International Journal of Fatigue最新文献_第7页

Data driven topology optimization of AM parts accounting for process-affected fatigue performance: Application to automotive and aerospace components 考虑工艺影响疲劳性能的增材制造零件的数据驱动拓扑优化：在汽车和航空航天部件上的应用

IF 6.8 2区材料科学 Q1 ENGINEERING, MECHANICAL

International Journal of Fatigue

Pub Date : 2026-05-01 Epub Date: 2026-01-07 DOI: 10.1016/j.ijfatigue.2026.109481

Alessio Centola , Alberto Ciampaglia , Carlo Boursier Niutta , Filippo Berto , Davide Salvatore Paolino , Andrea Tridello

The present paper presents two novel data-driven topology optimization (TO) procedures to design lighter additively manufactured (AM) fatigue resistant components. The first TO method is driven by a probabilistic machine learning (ML) algorithm based on a Bayesian Neural Network (BNN), trained on fatigue data from the literature to assess probabilistic stress-life (PSN) curves. These curves are used to predict the allowable design stress for TO and are predicted directly from AM process parameters, the risk volume, and thermal and surface treatments. The second TO design procedure is instead driven by another BNN, trained to predict the maximum critical defect size from the process parameters. The TO limit stress is computed from the predicted critical defect and the threshold stress intensity factor K_th. After the TO, the critical stress intensity factor K_I in the component is computed and compared against K_th, to assess the effectiveness of this design procedure. These two frameworks are applied to the design of an SS316L automotive suspension lower control arm and a Ti6Al4V aerospace bracket, respectively. With the following framework, the limit stress calculation does not require specifically designed experimental campaigns and prototyping, as previously sparse experimental knowledge can be embedded in a powerful design tool, which allows for preventing fatigue failures, while accounting directly for the influence of the AM process parameters.

本文提出了两种新的数据驱动拓扑优化（TO）方法来设计更轻的增材制造（AM）抗疲劳部件。第一种TO方法由基于贝叶斯神经网络（BNN）的概率机器学习（ML）算法驱动，该算法根据文献中的疲劳数据进行训练，以评估概率应力寿命（PSN）曲线。这些曲线用于预测to的允许设计应力，并直接从增材制造工艺参数、风险体积、热处理和表面处理中进行预测。第二个TO设计程序由另一个BNN驱动，该BNN经过训练，可以从工艺参数中预测最大临界缺陷尺寸。根据预测的临界缺陷和阈值应力强度因子Kth计算极限应力。在TO之后，计算组件中的临界应力强度因子KI并与Kth进行比较，以评估该设计过程的有效性。这两种框架分别应用于SS316L汽车悬架下控制臂和Ti6Al4V航空航天支架的设计。有了下面的框架，极限应力计算不需要专门设计的实验活动和原型，因为以前稀疏的实验知识可以嵌入到一个强大的设计工具中，这可以防止疲劳失效，同时直接考虑到增材制造工艺参数的影响。

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引用次数: 0

Fully-lamellar equiaxed structure mediated excellent high-temperature fatigue crack growth resistance of Ti-48Al-2Cr-2Nb alloy fabricated via twin-wire directed energy deposition-arc process 双线定向能沉积-电弧工艺制备的Ti-48Al-2Cr-2Nb合金具有优异的耐高温疲劳裂纹扩展性能

IF 6.8 2区材料科学 Q1 ENGINEERING, MECHANICAL

International Journal of Fatigue

Pub Date : 2026-05-01 Epub Date: 2026-01-09 DOI: 10.1016/j.ijfatigue.2026.109488

Danqi Zhang , Chen Shen , Lin Wang , Wenlu Zhou , Ting Zhang , Ying Li , Yuelong Zhang , Fang Li , Jianwen Xin , Kanglong Wu , Gang Ruan , Xueming Hua

