Journal of Materials Research and Technology-Jmr&t最新文献_第9页

Oxidation and hot corrosion characteristics of YSZ/ NiCoCrAlY electrophoretically deposited on IN-738 IN-738表面电泳沉积YSZ/ NiCoCrAlY的氧化和热腐蚀特性

IF 6.6 2区材料科学 Q1 MATERIALS SCIENCE, MULTIDISCIPLINARY

Journal of Materials Research and Technology-Jmr&t

Pub Date : 2025-12-13 DOI: 10.1016/j.jmrt.2025.12.067

Anahita Shamsini, Mohsen Saremi, Mahmoud Heydarzadeh Sohi

Gas turbines require high inlet temperatures to increase their efficiency, yet Ni-based superalloy components may not tolerate such harsh environment. Thermal barrier coatings (TBCs) are applied to reduce thermal loads and protect them in aggressive conditions. Conventional fabrication techniques, such as thermal spraying and EB-PVD, are costly and restricted by line-of-sight limitations. Electrophoretic deposition (EPD) offers a flexible, cost-effective alternative for applying TBCs on Ni-based components. In this study, a YSZ/NiCoCrAlY system was deposited by EPD on IN-738. The coated material was subjected to different sintering temperatures of 800 and 1100 °C and then exposed to cyclic oxidation at 1100 °C and type II hot corrosion at 700 °C. Oxidation studies showed parabolic kinetics, and the first sign of failure was observed after 19 cycles (152 h). XRD patterns revealed the YSZ phase stability, and SEM images showed that the NiCoCrAlY bond coat retained cohesion and adhesion with no cracks or spallation after successive oxidation cycles. However, XRD detected spinel formation at the NiCoCrAlY/YSZ interface, which promoted spallation at the interface. Hot corrosion tests revealed that YSZ coatings sintered at 1100 °C exhibited higher resistance than those sintered at 800 °C, due to improved densification and reduced salt penetration. EDS results confirmed chromium oxide formation at the NiCoCrAlY/YSZ interface, whicsh further suppressed elemental diffusion from the bond coat into the top coat. These results demonstrate that EPD can provide an effective and low-cost approach to fabricate durable TBCs with resistance to oxidation and hot corrosion, competitive with conventional techniques.

燃气轮机需要较高的进口温度来提高效率，但镍基高温合金部件可能无法忍受如此恶劣的环境。热障涂层（tbc）用于减少热负荷并在恶劣条件下保护它们。传统的制造技术，如热喷涂和EB-PVD，成本高昂，而且受视线限制的限制。电泳沉积（EPD）为在镍基组件上应用tbc提供了一种灵活、经济的替代方案。在本研究中，采用EPD在In -738上沉积了YSZ/NiCoCrAlY体系。对涂层材料进行800℃和1100℃的不同烧结温度，然后在1100℃下进行循环氧化和700℃下进行II型热腐蚀。氧化研究显示抛物线动力学，在19个循环（152小时）后观察到第一个失败迹象。XRD和SEM结果表明，经过连续的氧化循环后，NiCoCrAlY结合层保持了内聚性和附着力，无裂纹和剥落现象。然而，XRD检测到NiCoCrAlY/YSZ界面处形成尖晶石，这促进了界面处的剥落。热腐蚀试验表明，在1100℃下烧结的YSZ涂层比在800℃下烧结的YSZ涂层具有更高的耐腐蚀性能，这是由于致密性的改善和盐渗透的减少。EDS结果证实，NiCoCrAlY/YSZ界面形成氧化铬，进一步抑制了元素从结合层向面层的扩散。这些结果表明，EPD可以提供一种有效且低成本的方法来制造具有抗氧化和抗热腐蚀的耐用tbc，与传统技术相比具有竞争力。

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引用次数: 0

Investigation of laser-flux cored arc hybrid welding of Q690D high strength steel: weld formation, microstructure evolution and mechanical performance Q690D高强度钢激光药芯电弧复合焊接研究：焊缝形成、显微组织演变及力学性能

