International Journal of Fatigue最新文献_第5页

An energy-based physics–data fusion model for thermomechanical fatigue life prediction of directionally solidified superalloys 基于能量的定向凝固高温合金热-机械疲劳寿命预测物理-数据融合模型

IF 6.8 2区材料科学 Q1 ENGINEERING, MECHANICAL

International Journal of Fatigue

Pub Date : 2026-01-25 DOI: 10.1016/j.ijfatigue.2026.109521

Jundong Wang , Yuanmin Tu , Song Wu , Pengfei He , Zhixun Wen

This study investigates the thermomechanical fatigue (TMF) behaviour and life prediction of directionally solidified nickel-based superalloys under different mechanical stress levels. TMF tests were first performed to obtain cyclic stress–strain responses and fatigue lives, and the associated fracture surfaces and microstructural evolution were characterised to identify the dominant damage and failure mechanisms at different stages. On this basis, a thermo-mechanically coupled TMF constitutive model incorporating anisotropic yielding and damage evolution was established. The classical Zamrik energy model was subsequently modified by embedding a nonlinear damage evolution law into the energy framework, introducing the viscoplastic energy dissipated per cycle as the driving variable, and explicitly accounting for the effects of phase angle and temperature, thereby yielding an energy-based TMF life-prediction relation. In parallel, a Transformer–LSTM network was constructed to learn a nonlinear mapping from multivariate time-series data to life-related features. Building on these developments, an energy-driven physics–data fusion life-prediction approach was proposed, in which the energy parameter predicted by the data-driven model is supplied to the modified Zamrik model for TMF life assessment. The results show that, under various loading conditions, most lives predicted by the fusion model fall within a two-fold dispersion band about the experimental data, with a generally conservative bias. The proposed approach combines high prediction accuracy with clear physical interpretability and provides a promising tool for TMF life evaluation and engineering design of nickel-based superalloy components.

研究了定向凝固镍基高温合金在不同机械应力水平下的热疲劳行为和寿命预测。首先进行TMF试验以获得循环应力-应变响应和疲劳寿命，并对相关断口表面和微观组织演变进行表征，以确定不同阶段的主要损伤和破坏机制。在此基础上，建立了考虑各向异性屈服和损伤演化的热-力耦合TMF本构模型。随后，对经典的Zamrik能量模型进行修正，将非线性损伤演化规律嵌入能量框架，引入每循环耗散的粘塑性能量作为驱动变量，并明确考虑相角和温度的影响，从而得到基于能量的TMF寿命预测关系。同时，构建了Transformer-LSTM网络，学习多变量时间序列数据到生命相关特征的非线性映射。在此基础上，提出了一种能量驱动的物理-数据融合寿命预测方法，将数据驱动模型预测的能量参数提供给改进的Zamrik模型，用于TMF寿命评估。结果表明，在不同的载荷条件下，核聚变模型预测的寿命与实验数据在两倍频散范围内，具有普遍的保守偏差。该方法具有较高的预测精度和清晰的物理可解释性，为镍基高温合金部件的TMF寿命评估和工程设计提供了一种有前景的工具。

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引用次数: 0

Redefining stress triaxiality for ultra-low cycle fatigue of structural steels 结构钢超低周疲劳应力三轴性的重新定义

IF 6.8 2区材料科学 Q1 ENGINEERING, MECHANICAL

International Journal of Fatigue

Pub Date : 2026-01-25 DOI: 10.1016/j.ijfatigue.2026.109520

Qun He , Michael C.H. Yam , Xue-Mei Lin , H.C. Ho , Kwok-Fai Chung

Stress triaxiality has been a cornerstone parameter for describing void growth and ductile fracture in metals for more than 60 years. Its classical definition, derived from

J_{2}

plasticity without accounting for backstress, becomes inadequate in ultra-low cycle fatigue conditions, where backstress evolution and load reversals significantly alter the stress state. In such cases, the conventional definition of stress triaxiality may even lead to singularities when the second invariant of deviatoric stress, i.e.,