As a critical milestone of twin-wire directed energy deposition-arc (TW-DED-arc) technology, we present the first report on the excellent fatigue crack growth (FCG) performance of a Ti–48Al–2Cr–2Nb (TiAl-4822) alloy with a refined fully-lamellar microstructure. FCG tests conducted on standard compact tension specimens from two orthogonal directions under cyclic loading at 650 °C (R = 0.1) demonstrated a high fatigue threshold (∼8.0 MPa·m^1/2) and low crack propagation rates compared to conventionally manufactured counterparts. The isotropic microstructure rendered crack resistance insensitive to deposition direction. In-situ tensile analysis under electron back scattered diffraction revealed that the enhanced performance originates from refined lamellar spacing, which promoted super-dislocation (SD) activity. Tortuous crack paths formed by mortise–tenon interlocks in inter-lamellar crack and zigzag trans-lamellar cracking, which effectively deflected cracks and dissipate energy. Furthermore, high volume fraction of γ-phase (89.4%) with low stacking fault energy facilitated dislocation dissociation and deformation twinning (DT). These mechanisms collectively enhanced stress relaxation through twin interactions and SD immobilization, significantly improving crack resistance. This study not only reports a previously undocumented property profile but also underscores the technological potential of TW-DED-arc for manufacturing high-performance titanium aluminide components.

作为双线定向能沉积电弧（tw - ed -arc）技术的一个重要里程碑，我们首次报道了一种具有精致的全层状组织的Ti-48Al-2Cr-2Nb （TiAl-4822）合金的优异疲劳裂纹扩展（FCG）性能。在650°C （R = 0.1）循环加载下，对两个正交方向的标准致密拉伸试样进行的FCG试验表明，与常规制造的试件相比，其疲劳阈值高（~ 8.0 MPa·m1/2），裂纹扩展率低。各向同性组织使得抗裂性能对沉积方向不敏感。电子背散射衍射原位拉伸分析表明，晶片间距的细化促进了超位错（SD）活性的提高。片间裂纹和片间裂纹中榫卯互锁形成的弯曲裂纹路径，有效地偏转了裂纹并耗散了能量。高体积分数γ-相（89.4%）和低层错能有利于位错解离和变形孪晶（DT）。这些机制通过孪生相互作用和SD固定共同增强应力松弛，显著提高抗裂性。这项研究不仅报告了以前未记载的性能概况，而且强调了tw - ed电弧在制造高性能钛铝组件方面的技术潜力。

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引用次数: 0

Process gas influence on Very-High-Cycle fatigue response of Inconel 718 fabricated by laser powder bed fusion 工艺气体对激光粉末床熔合Inconel 718超高周疲劳响应的影响

IF 6.8 2区材料科学 Q1 ENGINEERING, MECHANICAL

International Journal of Fatigue

Pub Date : 2026-05-01 Epub Date: 2025-12-29 DOI: 10.1016/j.ijfatigue.2025.109460

Ali Rauf , Indrajit Nandi , Kim Vanmeensel , Reza Talemi

Inconel 718 (IN-718) is a precipitation-strengthened nickel-based superalloy that is widely explored for its applicability in fatigue-critical applications when fabricated using additive manufacturing (AM) at an industrial scale. Among the various factors influencing its performance, the choice of shielding gas during laser powder bed fusion (L-PBF) plays a crucial yet often overlooked role in determining the material’s microstructure and mechanical behaviour. This study investigates the critical influence of shielding gases like argon and nitrogen on the microstructure, defect distribution and the very high cycle fatigue (VHCF) durability of heat-treated L-PBF fabricated IN-718. Defect quantification was undertaken using a combination of optical microscopy, Archimedes density measurements, X-ray computed tomography (XCT), revealing higher defect contents in samples processed under nitrogen shielding. Microstructural analysis through scanning electron microscopy (SEM), electron backscatter diffraction (EBSD), and energy-dispersive X-ray spectroscopy (EDS) revealed pronounced variations in grain morphology and inclusion content between the two gas environments. VHCF tests were performed under fully reversed, uniaxial, stress-controlled loading at 20 kHz using dog-bone specimens with larger risk volumes to capture a conservative fatigue life assessment. Fatigue life distributions were analysed using a Weibull accelerated failure time model, revealing similar median lives but narrower scatter for argon-shielded specimens. Fractographic analysis revealed distinct crack-initiation mechanisms, microstructure driven initiation in argon-shielded specimens leaving facets at initiation sites versus defect-assisted initiation often involving inclusions along with pores and lack-of-fusion (LOF) defects in nitrogen-shielded counterparts. Although nitrogen shielding produced a refined microstructure, the elevated porosity and inclusion density-controlled crack initiation and degraded fatigue performance.

