. [Google Scholar] [CrossRef]
  43. Liu, H.; Sun, J.; Jiang, T.; Guo, S.; Liu, Y.; Lin, X. Rolling contact fatigue behavior of an ultrahigh carbon steel. Acta Metall. Sin. 2014, 50, 1446–1452. [Google Scholar]
  44. Huo, C.Y.; Gao, H.L. Strain-induced martensitic transformation in fatigue crack tip zone for a high strength steel. Mater. Charact. 2015, 55, 12–18. [Google Scholar] [CrossRef]
  45. Che, X.; Liang, X.; Chen, L.; Li, F. Microstructures and low-cycle fatigue behavior of al-9.0%si-4.0%cu-0.4%mg(-0.3%sc) alloy. Acta Metall. Sin. 2014, 50, 1046–1054. [Google Scholar]
  46. Abareshi, M.; Emadoddin, E. Effect of retained austenite characteristics on fatigue behavior and tensile properties of transformation induced plasticity steel. Mater. Des. 2011, 32, 5099–5105. [Google Scholar] [CrossRef]
Coatings 12 00818 g001 550
Figure 1. Geometry of LCF specimen (unit in mm).
Figure 1. Geometry of LCF specimen (unit in mm).
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Figure 2. TEM micrographs of 22MnSi2CrMoNi (a) and 00Ni18Co9Mo4Ti (b) steel (RA: Retained Austenite).
Figure 2. TEM micrographs of 22MnSi2CrMoNi (a) and 00Ni18Co9Mo4Ti (b) steel (RA: Retained Austenite).
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Figure 3. Engineering stress–strain curves of 22MnSi2CrMoNi and 00Ni18Co9Mo4Ti steel.
Figure 3. Engineering stress–strain curves of 22MnSi2CrMoNi and 00Ni18Co9Mo4Ti steel.
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Figure 4. Cyclic stress response curves of (a) 22MnSi2CrMoNi and (b) 00Ni18Co9Mo4Ti steels (the built-in partial enlargement diagram shows the cyclic deformation behavior from 0 to 2000 cycles).
Figure 4. Cyclic stress response curves of (a) 22MnSi2CrMoNi and (b) 00Ni18Co9Mo4Ti steels (the built-in partial enlargement diagram shows the cyclic deformation behavior from 0 to 2000 cycles).
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Figure 5. Cyclic softening rate versus strain range of 22MnSi2CrMoNi and 00Ni18Co9Mo4Ti steel.
Figure 5. Cyclic softening rate versus strain range of 22MnSi2CrMoNi and 00Ni18Co9Mo4Ti steel.
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Figure 6. Plastic strain amplitude, elastic strain amplitude and total strain amplitude versus the number of reversals to failure of (a) 22MnSi2CrMoNi and (b) 00Ni18Co9Mo4Ti steels.
Figure 6. Plastic strain amplitude, elastic strain amplitude and total strain amplitude versus the number of reversals to failure of (a) 22MnSi2CrMoNi and (b) 00Ni18Co9Mo4Ti steels.
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Figure 7. Curves of (a) plastic strain amplitude, (b) total strain amplitude, (c) stress amplitude, and (d) hysteresis energy versus the number of reversals to failure of 22MnSi2CrMoNi and 00Ni18Co9Mo4Ti steel.
Figure 7. Curves of (a) plastic strain amplitude, (b) total strain amplitude, (c) stress amplitude, and (d) hysteresis energy versus the number of reversals to failure of 22MnSi2CrMoNi and 00Ni18Co9Mo4Ti steel.
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Figure 8. Evolution of the (a) internal stress and (b) effective stress with the number of cycles of 22MnSi2CrMoNi steel, (c) internal stress, and (d) effective stress versus the number of cycles of 00Ni18Co9Mo4Ti steel.