IF 6.6 2区材料科学 Q1 MATERIALS SCIENCE, MULTIDISCIPLINARY

Journal of Materials Research and Technology-Jmr&t

Pub Date : 2025-12-13 DOI: 10.1016/j.jmrt.2025.12.122

Qingyong Liu , Pengcheng You , Xuedong Wu , Shinong Liao , Hangbiao Mi , Lingyun Feng , Xionghao Cheng , Houqin Wang , Binggang Zhang , Wei Guo , Binyan He

Q690D high-strength low alloy (HSLA) steel, renowned for its exceptional mechanical properties, is extensively employed in fabricating marine engineering equipment. Traditional laser-arc hybrid welding (LAHW) of medium-thick plates with solid wires exhibits limited alloying capabilities and wettability, causing undercut and humping defects. However, the unique structure and molten slag protection effect of flux-cored wires (FCWs) in the laser-flux cored arc hybrid welding (L-FCAHW) process demonstrate significant enhancement of the weld formation. In this work, L-FCAHW technique was developed to weld 10 mm thick Q690D HSLA steel. The interaction mechanisms between laser-induced keyhole dynamics, molten pool dynamics and flow behavior, as well as the metallurgical performance were investigated in detail. The results indicate that the slag covering effect of FCWs markedly improves the wettability of the molten pool and suppresses the undercut defects. Additionally, the formation of humping defects is influenced by the equilibrium between the vapor recoil force and the Marangoni effect. The underlying mechanism involves a dynamic balance among the vapor recoil force, surface tension, gravity, and arc pressure. The Fe–Ti–O slag system enhances the wettability of the molten metal, significantly refining the grain size. Microstructure in the arc zone (AZ) was predominated by martensite and quasi-polygonal ferrite, while the laser zone (LZ) was lath martensite. The tensile properties of the welded specimens obtained by L-FCAHW process were comparable to those of the base material. The impact toughness of the weld specimens is able to meet industry standards and ensures adequate impact toughness even at low temperature.

Q690D高强度低合金（HSLA）钢以其卓越的机械性能而闻名，广泛用于制造海洋工程设备。传统的激光-电弧复合焊接（LAHW）中厚板实心焊丝的合金化能力和润湿性有限，容易产生凹边和驼峰缺陷。然而，在激光-药芯电弧复合焊接（L-FCAHW）工艺中，药芯焊丝（FCWs）独特的结构和保护熔渣的效果显著地促进了焊缝的形成。本文采用L-FCAHW技术，对10mm厚Q690D HSLA钢进行了焊接。详细研究了激光诱导钥匙孔动力学、熔池动力学与流动行为及冶金性能之间的相互作用机理。结果表明：炉渣包渣效果显著提高了熔池的润湿性，抑制了凹边缺陷的产生；此外，驼峰缺陷的形成还受到蒸汽反冲力和马兰戈尼效应之间的平衡的影响。潜在的机制涉及蒸汽反冲力、表面张力、重力和电弧压力之间的动态平衡。Fe-Ti-O渣体系提高了熔融金属的润湿性，显著细化了晶粒尺寸。电弧区以马氏体和拟多边形铁素体为主，激光区以板条马氏体为主。L-FCAHW焊接试样的拉伸性能与母材相当。焊缝试样的冲击韧性符合行业标准，即使在低温下也能保证足够的冲击韧性。

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引用次数: 0

Influence of build orientation and thermal treatment on the fracture toughness of LPBF-manufactured 18Ni300 maraging steel 组织取向和热处理对lpbf制备的18Ni300马氏体时效钢断裂韧性的影响

IF 6.6 2区材料科学 Q1 MATERIALS SCIENCE, MULTIDISCIPLINARY

Journal of Materials Research and Technology-Jmr&t

Pub Date : 2025-12-13 DOI: 10.1016/j.jmrt.2025.12.134

Bruno Caetano dos Santos Silva , Luã Fonseca Seixas , Bruna Callegari , Rodolfo Lisboa Batalha , Luis Reis , Andersan dos Santos Paula , Leonardo Barbosa Godefroid , Gilmar Ferreira Batalha , Rodrigo Santiago Coelho