Inconel 718 （in -718）是一种沉淀强化镍基高温合金，在工业规模的增材制造（AM）制造中，因其在疲劳临界应用中的适用性而被广泛探索。在影响材料性能的诸多因素中，保护气体的选择对材料的微观结构和力学性能起着至关重要的作用，但往往被忽视。研究了氩气和氮气等保护气体对热处理后的L-PBF IN-718的组织、缺陷分布和高周疲劳耐久性的关键影响。使用光学显微镜、阿基米德密度测量、x射线计算机断层扫描（XCT）进行缺陷量化，发现在氮屏蔽下处理的样品中缺陷含量较高。通过扫描电镜（SEM）、电子背散射衍射（EBSD）和能量色散x射线能谱（EDS）对两种气体环境的微观结构进行分析，发现两种气体环境的晶粒形貌和夹杂物含量存在显著差异。VHCF测试在完全反向、单轴、应力控制的20 kHz载荷下进行，使用具有较大风险体积的狗骨样本进行保守疲劳寿命评估。使用Weibull加速失效时间模型分析疲劳寿命分布，显示氩气保护试样的中位数寿命相似，但分散范围更窄。断口分析揭示了不同的裂纹起裂机制，氩气保护试样的微观结构驱动起裂在起裂部位留下刻面，而氮保护试样的缺陷辅助起裂通常包括夹杂物、气孔和缺乏熔合（LOF）缺陷。虽然氮屏蔽产生了细化的微观组织，但孔隙率和夹杂物密度的升高控制了裂纹的萌生，降低了疲劳性能。

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引用次数: 0

Critical defect-driven fatigue evolution mechanism and life prediction of Ti6Al4V part built by laser powder bed fusion 激光粉末床熔合Ti6Al4V零件临界缺陷驱动疲劳演化机理及寿命预测

IF 6.8 2区材料科学 Q1 ENGINEERING, MECHANICAL

International Journal of Fatigue

Pub Date : 2026-05-01 Epub Date: 2025-12-30 DOI: 10.1016/j.ijfatigue.2025.109476

Jiasen Gu , Deqiao Xie , Xuwen Gu , Shuang Liu , Kai Zhou , Chen Jiao , Rong Jiang , Xinfeng Lv , Juan Hu , Zongjun Tian , Dongsheng Wang , Lida Shen

Fatigue life prediction of laser powder bed fusion (LPBF) components remains challenging because critical defects cannot be reliably identified before service, resulting in large scatter and limited applicability of existing methods. In this study, an integrated framework combining quasi in-situ X-ray computed tomography (XCT), finite element method (FEM), and machine learning (ML) was developed to rapidly screen critical defects and predict fatigue life prior to loading. The results revealed the early-stage evolution of critical defects during crack initiation, and a Murakami-Basquin model was established to quantitatively link defect features with fatigue life. Moreover, the FEM-driven ML approach achieved high-accuracy life prediction within a 1.5× error band, with

σ_{FEM}

identified as the dominant factor, followed by defect depth (

h

) and

\sqrt{area}

, in agreement with classical fatigue criteria. Demonstrated with Ti6Al4V, this work establishes a critical-defect-driven pathway for fatigue life prediction, providing a broadly applicable methodology for defect-sensitive design and life assessment of LPBF components.

