International Journal of Fatigue最新文献_第4页

Effect of shot peening on surface integrity and elevated temperature fatigue behavior of ATI 718Plus alloy 喷丸强化对ATI 718Plus合金表面完整性和高温疲劳性能的影响

IF 6.8 2区材料科学 Q1 ENGINEERING, MECHANICAL

International Journal of Fatigue

Pub Date : 2026-02-01 DOI: 10.1016/j.ijfatigue.2026.109527

Jianxin Luo , Changfeng Yao , Liming Lei , Liang Tan

As a well established surface strengthening technology for improving the fatigue performance of critical components, this study focuses on the new-generation superalloy ATI 718Plus and systematically investigates the influence law of shot peening on its surface integrity and high-temperature fatigue performance. Intense plastic deformation not only introduces a residual compressive stress field with high amplitude and a significant work-hardened layer but also causes the surface topography to become more complex.. The research results show that after shot peening, the maximum surface microhardness of the material can reach 569.95 HV0.05, which is 20% higher than the hardness of the baseline material; the maximum residual compressive stress in the surface layer can reach -1357.5 MPa, which greatly enhances the material surface’s resistance to fatigue crack initiation. Under the fatigue test environment of 650℃, the average rotating bending fatigue life of the shot-peened specimens is twice that of the unpeened specimens. Microscopic analysis of fatigue fracture surfaces further clarifies its life extension mechanism: the residual compressive stress field and hardened layer generated by shot peening cause the initiation location of fatigue sources to migrate toward the interior of the material, hindering the formation and propagation of fatigue cracks and thereby improving the fatigue life of the specimens. This study clarifies the surface integrity characteristics of 718Plus alloy induced by shot peening and reveals the transformation of its elevated-temperature fatigue failure mechanism from the perspective of fatigue crack initiation control.

作为一种成熟的改善关键部件疲劳性能的表面强化技术，本研究以新一代高温合金ATI 718Plus为研究对象，系统研究了喷丸强化对其表面完整性和高温疲劳性能的影响规律。强烈的塑性变形不仅会产生高振幅的残余压应力场和显著的加工硬化层，而且会使表面形貌变得更加复杂。研究结果表明：喷丸强化后，材料的最大表面显微硬度可达569.95 HV0.05，比基准材料硬度提高20%；表层最大残余压应力可达-1357.5 MPa，大大增强了材料表面抗疲劳裂纹萌生的能力。在650℃的疲劳试验环境下，喷丸试样的平均旋转弯曲疲劳寿命是未喷丸试样的2倍。疲劳断口表面的微观分析进一步阐明了其延长寿命的机理：喷丸强化产生的残余压应力场和硬化层使疲劳源的起始位置向材料内部迁移，阻碍了疲劳裂纹的形成和扩展，从而提高了试样的疲劳寿命。本研究阐明了喷丸处理后718Plus合金的表面完整性特征，并从疲劳裂纹萌生控制的角度揭示了718Plus合金高温疲劳失效机理的转变。

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引用次数: 0

Physics-informed deep neural network framework for prediction of fatigue crack growth in LPBF-manufactured metallic alloys 基于物理信息的深度神经网络框架预测lpbf制造的金属合金疲劳裂纹扩展

IF 6.8 2区材料科学 Q1 ENGINEERING, MECHANICAL

International Journal of Fatigue

Pub Date : 2026-01-31 DOI: 10.1016/j.ijfatigue.2026.109522

A. Ince

A baseline Deep Neural Network (DNN) and two Physics-Informed Neural Networks (PINN-R and PINN-K_max) were developed for predicting fatigue crack growth rates (da/dN) in Ti–6Al–4V, IN625, and 17-4PH alloys produced by laser powder bed fusion (LPBF). Unlike traditional analytical models that rely only on driving force parameters such as ΔK and R, the network models integrate process parameters, mechanical properties, and fracture mechanics driving forces to capture complex interdependencies between manufacturing, material behavior, and crack growth response. The PINN models enforce monotonic constraints on the crack growth rate with respect to ΔK and either R (PINN-R) or the maximum stress-intensity factor K_max (PINN-K_max) by ensuring physical consistency while improving generalization. Models’ performance is assessed under two data splitting methods based on random K-fold cross-validation and grouped split by dataset IDs. A classical Walker model fitted on the same data provided a fracture-mechanics baseline. Under both data split methods, predictions from all neural models mainly fall within a ±3 × scatter band for all three alloys. The PINNs, particularly PINN-K_max generally achieved better performance with lower RMSE and higher R² than the baseline DNN and Walker model, especially in the Paris and rapid-growth regimes. The results highlight the novelty of embedding physics into data-driven models by indicating a robust, physics-aware machine learning framework for fatigue crack growth prediction in LPBF alloys.