J_{2}

, approaches zero. This study revisits the classical void growth problem and demonstrates that the definition of stress triaxiality is inherently dependent on the adopted plasticity model. Specifically, once backstress is included in cyclic plasticity, it must also be accounted for in the definition of stress triaxiality to maintain consistency. In this way, a new definition of stress triaxiality incorporating the effect of backstress is proposed, providing a physically meaningful measure of stress triaxiality under cyclic loading. The new definition is analytically derived and validated through ultra-low cycle fatigue (ULCF) experiments of high-strength steel Q690, supported by finite element simulations. Results show that the proposed definition reliably captures the stress state associated with void growth and accurately predicts ULCF crack initiation life, overcoming the limitations of the classical definition. These findings establish, for the first time, a consistent theoretical and experimental basis for extending void-based fracture models to cyclic loading, with direct implications for assessing the seismic safety of steel structures.

60多年来，应力三轴性一直是描述金属中空洞生长和韧性断裂的基础参数。它的经典定义是从J2塑性推导而来，没有考虑回应力，在超低周疲劳条件下变得不充分，在超低周疲劳条件下，回应力演化和载荷反转会显著改变应力状态。在这种情况下，当偏应力的第二个不变量J2趋近于零时，应力三轴性的传统定义甚至可能导致奇点。该研究回顾了经典的空洞生长问题，并证明应力三轴性的定义本质上依赖于所采用的塑性模型。具体来说，一旦回应力被纳入循环塑性，它也必须在应力三轴性的定义中考虑，以保持一致性。通过这种方式，提出了包含背应力影响的应力三轴性的新定义，为循环加载下的应力三轴性提供了一种物理上有意义的测量方法。通过高强度钢Q690的超低周疲劳试验，结合有限元模拟，对新定义进行了解析推导和验证。结果表明，该定义可靠地捕捉了与孔洞扩展相关的应力状态，并准确地预测了ULCF裂纹起裂寿命，克服了经典定义的局限性。这些发现首次为将基于孔洞的断裂模型扩展到循环荷载建立了一致的理论和实验基础，对评估钢结构的抗震安全性具有直接意义。

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引用次数: 0

Fatigue resistance of stainless steel bolts under tension 不锈钢螺栓在拉力作用下的抗疲劳性能

IF 6.8 2区材料科学 Q1 ENGINEERING, MECHANICAL

International Journal of Fatigue

Pub Date : 2026-01-23 DOI: 10.1016/j.ijfatigue.2026.109515

Lukas Ehrhardt, Natalie Stranghöner

Bolted connections made of stainless steel are increasingly used in cyclic loading applications. The design rules according to the current version of the first generation of EN 1993-1-9 were historically developed for carbon steel bolts and apply equally to stainless steel bolts, although the material properties of carbon and stainless steel bolts differ significantly. Furthermore, the fatigue resistance of stainless steel bolts is almost unknown. In the draft of the second generation of EN 1993-1-9, FprEN 1993-1-9, design rules for stainless steel bolts are not specified anymore.

For this reason, fatigue tests under constant amplitude loading under tension were conducted with bolts M16, M20, M24 and M36 according to EN ISO 4014/4017 made of austenitic stainless steel (A2 and A4) and austenitic-ferritic (duplex) stainless steel (D4, D6 and D8) with property classes 70, 80 and 100. In total, 175 fatigue tests under constant amplitude loading under tension were performed in accordance with DIN 969.

The fatigue tests showed that the investigated stainless steel bolts achieve higher fatigue resistances than specified by the detail category according to EN 1993-1-9, so that the specified fatigue resistance is conservative. Based on the results, modifications of the detail categories for stainless steel bolts and rods are proposed, which allow a more economical design. The results of this investigation have already been proposed for an early amendment to FprEN 1993-1-9. This paper provides background information of the proposed modifications.