激光粉末床熔合（LPBF）部件的疲劳寿命预测仍然具有挑战性，因为在使用前无法可靠地识别关键缺陷，导致现有方法的分散性大，适用性有限。在这项研究中，开发了一个结合准原位x射线计算机断层扫描（XCT）、有限元法（FEM）和机器学习（ML）的集成框架，以快速筛选关键缺陷并在加载前预测疲劳寿命。结果揭示了裂纹萌生过程中关键缺陷的早期演化过程，并建立了Murakami-Basquin模型，定量地将缺陷特征与疲劳寿命联系起来。以σFEM为主导因素，缺陷深度(h)和面积次之，在1.5×误差范围内实现了高精度的寿命预测，符合经典疲劳准则。以Ti6Al4V为例，这项工作建立了一个关键缺陷驱动的疲劳寿命预测路径，为缺陷敏感设计和LPBF部件的寿命评估提供了广泛适用的方法。

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引用次数: 0

Predicting the whole-life stress amplitude evolution of high-Mn TWIP steel under complex loading conditions using fatigue failure criteria and machine learning 基于疲劳失效准则和机器学习的高mn TWIP钢在复杂载荷条件下的全寿命应力幅值演化预测

IF 6.8 2区材料科学 Q1 ENGINEERING, MECHANICAL

International Journal of Fatigue

Pub Date : 2026-05-01 Epub Date: 2025-12-22 DOI: 10.1016/j.ijfatigue.2025.109449

Di Song , Jinze Pei , Ye Xiao , Ronghai Wu , Heng Li

Previous research on fatigue performance has primarily focused on fatigue life, with limited emphasis on the evolution of stress amplitude. However, stress amplitude is a critical parameter in strain-controlled fatigue failure analysis. The interaction of deformation mechanisms during cyclic loading complicates the evolution of stress amplitude, and this challenge is further amplified when considering the applicability of models across diverse loading conditions. This study employs both failure criteria-based and machine learning approaches to develop predictive models for the entire fatigue life stress amplitude evolution under varying loading orientations, pre-strains, temperatures, and strain amplitudes. The failure criteria-based model introduces a novel combined prediction framework of fatigue life and stress amplitude, enabling the prediction of four representative stress amplitudes: initial, maximum, half-life, and failure. The fatigue life prediction achieves an accuracy of 96.1 % within a 2 × error band, while stress amplitude predictions attain 96.4 % within a 1.2 × error band. The machine learning model, based on symbolic regression, utilizes these four amplitudes as training data to derive an interpretable formula for the entire evolution curve, achieving 99.7 % data within the 1.2 × error band. The overall curve exhibits a high R² of 0.95 and a mean absolute percentage error (MAPE) of 1.87 %, demonstrating robust predictive capability across diverse conditions.

以往对疲劳性能的研究主要集中在疲劳寿命上，对应力幅值的演化研究较少。而应力幅值是应变控制疲劳失效分析中的一个关键参数。循环加载过程中变形机制的相互作用使应力幅值的演化变得复杂，考虑到模型在不同加载条件下的适用性，这一挑战进一步放大。本研究采用基于失效准则的方法和机器学习方法，建立了在不同加载方向、预应变、温度和应变幅值下的整个疲劳寿命应力幅值演变的预测模型。基于失效准则的模型引入了一种新的疲劳寿命和应力幅值组合预测框架，能够预测4种具有代表性的应力幅值：初始、最大、半衰期和失效。疲劳寿命预测精度在2 ×误差范围内达到96.1%，应力幅值预测精度在1.2 ×误差范围内达到96.4%。机器学习模型基于符号回归，利用这四个幅值作为训练数据，推导出整个进化曲线的可解释公式，在1.2 ×误差范围内实现99.7%的数据。总体曲线的R2为0.95，平均绝对百分比误差（MAPE）为1.87%，显示出在不同条件下的稳健预测能力。