建立了一个基线深度神经网络（DNN）和两个物理信息神经网络（PINN-R和PINN-Kmax），用于预测激光粉末床熔化（LPBF）生产的Ti-6Al-4V， IN625和17-4PH合金的疲劳裂纹扩展速率（da/dN）。与仅依赖于驱动力参数（如ΔK和R）的传统分析模型不同，网络模型集成了工艺参数、机械性能和断裂力学驱动力，以捕获制造、材料行为和裂纹扩展响应之间复杂的相互依赖关系。PINN模型在保证物理一致性的同时提高了通用性，从而对ΔK和R （PINN-R）或最大应力强度因子Kmax （PINN-Kmax）的裂纹扩展速率施加单调约束。在随机k折交叉验证和按数据集id分组分割两种数据分割方法下，对模型的性能进行了评估。基于相同数据的经典Walker模型提供了断裂力学基线。在两种数据分割方法下，所有神经模型对所有三种合金的预测主要落在±3 ×散射带内。与基线DNN和Walker模型相比，pinn，特别是PINN-Kmax通常在RMSE较低和R2较高的情况下获得更好的性能，特别是在巴黎和快速增长制度下。研究结果强调了将物理嵌入数据驱动模型的新颖性，为LPBF合金的疲劳裂纹扩展预测提供了一个强大的、物理感知的机器学习框架。

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引用次数: 0

Prediction of residual life and critical crack length using the forward/inverse machine learning based on the configurational force fatigue model 基于构形力疲劳模型的正反向机器学习预测残余寿命和临界裂纹长度

IF 6.8 2区材料科学 Q1 ENGINEERING, MECHANICAL

International Journal of Fatigue

Pub Date : 2026-01-31 DOI: 10.1016/j.ijfatigue.2026.109525

Yingxuan Dong , Ran Liu , Qun Li

For mixed-mode fatigue cracks commonly found in engineering structures, classical empirical fatigue models struggle to accurately assess nonlinear propagation characteristics and fatigue life under complex stress states. To address this limitation, this study develops a physics-informed neural network (PINN) integrated with a configurational force fatigue model to predict mixed-mode fatigue crack propagation and remaining life in ductile metallic materials via a forward/inverse machine-learning framework. The proposed methodology overcomes the limited applicability of traditional fatigue models to mixed-mode cracking while enhancing the extrapolation capability of purely data-driven methods through physics-based constraints derived from fatigue crack growth mechanisms. Numerical results demonstrate accurate remaining life predictions for both mode-I and I-II mixed-mode fatigue cracks. Furthermore, based on the established correlation between the crack length and the residual life, a genetic algorithm is employed to perform the inverse machine learning process. The critical fatigue crack lengths for I-II mixed-mode cracks at various deflection angles are inversely identified from the zero remaining life. This work establishes a novel PINN framework based on the configurational force theory, achieving integrated and accurate predictions of both the propagation and remaining life of mixed-mode fatigue cracks.

对于工程结构中常见的混合模态疲劳裂纹，传统的经验疲劳模型难以准确评估复杂应力状态下的非线性扩展特性和疲劳寿命。为了解决这一限制，本研究开发了一个物理信息神经网络（PINN），该网络与配置力疲劳模型相结合，通过正/逆机器学习框架预测延性金属材料的混合模式疲劳裂纹扩展和剩余寿命。该方法克服了传统疲劳模型对混合模式裂纹适用性的局限性，同时通过疲劳裂纹扩展机制的物理约束增强了纯数据驱动方法的外推能力。数值结果表明，i型和I-II型混合模态疲劳裂纹的剩余寿命预测是准确的。此外，基于已建立的裂纹长度与剩余寿命之间的相关性，采用遗传算法进行逆机器学习。在剩余寿命为零的情况下，可以反求出I-II型混合模裂纹在不同挠度下的临界疲劳裂纹长度。本文基于构形力理论建立了一种新的PINN框架，实现了对混合模态疲劳裂纹扩展和剩余寿命的综合准确预测。