不锈钢螺栓连接越来越多地用于循环加载应用。根据第一代EN 1993-1-9当前版本的设计规则，历史上是为碳钢螺栓开发的，同样适用于不锈钢螺栓，尽管碳螺栓和不锈钢螺栓的材料性能有很大不同。此外，不锈钢螺栓的抗疲劳性能几乎是未知的。在第二代en1993 -1-9、FprEN 1993-1-9的草案中，不再规定不锈钢螺栓的设计规则。为此，根据EN ISO 4014/4017标准，用性能等级为70、80和100的奥氏体不锈钢（A2和A4）和奥氏体-铁素体（双相）不锈钢（D4、D6和D8）制作的螺栓M16、M20、M24和M36进行了恒幅载荷下的拉伸疲劳试验。根据DIN 969，总共进行了175次恒幅载荷下的拉伸疲劳试验。疲劳试验表明，所研究的不锈钢螺栓的抗疲劳性能高于en1993 -1-9细部分类规定的抗疲劳性能，因此规定的抗疲劳性能是保守的。在此基础上，提出了对不锈钢螺栓和杆的细部分类进行修改的建议，使设计更加经济。这项调查的结果已被提议尽早修订FprEN 1993-1-9。本文提供了拟议修改的背景资料。

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引用次数: 0

Bayesian model updating and model validation for fatigue life prediction of additively manufactured aluminum alloys 增材制造铝合金疲劳寿命预测的贝叶斯模型更新与模型验证

IF 6.8 2区材料科学 Q1 ENGINEERING, MECHANICAL

International Journal of Fatigue

Pub Date : 2026-01-23 DOI: 10.1016/j.ijfatigue.2026.109501

Zhanhua Liang , Jingwen Song , Feifan Li , Xianmin Chen , Jihong Zhu , Weihong Zhang

Fatigue life prediction for additively manufactured aluminum alloys is challenging due to limited data and significant material scatter. To address this, this study proposes a Bayesian uncertainty quantification framework for probabilistic prediction and model selection. Fatigue experiments were conducted on Laser Powder Bed Fusion (LPBF) AlSi10Mg specimens under two build directions. Bayesian inference was employed to update the parameters of four candidate models, characterizing data scarcity in the form of prediction uncertainty. U-pooling and Model Evidence metrics were then utilized to quantitatively evaluate model performance. The proposed framework effectively generated 95% confidence intervals that encapsulate most of the experimental data. Results indicate that specimens loaded perpendicular to the build direction (H-direction) exhibit superior fatigue resistance compared to those loaded parallel to it (S-direction). Quantitative validation identifies the Smith-Watson-Topper model and the Morrow model as the optimal predictors for the two directions. This work provides a reliable tool for fatigue assessment under data-scarce conditions.

由于数据有限和材料分散严重，增材制造铝合金的疲劳寿命预测具有挑战性。为了解决这个问题，本研究提出了一个用于概率预测和模型选择的贝叶斯不确定性量化框架。对激光粉末床熔合（LPBF） AlSi10Mg试样在两种构建方向下进行了疲劳试验。采用贝叶斯推理更新四个候选模型的参数，以预测不确定性的形式表征数据稀缺性。然后使用u池和模型证据度量来定量评估模型性能。提出的框架有效地生成了95%的置信区间，封装了大多数实验数据。结果表明，竖向加载（h方向）比平行加载（s方向）具有更好的抗疲劳性能。定量验证表明Smith-Watson-Topper模型和Morrow模型是两个方向的最佳预测因子。这项工作为数据稀缺条件下的疲劳评估提供了可靠的工具。

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引用次数: 0

Vision-driven and Bayesian-enhanced YOLO-PINN hybrid framework for crack propagation and fatigue life prediction 视觉驱动和贝叶斯增强的ylo - pinn混合框架用于裂纹扩展和疲劳寿命预测