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引用次数: 0

Slow fatigue crack growth induced microstructure evolution far beyond the crack tip plastic zone in nickle-based superalloy 在镍基高温合金中，缓慢疲劳裂纹扩展导致的组织演化远远超出裂纹尖端塑性区

IF 6.8 2区材料科学 Q1 ENGINEERING, MECHANICAL

International Journal of Fatigue

Pub Date : 2026-05-01 Epub Date: 2025-12-08 DOI: 10.1016/j.ijfatigue.2025.109430

Jiafen Cao , Mengqi Gu , Wanlin Guo

It is widely recognized that the near-threshold slow fatigue crack growth (FCG) in metals is sensitive to their microstructures and the damage zone well within the crack tip plastic zone is the root form FCG. Here we find that near-threshold slow FCG can induce evolution of cyclic microplastic deformation which can significantly change the microstructures in a much larger region than the macroscopic crack tip plastic zone evaluated by classic continuum fracture mechanics theory in compact tension specimens of a Ni-based superalloy at both low and high stress ratios under ambient conditions. Detailed analyses utilizing electron backscatter diffraction and scanning electron microscopy examination reveal that, at low stress ratio of 0.05, near-threshold FCG induces evolution in microstructures through twinning and exhibited hysteresis. While microstructure evolution at high stress ratio of 0.7 is dominated by lattice torsion resulting from dislocation pile-up, without hysteresis. This shows that irreversible cyclic microplastic deformation can induce microstructure changes far outside the macroscopic crack tip plastic zone where the cyclic stress is far below the yield strength of material. The results fundamentally challenge the conventional conception that damage accumulation only occurs within the macroscopic plastic zone, deepen our understanding of why fatigue can occur well below the traditional fatigue limit and FCG continues below the “threshold value”, guiding our design for long life structures.

金属的近阈值慢疲劳裂纹扩展（FCG）对其显微组织非常敏感，而位于裂纹尖端塑性区内的损伤区是FCG的根源。研究发现，在低应力比和高应力比的环境条件下，近阈值慢速FCG可以诱导循环微塑性变形的演化，而非经典连续断裂力学理论所评价的宏观裂纹尖端塑性区，在更大的区域内显著改变微观组织。电子后向散射衍射和扫描电镜分析表明，在0.05的低应力比下，近阈值FCG诱导微观组织通过孪晶演化，并表现出迟滞性。而在高应力比为0.7时，微观组织演化以位错堆积引起的晶格扭转为主，无迟滞现象。这表明不可逆的循环微塑性变形可以在远低于材料屈服强度的宏观裂纹尖端塑性区之外引起微观结构的变化。这些结果从根本上挑战了损伤积累只发生在宏观塑性区内的传统观念，加深了我们对为什么疲劳可以远远低于传统疲劳极限而FCG持续低于“阈值”的理解，指导了我们对长寿命结构的设计。

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引用次数: 0

Phase boundary and defect dependent high cycle fatigue behavior in AlCoCrFeNi2.1 eutectic high-entropy alloy cocrfeni2.1共晶高熵合金的相界和缺陷高周疲劳行为

IF 6.8 2区材料科学 Q1 ENGINEERING, MECHANICAL

International Journal of Fatigue

Pub Date : 2026-05-01 Epub Date: 2025-12-27 DOI: 10.1016/j.ijfatigue.2025.109462

Xiaochuan Yang , Tianxin Li , Jiang Yang , Mingpan Wan , Zhong Zhang , Chaowen Huang