This study investigates the fracture behavior of 18Ni300 maraging steel manufactured via LPBF, comparing specimens on as-built condition and solubilization and aging treated. Specimens were fabricated in vertical and horizontal orientations, and fracture toughness was assessed using the crack tip opening displacement (CTOD) method. Comprehensive microstructural characterization was performed to evaluate microstructure, and fracture surface features. Results revealed anisotropic fracture behavior in the as-built condition, attributed to misalignment of the crack propagation paths with the melt pool boundaries. In contrast, heat-treated specimens exhibited a reduction in ductility and fracture toughness (CTOD values decreasing by up to 97 %), which was attributed to microstructure coarsening and martensite stabilization. Fractographic examination revealed a transition from ductile failure (characterized by plastic deformation and dimple coalescence) in the as-built condition to brittle features after thermal treatment. These findings reveal that fracture mechanisms in LPBF 18Ni300 are highly sensitive to microstructural features, which are governed by build orientation and heat treatment. This study reinforces the applicability of CTOD as a robust method for evaluating fracture performance in AM metallic components, providing insights into the interdependencies among processing conditions, microstructure evolution, and mechanical integrity. Furthermore, this study validates the use of CTOD method for reliable fracture toughness assessment in LPBF components, addressing the current scarcity of validated fracture mechanics by this method and providing a robust and reliable foundation for future structural integrity analyses of LPBF 18Ni300.

研究了LPBF法制备的18Ni300马氏体时效钢的断裂行为，比较了原位状态和增溶时效处理的试样。在垂直和水平方向上制作试样，并采用裂纹尖端张开位移（CTOD）法评估断裂韧性。进行了全面的显微组织表征，以评估显微组织和断口表面特征。结果表明，由于裂纹扩展路径与熔池边界不一致，在建成条件下出现了各向异性断裂行为。相比之下，热处理试样的延展性和断裂韧性下降（CTOD值下降高达97%），这是由于显微组织粗化和马氏体稳定化。断口检查显示，在建成状态下的韧性破坏（以塑性变形和韧窝合并为特征）向热处理后的脆性特征转变。这些结果表明，LPBF 18Ni300的断裂机制对微观组织特征高度敏感，微观组织特征受构建取向和热处理的控制。这项研究强化了CTOD作为一种评估增材制造金属部件断裂性能的可靠方法的适用性，并提供了对加工条件、微观结构演变和机械完整性之间相互依赖关系的见解。此外，本研究验证了CTOD方法在LPBF构件断裂韧性可靠评估中的应用，解决了目前该方法验证断裂力学的不足，为未来LPBF 18Ni300的结构完整性分析提供了稳健可靠的基础。

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引用次数: 0

Study on damage mechanism and wear behavior of rail welding joints under controlled kinetic energy 可控动能下钢轨焊接接头损伤机理及磨损行为研究

IF 6.6 2区材料科学 Q1 MATERIALS SCIENCE, MULTIDISCIPLINARY

Journal of Materials Research and Technology-Jmr&t

Pub Date : 2025-12-13 DOI: 10.1016/j.jmrt.2025.12.133

Mingxue Shen , Yujie Mu , Jiadi Lian , Lang Mei , Qiuping Li , Shaopeng Liu

Welded joints are the vulnerable points of seamless steel rails, and their resistance to impact wear is crucial for the safety, stability, and comfort of high-speed trains. However, research on the impact wear behavior of welded joints is limited. This study employed a self-made impact wear tester, utilizing GCr15 balls as a counterpart, to systematically analyze the wear behavior in typical areas of rail welded joints under a controlled impact energy of 25000 mJ. Furthermore, by varying the impact velocities (60 mm/s, 80 mm/s, 100 mm/s, and 120 mm/s), we thoroughly evaluated the effects of material characteristics and impact velocity on wear behavior. The results indicated that the base metal demonstrated the highest resistance to impact wear, while the heat-affected zone exhibited the lowest resistance. Notably, material accumulation was observed at the edges of the impact craters, suggesting significant plastic flow during repeated collisions. In the initial phase of repeated impacts, the size of the impact crater increased rapidly, with plastic deformation being the primary damage mechanism. Once contact stress and yield strength reached equilibrium, the energy absorbed by each collision mainly contributed to crack initiating and propagating. Afterward, the primary damage mechanisms in the welding zone and heat-affected zone shifted to oxidation and fatigue wear. Compared to the rapid increase in wear volume caused by plastic deformation, the rise in wear volume attributed to fatigue wear was minimal.