IF 6.8 2区材料科学 Q1 ENGINEERING, MECHANICAL

International Journal of Fatigue

Pub Date : 2026-01-22 DOI: 10.1016/j.ijfatigue.2026.109511

Zhizhuo Zhang , Mengchuang Zhang , Yan Li , Enrico Zappino , Zhiping Yin

Accurate detection and prediction of crack propagation are critical for maintaining the integrity and extending the service life of aerospace structures. We present a novel hybrid framework that integrates deep learning-based computer vision with physics-informed modeling to improve crack-growth forecasting. First, an enhanced You Only Look Once (YOLO) object-detection and segmentation network precisely extracts crack morphology from inspection images. These measurements feed into physics-informed neural network (PINN) that embeds the governing fracture mechanics equations to predict temporal growth trajectories. To maximize predictive accuracy, a Bayesian correlation scheme iteratively selects and refines the training set, ensuring inclusion of the most informative imaging samples. This feedback loop continuously enhances the model’s adaptability and reliability. Validation on benchmark datasets demonstrates that our hybrid approach significantly outperforms purely data-driven or purely physics-based methods, offering robust, real-time structural health monitoring. The proposed methodology provides a novel approach for predictive maintenance and lifecycle management of critical aerospace components.

裂纹扩展的准确检测和预测对于保持航天结构的完整性和延长其使用寿命至关重要。我们提出了一种新的混合框架，将基于深度学习的计算机视觉与物理信息建模相结合，以改进裂缝增长预测。首先，一个增强的You Only Look Once （YOLO）目标检测和分割网络精确地从检测图像中提取裂纹形态。这些测量结果输入到物理信息神经网络（PINN）中，该网络嵌入了控制断裂力学方程，以预测时间生长轨迹。为了最大限度地提高预测精度，贝叶斯相关方案迭代地选择和改进训练集，确保包含最具信息量的成像样本。这种反馈回路不断增强了模型的适应性和可靠性。在基准数据集上的验证表明，我们的混合方法明显优于纯粹的数据驱动或纯粹基于物理的方法，提供强大的实时结构健康监测。该方法为航空航天关键部件的预测性维护和生命周期管理提供了一种新的方法。

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引用次数: 0

Microstructural origins for the simultaneously enhanced high-cycle fatigue performance and fatigue crack growth resistance of a carbide-free bainite steel 无碳化物贝氏体钢同时提高高周疲劳性能和抗疲劳裂纹扩展性能的组织根源

IF 6.8 2区材料科学 Q1 ENGINEERING, MECHANICAL

International Journal of Fatigue

Pub Date : 2026-01-22 DOI: 10.1016/j.ijfatigue.2026.109513

Tianyu Zhang , Yu Wang , Zhanqing Yin , Xiaoming Liu , Chenchong Wang , Lingyu Wang , Chi Zhang , Wei Xu

Carbide-free bainite (CFB) steel, consisting of bainitic laths and metastable retained austenite (RA), offers excellent static properties and fatigue resistance, making it a potential replacement for conventional axle steels. However, the relationships among its microstructure, fatigue life under various stresses, and fatigue crack growth (FCG) behavior remain unclear. This study designed two CFB axle steels, AT350 and AT300, by austempering at 350 °C or 300 °C followed by low-temperature tempering, producing different bainitic lath sizes and RA stabilities. Their mechanical properties, high-cycle fatigue (HCF) performance, and FCG behavior were systematically investigated. The AT300 sample featured finer bainite laths (average thickness: 231 nm) and higher RA stability than that of the AT350 sample, due to prior austenite grain segmentation by primary martensite. Consequently, AT300 achieved higher tensile strength (1575 MPa) and HCF strength (760 MPa, fatigue limit at 10⁷ cycles). Under low-stress fatigue, the AT300 sample exhibited longer life and slower crack growth than the AT350 sample. Under high-stress fatigue, however, the fatigue lives of the AT350 and AT300 samples were nearly equivalent, as AT350′s greater ductility and secondary cracking compensated for its lower strength. In the FCG regime, AT300 showed a wider resistance plateau and a lower Paris exponent, indicating superior crack growth resistance. This enhancement arises from fine bainitic laths deflecting cracks and stable RA reducing martensitic transformation at the crack tip, thereby avoiding brittle martensite channels and absorbing strain energy. These findings provide valuable theoretical and experimental guidance for designing axle steels with superior fatigue resistance.