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引用次数: 0

A combined rolling contact fatigue damage mechanism for EMU train axle box bearings 动车组列车轴箱轴承组合滚动接触疲劳损伤机理研究

IF 6.8 2区材料科学 Q1 ENGINEERING, MECHANICAL

International Journal of Fatigue

Pub Date : 2026-01-31 DOI: 10.1016/j.ijfatigue.2026.109533

Zhewei Zhang , Zilong Chen , Yi Wu , Hanwei Fu

The fatigue fracture of bearings is a major threat to the service safety of EMU trains. This study systematically investigates the evolution of spalling in axle box bearing outer rings through detailed characterization and in-depth analysis, proposing a combined rolling contact mechanism. Two distinct regions are identified in the spalls, respectively corresponding to subsurface- and surface-induced rolling contact fatigue (RCF) damages. Crack propagation and branching behaviors are thoroughly revealed in different spalling regions. According to this study, spalling begins with subsurface cracks originating at the depth consistent with the peak maximum shear stress under Hertzian contact, forming concentric ellipses with deep pits. As spalling progresses, surface-initiated cracks from spall-edge stress concentration can lead to further, shallow material removal that broadens with increasing over-rolling cycles. Electron backscatter diffraction and nanoindentation show that local microstructural refinement and hardening occur along with crack formation. A critical threshold stress intensity factor that dominates RCF crack growth is found, which is crucial for RCF modelling and life prediction. The study also identifies two crack-carbide interaction modes, cutting-through and bypassing, with the transition between them determined by a critical carbide diameter of 1 µm. These findings provide crucial insight into the RCF mechanism and offer practical guidance for long-life railway bearing steels.

轴承疲劳断裂是动车组列车运行安全的主要威胁。本研究通过详细的表征和深入的分析，系统地研究了轴箱轴承外圈剥落的演变过程，提出了一种组合滚动接触机制。在碎片中确定了两个不同的区域，分别对应于地下和表面引起的滚动接触疲劳（RCF）损伤。裂纹扩展和分支行为在不同的剥落区域得到了全面的揭示。根据本研究，剥落始于与赫兹接触下最大剪应力峰值一致深度的地下裂纹，形成带有深坑的同心椭圆。随着剥落的进行，剥落边缘应力集中引起的表面裂纹可能导致进一步的、浅的材料去除，并且随着过滚循环次数的增加而扩大。电子背散射衍射和纳米压痕分析表明，裂纹形成过程中出现了局部组织的细化和硬化。发现了控制RCF裂纹扩展的临界阈值应力强度因子，这对RCF建模和寿命预测具有重要意义。该研究还确定了两种裂纹-碳化物相互作用模式，即切割和旁路，它们之间的过渡由1 μ m的临界碳化物直径决定。这些发现对RCF机制提供了重要的见解，并为长寿命铁路轴承钢提供了实用指导。