The AlCoCrFeNi_2.1 (Ni21) eutectic high-entropy alloy (EHEA) exhibits a dual-phase heterogeneous microstructure that contributes to its high strength and ductility. However, its high cycle fatigue (HCF) damage mechanisms remain insufficiently understood and restrict its practical application. In this study, the HCF behavior of the as-cast Ni21 alloy was systematically investigated. The alloy exhibits a fatigue strength of approximately 297 MPa (σ_-1 (10⁷)), corresponding to a fatigue ratio (σ_-1 (10⁷)/YS) of 0.512. Under cyclic loading, dislocations are preferentially activated in the face-centered cubic (FCC) phase and accumulate at phase boundaries (PBs), where they induce stress concentration and trigger fatigue microcrack initiation. Meanwhile, nano-precipitates within the ordered body-centered cubic (B2) phase effectively hinder dislocations transmission across PBs, thereby enhancing resistance to fatigue crack initiation. The combined contribution of the dual-phase microstructure and nano- precipitates plays a critical role in extending fatigue life. Furthermore, fatigue crack propagation is most effectively suppressed when the crack growth direction intersects PBs at angles between 40° and 70°. Considerable scatter in the HCF data is observed, primarily resulting from casting defects such as blowholes. Overall, these findings highlight that further improvements in the HCF performance of Ni21 alloy will require improved casting quality or appropriate thermo-mechanical treatments.

AlCoCrFeNi2.1 （Ni21）共晶高熵合金（EHEA）具有双相非均相组织，具有较高的强度和塑性。然而，对其高周疲劳损伤机理的认识尚不充分，制约了其实际应用。本研究系统地研究了铸态Ni21合金的HCF行为。合金的疲劳强度约为297 MPa (σ-1(107))，对应的疲劳比（σ-1 (107)/YS）为0.512。在循环加载下，位错优先在面心立方（FCC）相中激活，并在相界（PBs）处积累，从而引起应力集中并引发疲劳微裂纹萌生。同时，有序体心立方（B2）相内的纳米沉淀有效地阻碍了位错在PBs中的传播，从而增强了抗疲劳裂纹萌生的能力。双相组织和纳米析出相的共同作用对延长疲劳寿命起着至关重要的作用。当裂纹扩展方向与疲劳裂纹扩展方向成40°~ 70°夹角相交时，疲劳裂纹扩展得到最有效的抑制。在HCF数据中观察到相当大的分散，主要是由于铸造缺陷，如气孔。总之，这些研究结果表明，进一步提高Ni21合金的HCF性能需要提高铸造质量或适当的热机械处理。

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引用次数: 0

Thermo-mechanical fatigue behavior and failure mechanisms of DZ125 superalloy considering effects of extremely high temperature ramp rates 考虑极高温度斜坡速率影响的DZ125高温合金热机械疲劳行为及失效机制

IF 6.8 2区材料科学 Q1 ENGINEERING, MECHANICAL

International Journal of Fatigue

Pub Date : 2026-05-01 Epub Date: 2025-12-15 DOI: 10.1016/j.ijfatigue.2025.109443

Zhenlei Li , Bolin Li , Guo Li , Shaochen Bao , Lei Qi , Shuiting Ding

The thermo-mechanical fatigue (TMF) behavior and failure mechanisms of hollow tubular DZ125 Ni-based superalloy specimens were investigated under a wide range of temperature change rates, ranging from 10 to 100°C/s. A novel TMF experimental system was developed, capable of achieving extremely high temperature ramp rates far higher than conventional tests. Isothermal fatigue (IF) tests at 1000 °C were also conducted for comparison. Results show that both cyclic strain response and fracture morphology are affected by temperature change rates. Compared to low rates, extremely high ramp rates caused large variability in fatigue life, as the cycles to failure increased by about 6.5 times on average when the rate increased from 10 ℃/s to 100 ℃/s. This trend was explained by an analytical framework of damage competition: at lower rates, creep damage dominates, thereby reducing the fatigue lives. A comparison between TMF and IF under the same frequencies shows that TMF tests exhibit stronger rate sensitivity than IF. This indicates that the life differences cannot be attributed to thermal variation alone, as temperature change rate is a significant factor. These findings demonstrate the necessity of considering temperature change rate in TMF failure, especially under extremely rapidly varying thermal environments.