无碳化物贝氏体（CFB）钢由贝氏体板条和亚稳残余奥氏体（RA）组成，具有优异的静态性能和抗疲劳性能，是传统车轴钢的潜在替代品。然而，其显微组织、不同应力下的疲劳寿命和疲劳裂纹扩展（FCG）行为之间的关系尚不清楚。本研究设计了两种循环流化床车轴钢AT350和AT300，分别在350°C和300°C等温回火，然后再进行低温回火，产生了不同的贝氏体板条尺寸和RA稳定性。系统地研究了它们的力学性能、高周疲劳（HCF）性能和FCG行为。与AT350相比，AT300样品具有更细的贝氏体板条（平均厚度为231 nm）和更高的RA稳定性，这是由于初生马氏体对奥氏体晶粒进行了预先分割。因此，AT300获得了更高的抗拉强度（1575 MPa）和HCF强度（760 MPa， 107次循环的疲劳极限）。在低应力疲劳下，AT300试样比AT350试样具有更长的寿命和更慢的裂纹扩展。然而，在高应力疲劳下，AT350和AT300样品的疲劳寿命几乎相等，因为AT350的高延展性和二次开裂弥补了其较低的强度。在FCG状态下，AT300表现出更宽的阻力平台和更低的Paris指数，表明其具有更强的抗裂纹扩展能力。这种增强是由于细小的贝氏体板条偏转裂纹和稳定的RA减少了裂纹尖端的马氏体转变，从而避免了脆性马氏体通道并吸收了应变能。这些研究结果为设计具有优良抗疲劳性能的车轴钢提供了有价值的理论和实验指导。

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引用次数: 0

Low-cycle fatigue performance and porosity evolution in spray-formed 7055 Al-alloy 喷射成形7055铝合金的低周疲劳性能及孔隙率演变

IF 6.8 2区材料科学 Q1 ENGINEERING, MECHANICAL

International Journal of Fatigue

Pub Date : 2026-01-22 DOI: 10.1016/j.ijfatigue.2026.109514

Weichang Wei , Chenyang Zhang , Yapeng Huang , Xia He , Yong Zhang , Guang Li , Yanjin Xu , Baoshuai Han , Cai Hu , Lingying Ye

The effects of pore characteristics and evolution on the fatigue performance of spray-formed 7055 aluminum alloy were investigated using synchrotron X-ray computed tomography (CT), electron backscatter diffraction (EBSD), scanning electron microscopy (SEM), and transmission electron microscopy (TEM). The results demonstrate that pore characteristics and their evolution during cyclic loading directly govern the fatigue performance. As the extrusion ratio increased from 7 to 48, the size and number density of pores decreased significantly, which was accompanied by a progressive improvement in low-cycle fatigue life. During fatigue cycling, severe local plastic deformation occurred around pores sized 10–20 μm, causing substantial pore growth and promoting rapid crack initiation. For pores sized 5–10 μm, the local plastic deformation was less pronounced, resulting in delayed crack initiation and extended fatigue life. Pores smaller than 5 μm underwent negligible plastic deformation and thus had a minimal impact on fatigue performance. Moreover, pores accelerated fatigue crack propagation by providing preferential paths for rapid crack growth.