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引用次数: 0

Fatigue of additively manufactured 18Ni300 maraging steel 增材制造18Ni300马氏体时效钢的疲劳性能

IF 6.8 2区材料科学 Q1 ENGINEERING, MECHANICAL

International Journal of Fatigue

Pub Date : 2026-01-30 DOI: 10.1016/j.ijfatigue.2026.109529

Paschalis Adamidis, Antonios Tsakiris, Georgios Savaidis

This study investigates the fatigue behavior of 18Ni300 maraging steel fabricated via Laser Powder Bed Fusion (LPBF) and subjected to a novel, cost-effective two-stage heat treatment performed in an air atmosphere. The specimens underwent solution annealing at 940°C for 1 h followed by aging at 490°C for 6 h. Monotonic tensile tests revealed that this thermal treatment significantly enhances mechanical strength, increasing the yield strength by 86% and the ultimate tensile strength by 70% compared to the as-built condition, although ductility decreases from 4.7% to 2.6%. Fatigue test results demonstrated superior fatigue resistance compared to similar datasets from literature for both as-built and conventionally heat-treated conditions. Microstructural analysis confirmed that the studied air-atmosphere thermal process effectively dissolved the laser-induced melt pool boundaries, resulting in a homogenized martensitic matrix, but with a notable fraction of reverted austenite. Fractographic examination identified that fatigue failure was driven predominantly by non-metallic inclusions located just beneath the surface. The findings suggest that while air-furnace heat treatment is a viable, low-cost method for restoring static strength, the fatigue life of AM maraging steel remains sensitive to oxide inclusions which persist as stress concentrators within the hardened matrix.

本研究研究了激光粉末床熔合（LPBF）制备的18Ni300马氏体时效钢的疲劳行为，并在空气气氛中进行了一种新颖的、经济有效的两阶段热处理。试样在940℃固溶退火1 h，然后在490℃时效6 h。单调拉伸试验表明，这种热处理显著提高了机械强度，与原状相比，屈服强度提高了86%，极限抗拉强度提高了70%，但延展性从4.7%下降到2.6%。疲劳测试结果表明，与文献中类似的数据集相比，无论是在预制条件下还是在常规热处理条件下，该材料都具有更好的抗疲劳性能。显微组织分析证实，所研究的空气-大气热过程有效地溶解了激光诱导的熔池边界，产生均匀的马氏体基体，但有显著比例的还原奥氏体。断口学检查发现，疲劳失效主要是由位于表面以下的非金属夹杂物引起的。研究结果表明，虽然空气炉热处理是一种可行的、低成本的恢复静态强度的方法，但AM马氏体时效钢的疲劳寿命仍然对氧化物夹杂物敏感，这些夹杂物在硬化基体中作为应力集中剂存在。

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引用次数: 0

Enhancing fatigue life of L12-strengthened multi-principal element alloy by tailoring grain boundary characteristics and precipitation 通过调整晶界特征和析出来提高l12强化多主元素合金的疲劳寿命

IF 6.8 2区材料科学 Q1 ENGINEERING, MECHANICAL

International Journal of Fatigue

Pub Date : 2026-01-30 DOI: 10.1016/j.ijfatigue.2026.109523

Shaoxin Cai , Jingping Cui , Baijun Yang , Dong Han , Jianqiang Wang

A significant challenge has recently been highlighted in L1₂-strengthened multi-principal element alloys (MPEAs), where the Al-Ti-bearing systems are prone to forming the coarse-sized discontinuous precipitates (DPs) along grain boundaries (GBs) during aging. This intensifies the strain localization near GBs, thus posing a potential threat to the fatigue performance of the alloy, as reported in traditional alloys. To address this, the grain boundary engineering (GBE) strategy was applied to a (NiCoCr)₉₄Al₃Ti₃ MPEA through simple thermomechanical treatment, and its influence on DPs and the resulting tension–tension fatigue behavior was systematically examined. The results reveal that GBE treatment can significantly increase the fraction of special boundaries dominated by Σ3 boundaries and disrupt the connectivity of random high-angle grain boundaries, thereby effectively inhibiting the formation of DPs. Such a microstructure optimization leads to a 2–4 times improvement in the fatigue life, depending on the stress amplitudes. The enhanced properties are attributed to the synergistic role of modified GB characteristics and DP suppression. This effect promotes the deformation uniformity and alleviates the strain incompatibility between the two sides of boundaries, thus enhancing crack initiation and propagation resistance. Our work provides a simple yet effective pathway for improving the fatigue performance of L1₂-strengthened MPEAs, particularly under high-stress amplitudes where GB cracking is the dominant failure mode.