研究了DZ125 ni基高温合金空心管试样在10 ~ 100℃/s范围内的热机械疲劳（TMF）行为和失效机理。开发了一种新型的TMF实验系统，能够实现远高于常规测试的极高温度斜坡率。还进行了1000℃的等温疲劳（IF）试验进行比较。结果表明，温度变化速率对循环应变响应和断口形貌均有影响。与低速率相比，极高的斜坡速率导致疲劳寿命变化较大，当速率从10℃/s增加到100℃/s时，失效循环次数平均增加约6.5倍。这种趋势可以用损伤竞争的分析框架来解释：在较低的速率下，蠕变损伤占主导地位，从而降低了疲劳寿命。在相同频率下，对TMF和中频的比较表明，TMF测试表现出比中频更强的速率灵敏度。这表明，寿命差异不能仅仅归因于热变化，因为温度变化率是一个重要因素。这些发现表明，考虑温度变化率在TMF失效中的必要性，特别是在极快速变化的热环境下。

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引用次数: 0

Fatigue performance of Ti6Al4V lattices: relative density as a partial quantitative predictor Ti6Al4V晶格的疲劳性能：相对密度作为部分定量预测因子

IF 6.8 2区材料科学 Q1 ENGINEERING, MECHANICAL

International Journal of Fatigue

Pub Date : 2026-05-01 Epub Date: 2025-12-16 DOI: 10.1016/j.ijfatigue.2025.109447

Pietro Foti , Asghar Heydari Astaraee , Sara Bagherifard , Anton du Plessis , Di Wan , Filippo Berto , Nima Razavi

Lattice structures realized through additive manufacturing have garnered increasing interest within both academia and industry in recent years. Various factors, including unit cell topology, base material, heat treatments, and relative density, significantly influence the overall behaviour of these architectured structures. This study specifically examines the compressive mechanical behaviour of solid-based gyroid lattices made of Ti6Al4V alloy through Laser Powder Bed Fusion (PBF-LB) technique. Specimens with four different relative densities were produced to investigate the impact of this parameter on the compressive behaviour (quasi-static and fatigue); furthermore, each relative density category included two sets of specimens to evaluate the effect of annealing and Hot Isostatic Pressing (HIP) as post-processing techniques. Micro-CT scans, microstructural, postmortem and finite element analyses were included to further evaluate the failure mechanisms and explain the observed experimental results. Furthermore, the behaviour documented in the present analysis has been correlated with a wide fatigue dataset retrieved from literature in an effort to dig deeper into the behaviour of these structures. The results, together with the retrieved dataset, allowed for a more comprehensive understanding also considering aspects such as yielding effect, surface roughness and notch mechanics. It has been proved that the use of optimized process parameters and cheaper heat treatments is able to match the beneficial effects expected by HIP. Furthermore, easy-to-use methodologies to account for the reduction in strength due to the change in relative density presented in the literature, such as effective and normalized stress, have been considered to evaluate their accuracy, but also their limitations.

近年来，通过增材制造实现的点阵结构在学术界和工业界都引起了越来越多的兴趣。各种因素，包括单元胞拓扑结构、基础材料、热处理和相对密度，显著影响这些建筑结构的整体行为。本研究通过激光粉末床熔合（PBF-LB）技术研究了由Ti6Al4V合金制成的固体基陀螺晶格的压缩力学行为。制作了四种不同相对密度的试样，以研究该参数对压缩行为（准静态和疲劳）的影响；此外，每个相对密度类别包括两组样品，以评估退火和热等静压（HIP）作为后处理技术的效果。通过显微ct扫描、显微组织、尸检和有限元分析来进一步评估破坏机制并解释观察到的实验结果。此外，本分析中记录的行为与从文献中检索的广泛疲劳数据集相关联，以更深入地挖掘这些结构的行为。结果与检索到的数据集一起，可以更全面地了解屈服效应、表面粗糙度和缺口力学等方面。实践证明，采用优化后的工艺参数和较便宜的热处理方法能够达到HIP预期的有益效果。此外，易于使用的方法来解释由于文献中提出的相对密度变化而导致的强度降低，例如有效应力和归一化应力，已被考虑评估其准确性，但也有其局限性。