采用同步x射线计算机断层扫描（CT）、电子背散射衍射（EBSD）、扫描电子显微镜（SEM）和透射电子显微镜（TEM）研究了孔隙特征及其演化对喷射成形7055铝合金疲劳性能的影响。结果表明，孔隙特征及其在循环加载过程中的演变直接决定了材料的疲劳性能。随着挤压比从7增加到48，孔隙尺寸和数量密度显著减小，低周疲劳寿命逐步提高。在疲劳循环过程中，孔径为10 ~ 20 μm的孔隙周围发生了严重的局部塑性变形，孔隙扩展迅速，裂纹萌生迅速。当孔隙尺寸为5 ~ 10 μm时，局部塑性变形不明显，裂纹起裂延迟，疲劳寿命延长。小于5 μm的孔隙塑性变形可以忽略不计，因此对疲劳性能的影响最小。此外，孔隙通过为裂纹快速扩展提供优先路径来加速疲劳裂纹扩展。

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引用次数: 0

Mechanistic insight and universal life prediction of strain rate-dependent fatigue in nickel-based superalloy at elevated temperature 镍基高温合金高温应变速率相关疲劳的机理及通用寿命预测

IF 6.8 2区材料科学 Q1 ENGINEERING, MECHANICAL

International Journal of Fatigue

Pub Date : 2026-01-21 DOI: 10.1016/j.ijfatigue.2026.109512

Hao-Qi Fan , Kai-Shang Li , Ning Yao , Wen-Rui Nie , Run-Zi Wang , Ti-Wen Lu , Lu Cheng , Xiu-Fang Gong , Xian-Cheng Zhang , Shan-Tung Tu

Start-up and shut-down transients in turbomachinery impose varying strain rates that affect the in-service life of high-temperature components. However, the quantitative role of strain rate sensitivity in high-temperature fatigue of nickel-based superalloys remains inadequately reflected in damage mechanism and life prediction. In this study, fully-reversed strain-controlled low cycle fatigue (LCF) tests were performed at 650 ℃ over a wide range of strain rates from 5 × 10⁻⁵ to 1 × 10⁻² s⁻¹. The experimental results reveal the existence of a threshold strain-rate range for nickel-based superalloy IN718. When the strain rate exceeds this threshold, the fatigue life remains nearly constant with increasing strain rate. The cracking behavior is dominated by the transgranular-intergranular mixed mode. In contrast, at strain rates below this threshold, the fatigue life decreases rapidly due to the time available for oxidation- and creep-assisted damage. Based on these observations, a modified energy-based model incorporating the strain rate sensitivity was proposed using tensile-derived plastic strain energy density, achieving a prediction accuracy of 97% within a ±2 error band. These findings provide an effective strategy for enhancing the service reliability of high-temperature rotating components.

涡轮机械的启动和关闭瞬态产生不同的应变速率，从而影响高温部件的使用寿命。然而，应变率敏感性在镍基高温合金高温疲劳中的定量作用在损伤机理和寿命预测中仍未得到充分体现。在这项研究中，在650℃下，在5 × 10−5到1 × 10−2 s−1的应变速率范围内进行了完全反向应变控制低周疲劳（LCF）试验。实验结果表明，镍基高温合金IN718存在一个阈应变速率范围。当应变速率超过该阈值时，随着应变速率的增加，疲劳寿命基本保持不变。裂纹行为以穿晶-晶间混合模式为主。相反，当应变率低于该阈值时，由于氧化和蠕变辅助损伤的可用时间，疲劳寿命迅速下降。基于这些观察结果，提出了一种改进的基于能量的模型，结合应变率敏感性，使用拉伸导出的塑性应变能密度，在±2的误差范围内实现了97%的预测精度。这些研究结果为提高高温旋转部件的使用可靠性提供了有效的策略。

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引用次数: 0

Effect of distinct ferrite structures on the crack propagation behavior in a Si-enriched ferritic/martensitic (F/M) steel under low-cycle fatigue (LCF) at 600 ℃ 不同铁素体组织对富si铁素体/马氏体（F/M）钢600℃低周疲劳裂纹扩展行为的影响

IF 6.8 2区材料科学 Q1 ENGINEERING, MECHANICAL

International Journal of Fatigue

Pub Date : 2026-01-20 DOI: 10.1016/j.ijfatigue.2026.109517

Jun Zhang , Xiaoxin Zhang , Hao Ren , Decang Zhang , Yingxue Chen , Feifei Zhang , Xinhao Zhang , Qingzhi Yan