l12强化多主元素合金（MPEAs）在时效过程中容易沿晶界（GBs）形成粗尺寸的不连续相（DPs）。这加剧了GBs附近的应变局部化，从而对合金的疲劳性能构成了潜在的威胁，正如传统合金所报道的那样。为了解决这一问题，通过简单的热处理将晶界工程（GBE）策略应用于（NiCoCr）94Al3Ti3 MPEA，并系统地研究了其对DPs和由此产生的拉伸-拉伸疲劳行为的影响。结果表明，GBE处理可以显著增加Σ3晶界主导的特殊晶界的比例，破坏随机高角度晶界的连性，从而有效抑制DPs的形成。这种微观结构优化导致疲劳寿命提高2-4倍，具体取决于应力幅值。性能的增强是由于改性的GB特性和DP抑制的协同作用。这种作用促进了变形均匀性，缓解了边界两侧的应变不相容，从而增强了裂纹起裂和扩展的阻力。我们的工作为提高l12强化mpea的疲劳性能提供了一个简单而有效的途径，特别是在高应力幅下，GB裂纹是主要的破坏模式。

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引用次数: 0

The effects of austempering time on mechanical properties of the novel GCr15Si1MoNbV bearing steel and on its rolling contact fatigue behaviors 等温回火时间对新型GCr15Si1MoNbV轴承钢力学性能及滚动接触疲劳行为的影响

IF 6.8 2区材料科学 Q1 ENGINEERING, MECHANICAL

International Journal of Fatigue

Pub Date : 2026-01-28 DOI: 10.1016/j.ijfatigue.2026.109519

Yanhui Wang , Ziqi Liu , Xubiao Wang , Xiang Chen , Xiliang Zhang , Wenfei Shen , Qian Yang , Leijie Zhao , Zhinan Yang

Rolling contact fatigue (RCF) is a critical failure mode of bearings. In this study, the novel GCr15Si1MoNbV bearing steel was subjected to low-temperature salt-bath austempering, and the effects of phase transformation during austempering on microstructure, mechanical properties and RCF behavior were investigated experimentally using scanning electron microscopy (SEM), transmission electron microscopy (TEM), electron backscatter diffraction (EBSD), and RCF testing. The specimen austempered at 190 °C for 10 h with a multiphase microstructure composed of nanobainite, martensite, and a high volume fraction of retained austenite exhibited exceptional performance. This kind of multiphase microstructure provided high surface hardness, excellent impact toughness, and a favorable residual stress gradient characterized by compressive stress at surface and tensile stress at subsurface, which collectively delayed crack initiation and propagation. As a result, the basic rating life (L₁₀), the median life (L₅₀), and the characteristic life (V_s) of the martensite–nanobainite–austenite 10 h specimen were 2–3 times to those of the martensite-dominated 2 h specimen, and 3–5 times to those of the nanobainite-dominated 48 h specimen. These findings indicate that the synergistic optimization of multiphase microstructure and residual stress gradient is the key mechanism for enhancing the RCF performance of bearing steels.

滚动接触疲劳（RCF）是轴承的一种关键失效模式。对新型GCr15Si1MoNbV轴承钢进行低温盐浴等温回火，利用扫描电镜（SEM）、透射电镜（TEM）、电子背散射衍射（EBSD）和RCF测试，研究了等温回火过程中相变对钢组织、力学性能和RCF行为的影响。样品在190℃下等温10 h，形成由纳米贝氏体、马氏体和大量残余奥氏体组成的多相组织，表现出优异的性能。这种多相组织具有高的表面硬度、优异的冲击韧性和良好的残余应力梯度，其特征为表面压应力和亚表面拉应力，共同延缓了裂纹的萌生和扩展。结果表明，马氏体-纳米贝氏体-奥氏体10 h试样的基本额定寿命（L10）、中位寿命（L50）和特征寿命（Vs）分别是马氏体为主的2 h试样的2 ~ 3倍、纳米贝氏体为主的48 h试样的3 ~ 5倍。研究结果表明，多相组织和残余应力梯度的协同优化是提高轴承钢RCF性能的关键机制。

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引用次数: 0

Defect-based multiaxial fatigue life assessment of 3D-printed bulk metallic glasses 基于缺陷的3d打印大块金属玻璃多轴疲劳寿命评估

IF 6.8 2区材料科学 Q1 ENGINEERING, MECHANICAL

International Journal of Fatigue

Pub Date : 2026-01-27 DOI: 10.1016/j.ijfatigue.2026.109528

Songyun Ma , Hongshi Ruan , Jianye Shi , Cécile Chaxel , Shuai Wei , Moritz Stolpe , Peilei Zhang , Yangjian Xu , Bernd Markert