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引用次数: 0

An effective approach for identifying fatigue-critical defects from X-ray 3D reconstruction: Example in L-PBF AlSil0Mg alloys x射线三维重建识别疲劳临界缺陷的有效方法：以L-PBF AlSil0Mg合金为例

IF 6.8 2区材料科学 Q1 ENGINEERING, MECHANICAL

International Journal of Fatigue

Pub Date : 2026-05-01 Epub Date: 2025-12-25 DOI: 10.1016/j.ijfatigue.2025.109457

Zhengkai Wu , Tianyu Qin , Jianguang Bao , Weijian Qian , Enrico Salvati , Shengchuan Wu , Rihan Da , Jiang Dong , Hiroyuki Toda

Internal defects have been widely believed as the physical origins of fatigue crack initiation and growth in additively manufactured (AM) metals, and the specific defect that triggers final failure typically dictates the overall fatigue life of critical safety equipment. To this regard, reliable identification of such critical defects among numerous of these imperfections is essential for accurate fatigue life prediction and defect-tolerant design. In this study, we investigate the geometric and spatial nature of porosity defects in laser powder bed fusion AlSi10Mg alloys, including their size, position, morphology, and orientation, and attempt elucidating their effect on fatigue resistance using high-resolution X-ray computed tomography (X-CT) and post-mortem fractographic analysis. Recognizing that image-based finite element analysis can be computationally intensive and that conventional defect descriptor may not fully capture the complexity of defect geometry and spatial context, we propose an effective Critical Defect Ranking Function (CDRF) metric that quantitatively integrates defect size, location, morphology, and orientation directly from large 3D X-CT imaging data. An effective defect size is adopted to ensure physical consistency, with the enhanced detrimental effect of near-surface defects considered. The CDRF enables direct, automated identification and ranking of fatigue-critical defects, and demonstrates predictive correlation with post-mortem experimental results. This robust, non-destructive framework facilitates defect-based reliability assessment and quality assurance in AM components.

内部缺陷被广泛认为是增材制造（AM）金属疲劳裂纹萌生和扩展的物理根源，而引发最终失效的特定缺陷通常决定了关键安全设备的整体疲劳寿命。在这方面，在众多缺陷中可靠地识别这些关键缺陷对于准确的疲劳寿命预测和缺陷容忍度设计至关重要。在这项研究中，我们研究了激光粉末床熔合AlSi10Mg合金孔隙缺陷的几何和空间性质，包括它们的大小、位置、形态和取向，并试图通过高分辨率x射线计算机断层扫描（X-CT）和尸检断口分析来阐明它们对抗疲劳性能的影响。认识到基于图像的有限元分析可能需要大量的计算，并且传统的缺陷描述符可能无法完全捕获缺陷几何和空间背景的复杂性，我们提出了一种有效的关键缺陷排序函数（CDRF）度量，该度量可以直接从大型3D X-CT成像数据中定量地集成缺陷尺寸、位置、形态和方向。采用有效的缺陷尺寸来保证物理一致性，并考虑了近表面缺陷增强的有害影响。CDRF能够直接、自动地识别疲劳临界缺陷并对其进行排序，并证明了与死后实验结果的预测相关性。这种强大的、非破坏性的框架促进了基于缺陷的可靠性评估和增材制造组件的质量保证。

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