Advanced power plants demand steels with enhanced high-temperature low-cycle fatigue (LCF) performance. However, the insufficient understanding of ferrite’s role in crack propagation limits both optimization design and application of the novel Si-enriched ferritic/martensitic (F/M) steels. Hence, the crack propagation behavior during LCF was investigated in steels with varied ferrite structures obtained through two distinct treatments: normalizing & tempering process (NT) and hot rolling & tempering process (HR). The ferrite for NT is “clearer” with few and large sub-grains, whereas, for HR, the ferrite contains high density of small sub-grains. These sub-grains with slightly different orientation effectively deflect the crack propagation path. Moreover, hot rolling produced a pronounced texture characterized by a large misorientation between the crack plane and the {100} cleavage plane, thereby increasing the energy required for crack propagation. The sub-grain structure together with the strong texture indicates a higher resistance to crack propagation for HR. However, the notably higher ferrite fraction for HR results in a lower fatigue life, as the suboptimal strength ultimately leads to a premature onset of stage III with sharply decreasing stress, which limits the period of stable crack propagation, thereby, inducing an early failure. This excessive ferrite was formed due to the temperature drop during hot rolling, which shifted the calculated equilibrium ferrite from <5 % to nearly 45 %. Overall, these results highlight the importance of ferrite refinement and fraction control in optimizing the fatigue resistance of Si-enriched F/M steels. Guided by this insight, potential processing strategies are proposed for future optimization.

先进的电厂要求钢具有增强的高温低周疲劳性能。然而，对铁素体在裂纹扩展中的作用认识不足，限制了新型富硅铁素体/马氏体（F/M）钢的优化设计和应用。因此，通过正火回火（NT）和热轧回火（HR）两种不同的处理方法，研究了不同铁素体组织的钢在LCF过程中的裂纹扩展行为。NT的铁素体“更清晰”，亚晶粒少而大，而HR的铁素体则含有高密度的小亚晶粒。这些取向稍有不同的亚晶有效地偏转了裂纹扩展路径。此外，热轧产生了明显的织构，其特征是裂纹面与{100}解理面之间存在较大的错向，从而增加了裂纹扩展所需的能量。亚晶组织和强织构表明，HR具有较高的抗裂纹扩展能力。然而，较高的铁素体分数会导致较低的疲劳寿命，因为次优强度最终会导致III阶段过早开始，应力急剧下降，从而限制了稳定裂纹扩展的时间，从而导致早期失效。这种过量的铁素体是由于热轧过程中的温度下降而形成的，它使计算的平衡铁素体从<； 5%移动到近45%。总之，这些结果突出了铁素体细化和分数控制对优化富硅F/M钢的抗疲劳性能的重要性。在这一见解的指导下，提出了未来优化的潜在处理策略。

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引用次数: 0

Effect of fatigue-initiating defect area measurement on defect size distributions and fatigue assessment of ductile cast iron 疲劳启动缺陷面积测量对球墨铸铁缺陷尺寸分布及疲劳评定的影响

IF 6.8 2区材料科学 Q1 ENGINEERING, MECHANICAL

International Journal of Fatigue

Pub Date : 2026-01-19 DOI: 10.1016/j.ijfatigue.2026.109499

Max Ahlqvist , Viktor Norman , Daniel Leidermark

Numerous methods have been suggested to quantify fatigue-initiating defect size on fracture surfaces, the most prevalent are based on the Murakami–Endo

\sqrt{a r e a}

-parameter. However, there is an ambiguity in how to systemically determine defect areas. For instance, in literature on high-cycle fatigue of ductile cast irons the several different methods have been suggested: (i) the traced contour, (ii) the convex hull, (iii) the minimum circumscribed circle, and (iv) the minimum bounding rectangle. This work focuses on comparing and evaluating these methods by assessing the fatigue-initiating defect area distributions, and the influence on fatigue assessment using the

\sqrt{a r e a}

-parameter. To this end, very high cycle fatigue data on ductile cast irons with different microstructures is used, where complex shaped defects are the root-cause for fatigue failures. It is shown that there is a significant difference in the area distributions, originating from the applied area measurement method. In addition, to enable and include fatigue assessment of high strength ausferritic ductile irons, two improved Murakami–Endo type models are proposed, which show satisfactory prediction capabilities over a wide range of ductile cast iron microstructures. To further evaluate the different area measurement methods, the suggested models are validated against ductile cast iron high-cycle fatigue data from literature having artificial defects and notches. Finally, it is concluded that the traced contour defect measurement method yields the best agreement between artificial and natural defects, and overall, the least prediction errors.