Additive manufacturing unlocks near-net-shape production of bulk metallic glass (BMG) components with complex geometries. Nevertheless, their durability under multiaxial cyclic loadings remains largely unexplored and poorly understood. In this work, the multiaxial fatigue behaviour of selective laser melting (SLM) fabricated Zr-based BMG with composition

{Zr}_{59.3} {Cu}_{28.8} {Nb}_{1.5} {Al}_{10.4}

is investigated. In multiaxial fatigue experiments, 17 specimens with approximately 0.46% porosity were subjected to stress-controlled cyclic loadings, including both proportional and non-proportional loading paths. The fracture morphology and multiaxial fatigue mechanisms were systematically analysed using SEM micrographs. To evaluate the fatigue life of 3D-printed BMGs while accounting for manufacturing-induced defects, we conducted defect-based computational simulations using representative volume element (RVE) models incorporating a single pore defect. Parametric studies were carried out to examine the influence of pore location on multiaxial fatigue life performance. Based on the FEM simulation results, a modified non-local Dang Van criterion is proposed for predicting the multiaxial fatigue life. In the critical plane model, a non-proportional correction coefficient is introduced based on the principal stress at the critical location in the vicinity of the defect to enhance the prediction accuracy. The results demonstrate that the proposed model can predict the multiaxial fatigue life of 3D-printed BMG with satisfactory accuracy.

增材制造解锁了具有复杂几何形状的大块金属玻璃（BMG）组件的近净形状生产。然而，它们在多轴循环载荷下的耐久性在很大程度上仍未被探索和了解。研究了选择性激光熔化zr59 .3 cu28 .8 nb1.5 . al10.4 zr基BMG的多轴疲劳行为。在多轴疲劳试验中，选取17个孔隙率约为0.46%的试件进行应力控制循环加载，包括比例加载路径和非比例加载路径。利用扫描电镜对断口形貌和多轴疲劳机理进行了系统分析。为了评估3d打印bmg的疲劳寿命，同时考虑到制造引起的缺陷，我们使用包含单孔缺陷的代表性体积元（RVE）模型进行了基于缺陷的计算模拟。通过参数化研究考察了孔隙位置对多轴疲劳寿命性能的影响。在有限元模拟结果的基础上，提出了一种改进的非局部Dang Van准则来预测多轴疲劳寿命。在临界平面模型中，根据缺陷附近临界位置的主应力引入非比例修正系数，提高了预测精度。结果表明，该模型能较好地预测3d打印BMG的多轴疲劳寿命。

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引用次数: 0

A 2.9 GPa modified M50 steel with Remarkably high fatigue strength by Nb and Al alloying 采用Nb和Al合金化改性了一种GPa为2.9的M50钢，具有很高的疲劳强度

IF 6.8 2区材料科学 Q1 ENGINEERING, MECHANICAL

International Journal of Fatigue

Pub Date : 2026-01-27 DOI: 10.1016/j.ijfatigue.2026.109518

Jing Zhang , Qingfeng Kang , Hui Wang , Zexi Zhang , Wenquan Cao

Coarse prior austenite grains and large primary carbides are the main reasons for the limited strength and poor fatigue performance of M50 steel. In this study, the addition of Nb and Al to M50 steel was designed, leading to the simultaneous refinement of both the prior austenite grains (to 8.55 ± 0.58 μm) and the largest primary carbides (to 20 μm). Furthermore, the modified steel exhibited extremely excellent tensile strength (R_m: 2864 ± 49 MPa and R_p0.2: 2502 ± 22 MPa) and rotating bending fatigue strength (R_-1 = 1153 MPa). Microstructural characterization further revealed that alloying with Nb and Al synergistically altered the precipitation sequence during tempering, which suppressed Fe₃C precipitation and spheroidization, and instead promoted the formation of a dense and uniform distribution of nanoscale M₂C carbides, thereby significantly enhancing the tensile strength. Additionally, the Nb and Al alloying refined the primary MC and M₂C carbides by inhibiting eutectic reactions and promoting the high-temperature decomposition of eutectic carbides. Consequently, this pronounced carbide refinement shifted fatigue crack initiation away from the carbide-dominated fracture sites (typical of conventional M50 steel) to weak microstructural regions within the modified steel’s matrix, thereby markedly increasing fatigue strength. These weak structures were associated with local chemical inhomogeneities and strain concentration at martensite packets and blocks boundaries. In summary, this systematic investigation into the effects of Nb and Al alloying on the microstructure evolution, mechanical properties, and fatigue behavior of M50 steel offers a promising strategy for developing high-temperature bearing steels with ultrahigh strength and excellent fatigue performance.