Figure 8. Evolution of the (a) internal stress and (b) effective stress with the number of cycles of 22MnSi2CrMoNi steel, (c) internal stress, and (d) effective stress versus the number of cycles of 00Ni18Co9Mo4Ti steel.
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Figure 9. Dislocation observations of (a) 22MnSi2CrMoNi and (b) 00Ni18Co9Mo4Ti steels after fracture at 1.0% total strain amplitude.
Figure 9. Dislocation observations of (a) 22MnSi2CrMoNi and (b) 00Ni18Co9Mo4Ti steels after fracture at 1.0% total strain amplitude.
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Figure 10. Micro-morphologies of crack initiation zone at 0.52% total strain amplitude (a) 22MnSi2CrMoNi steel and (b) 00Ni18Co9Mo4Ti steel.
Figure 10. Micro-morphologies of crack initiation zone at 0.52% total strain amplitude (a) 22MnSi2CrMoNi steel and (b) 00Ni18Co9Mo4Ti steel.
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Figure 11. Micro-morphologies of crack growth zone of 22MnSi2CrMoNi steel at (a) 0.52%, (c) 0.8%, (e) 1.0% total strain amplitude; Micro-morphologies of crack growth zone of 00Ni18Co9Mo4Ti steel at (b) 0.52%, (d) 0.8%, and (f) 1.0% total strain amplitude.
Figure 11. Micro-morphologies of crack growth zone of 22MnSi2CrMoNi steel at (a) 0.52%, (c) 0.8%, (e) 1.0% total strain amplitude; Micro-morphologies of crack growth zone of 00Ni18Co9Mo4Ti steel at (b) 0.52%, (d) 0.8%, and (f) 1.0% total strain amplitude.
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Table
Table 1. Chemical compositions of tested steels (wt.%).
Table 1. Chemical compositions of tested steels (wt.%).
SteelCMnNiCoMoSiCrTi
22MnSi2CrMoNi0.211.080.14-0.191.790.740.003
00Ni18Co9Mo4Ti<0.001<0.00117.508.44.320.010.120.182
Table
Table 2. Mechanical properties of 22MnSi2CrMoNi and 00Ni18Co9Mo4Ti steel.
Table 2. Mechanical properties of 22MnSi2CrMoNi and 00Ni18Co9Mo4Ti steel.
SteelHRCσs (MPa)σb (MPa)δ (%)akU (J/cm2)δ × σb (GPa·%)
22MnSi2CrMoNi48.31261 ± 81548 ± 1413.2 ± 0.4120 ± 716.6
00Ni18Co9Mo4Ti44.91426 ± 91496 ± 1511.6 ± 0.3105 ± 816.5
σb: ultimate tensile strength; σs: yield strength; δ: elongation; akU: impact toughness; and δ × σb: static toughness.
Table
Table 3. Parameter values of LCF test for 22MnSi2CrMoNi and 00Ni18Co9Mo4Ti steel.
Table 3. Parameter values of LCF test for 22MnSi2CrMoNi and 00Ni18Co9Mo4Ti steel.
Tested
Steel		 σ f ′
(MPa)		 b ε f ′
(mm/mm)		 c W 0
(MJ/m3)		 β
22MnSi2CrMoNi2114−0.744−0.923612.93
00Ni18Co9Mo4Ti3437−0.12213−1.494882.73
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Lv, B.; Xia, S.; Zhang, F.; Yang, G.; Long, X. Comparison of Novel Low-Carbon Martensitic Steel to Maraging Steel in Low-Cycle Fatigue Behavior. Coatings 2022, 12, 818. https://doi.org/10.3390/coatings12060818

AMA Style

Lv B, Xia S, Zhang F, Yang G, Long X. Comparison of Novel Low-Carbon Martensitic Steel to Maraging Steel in Low-Cycle Fatigue Behavior. Coatings. 2022; 12(6):818. https://doi.org/10.3390/coatings12060818

Chicago/Turabian Style

Lv, Bo, Shule Xia, Fucheng Zhang, Guang Yang, and Xiaoyan Long. 2022. "Comparison of Novel Low-Carbon Martensitic Steel to Maraging Steel in Low-Cycle Fatigue Behavior" Coatings 12, no. 6: 818. https://doi.org/10.3390/coatings12060818

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