人们提出了许多方法来量化断口表面的疲劳缺陷尺寸，最常用的是基于Murakami-Endo区域参数。然而，在如何系统地确定缺陷区域方面存在歧义。例如，在关于球墨铸铁高周疲劳的文献中，提出了几种不同的方法：(i)追踪轮廓，（ii）凸壳，（iii）最小外缘圆，（iv）最小边界矩形。本文通过评估疲劳启动缺陷的面积分布，以及使用面积参数对疲劳评估的影响，对这些方法进行了比较和评价。为此，使用了具有不同显微组织的球墨铸铁的高周疲劳数据，其中复杂形状的缺陷是疲劳失效的根本原因。结果表明，由于采用的面积测量方法不同，区域分布存在显著差异。此外，为了对高强度奥氏体球墨铸铁进行疲劳评估，提出了两种改进的Murakami-Endo模型，这两种模型在广泛的球墨铸铁显微组织范围内显示出令人满意的预测能力。为了进一步评估不同的面积测量方法，建议的模型与文献中含有人工缺陷和缺口的球墨铸铁高周疲劳数据进行了验证。最后，得出了跟踪轮廓缺陷测量方法在人工缺陷和自然缺陷之间的一致性最好，总体上预测误差最小的结论。

{"title":"Effect of fatigue-initiating defect area measurement on defect size distributions and fatigue assessment of ductile cast iron","authors":"Max Ahlqvist , Viktor Norman , Daniel Leidermark","doi":"10.1016/j.ijfatigue.2026.109499","DOIUrl":"10.1016/j.ijfatigue.2026.109499","url":null,"abstract":"<div><div>Numerous methods have been suggested to quantify fatigue-initiating defect size on fracture surfaces, the most prevalent are based on the Murakami–Endo <span><math><msqrt><mrow><mi>a</mi><mi>r</mi><mi>e</mi><mi>a</mi></mrow></msqrt></math></span>-parameter. However, there is an ambiguity in how to systemically determine defect areas. For instance, in literature on high-cycle fatigue of ductile cast irons the several different methods have been suggested: (i) the traced contour, (ii) the convex hull, (iii) the minimum circumscribed circle, and (iv) the minimum bounding rectangle. This work focuses on comparing and evaluating these methods by assessing the fatigue-initiating defect area distributions, and the influence on fatigue assessment using the <span><math><msqrt><mrow><mi>a</mi><mi>r</mi><mi>e</mi><mi>a</mi></mrow></msqrt></math></span>-parameter. To this end, very high cycle fatigue data on ductile cast irons with different microstructures is used, where complex shaped defects are the root-cause for fatigue failures. It is shown that there is a significant difference in the area distributions, originating from the applied area measurement method. In addition, to enable and include fatigue assessment of high strength ausferritic ductile irons, two improved Murakami–Endo type models are proposed, which show satisfactory prediction capabilities over a wide range of ductile cast iron microstructures. To further evaluate the different area measurement methods, the suggested models are validated against ductile cast iron high-cycle fatigue data from literature having artificial defects and notches. Finally, it is concluded that the traced contour defect measurement method yields the best agreement between artificial and natural defects, and overall, the least prediction errors.</div></div>","PeriodicalId":14112,"journal":{"name":"International Journal of Fatigue","volume":"207 ","pages":"Article 109499"},"PeriodicalIF":6.8,"publicationDate":"2026-01-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146000570","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

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