粗的奥氏体晶粒和大的初生碳化物是造成M50钢强度有限、疲劳性能差的主要原因。在本研究中，设计了在M50钢中添加Nb和Al的方法，使先前的奥氏体晶粒（细化到8.55 ± 0.58 μm）和最大的初生碳化物（细化到20 μm）同时细化。此外,修改后的钢表现出非常优秀的抗拉强度(Rm: 2864 ± 49 MPa和Rp0.2: 2502 ± 22 MPa)和旋转弯曲疲劳强度(r 1 = 1153 MPa)。显微组织表征进一步表明，Nb和Al的合金化协同改变了回火过程中的析出顺序，抑制了Fe3C的析出和球化，促进了致密均匀分布的纳米级M2C碳化物的形成，从而显著提高了抗拉强度。Nb和Al合金通过抑制共晶反应和促进共晶碳化物的高温分解来细化初生MC和M2C碳化物。因此，这种明显的碳化物细化将疲劳裂纹的起裂点从碳化物主导的断裂部位（典型的传统M50钢）转移到改性钢基体内的弱显微组织区域，从而显著提高了疲劳强度。这些弱结构与局部化学不均匀性和马氏体包和块边界的应变浓度有关。综上所述，本文系统研究了Nb和Al合金对M50钢组织演变、力学性能和疲劳行为的影响，为开发具有超高强度和优异疲劳性能的高温轴承钢提供了有希望的策略。

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引用次数: 0

Plastic strain energy-based corrosion fatigue crack propagation modeling in 18Ni (250) welded joints 基于塑性应变能的18Ni（250）焊接接头腐蚀疲劳裂纹扩展模型

IF 6.8 2区材料科学 Q1 ENGINEERING, MECHANICAL

International Journal of Fatigue

Pub Date : 2026-01-26 DOI: 10.1016/j.ijfatigue.2026.109516

Yongmei Zhu , Dan Meng , Xilu Zhao

Corrosion fatigue crack propagation (CFCP) in welded joints of deep-sea structures governs their structural integrity under prolonged exposure to aggressive marine environments. To address this, this study investigates CFCP in 18Ni (250) maraging steel welded joints by establishing a crack growth rate model driven by plastic strain energy. Four specimens were fabricated and underwent fatigue testing in simulated seawater (3.5% NaCl solution), quantifying crack growth life at stress ratios of 0.1 and 0.3. Digital image correlation characterized crack-tip cyclic plastic zone evolution, revealing strain/stress amplitudes and plastic strain energy distributions. Cyclic plastic zone behavior was analyzed to derive plastic strain energy, forming the basis of a CFCP rate model. Numerical simulations of crack growth aligned closely with experimental results (≤3.84% deviation). The model enables damage tolerance assessment for large-scale welded structures operating in corrosive environments.

深海结构焊接接头的腐蚀疲劳裂纹扩展（CFCP）决定了其长期暴露在恶劣海洋环境中的结构完整性。为了解决这一问题，本研究通过建立由塑性应变能驱动的裂纹扩展速率模型，对18Ni（250）马氏体时效钢焊接接头中的CFCP进行了研究。制作4个试件，在模拟海水（3.5% NaCl溶液）中进行疲劳试验，量化应力比为0.1和0.3时裂纹扩展寿命。数字图像相关表征了裂纹尖端循环塑性区演化，揭示了应变/应力幅值和塑性应变能分布。分析了循环塑性区行为，推导了塑性应变能，为CFCP速率模型奠定了基础。裂纹扩展数值模拟与实验结果吻合较好（偏差≤3.84%）。该模型能够对腐蚀性环境下的大型焊接结构进行损伤容限评估。

引用次数: 0