焊接接头是无缝钢轨的薄弱环节，其抗冲击磨损性能对高速列车的安全性、稳定性和舒适性至关重要。然而，对焊接接头冲击磨损性能的研究却很少。本研究采用自制冲击磨损试验机，以GCr15钢球为对照品，系统分析了钢轨焊接接头在控制25000 mJ冲击能量下典型区域的磨损行为。此外，通过改变冲击速度（60mm /s、80mm /s、100mm /s和120mm /s），我们全面评估了材料特性和冲击速度对磨损行为的影响。结果表明，母材对冲击磨损的耐磨性最高，热影响区对冲击磨损的耐磨性最低。值得注意的是，在陨石坑边缘观察到物质堆积，这表明在反复碰撞中有明显的塑性流动。在重复撞击的初始阶段，弹坑尺寸迅速增大，塑性变形是主要的损伤机制。一旦接触应力和屈服强度达到平衡，每次碰撞所吸收的能量主要是裂纹的产生和扩展。随后，焊接区和热影响区的主要损伤机制转变为氧化和疲劳磨损。与塑性变形引起的磨损量的快速增加相比，疲劳磨损引起的磨损量的增加是最小的。

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引用次数: 0

Effect of super-solidus heat treatments on microstructure and homogenization of CMSX-4 plus single crystal nickel-based superalloy 超固相热处理对CMSX-4 +单晶镍基高温合金组织及均匀化的影响

IF 6.6 2区材料科学 Q1 MATERIALS SCIENCE, MULTIDISCIPLINARY

Journal of Materials Research and Technology-Jmr&t

Pub Date : 2025-12-13 DOI: 10.1016/j.jmrt.2025.12.128

Inmaculada López-Galilea, Lisa Hecker, Sebastian Weber

The development of advanced single crystal Ni-based superalloys with high refractory element content has enabled significant improvements in high-temperature mechanical properties but has also introduced challenges related to chemical segregation and microstructural heterogeneity in as-cast materials. Conventional solution annealing heat treatments for homogenization are lengthy and can increase porosity, limiting the practical application of these alloys. This study systematically investigates the effects of isothermal super-solidus and super-solidus hot isostatic pressing heat treatments on the microstructure and chemical homogenization of the third-generation single crystal Ni-based superalloy CMSX-4 Plus. Phase transformation temperatures were determined using differential scanning calorimetry and thermodynamic calculations to guide the selection of super-solidus heat treatment parameters. Microstructural evolution, porosity, and chemical segregation were characterized by advanced electron microscopy and energy-dispersive X-ray spectrometry, while DICTRA kinetic simulations provided complementary insights. Super-solidus heat treatments were found to promote rapid dissolution of eutectic regions and substantial reduction of chemical segregation, with homogenization strongly dependent on temperature and holding time. The optimized super-solidus hot isostatic pressing process, comprising two holding stages at 1345 °C and 1350 °C under 100 MPa isostatic pressure, achieved near-complete elimination of porosity and residual eutectics, while preserving the single crystal structure, in a fraction of the time required by conventional treatments. These findings establish a scientific and practical foundation for accelerated homogenization of high-refractory-content single crystal superalloys, supporting improved processing efficiency and microstructural quality in advanced turbine applications.

具有高耐火元素含量的先进单晶镍基高温合金的发展使其高温机械性能得到了显着改善，但也带来了与铸态材料的化学偏析和显微组织不均匀性相关的挑战。传统的均匀化固溶退火热处理时间长，而且会增加孔隙率，限制了这些合金的实际应用。本研究系统地研究了等温超固和超固热等静压热处理对第三代单晶镍基高温合金CMSX-4 Plus组织和化学均匀化的影响。采用差示扫描量热法和热力学计算确定相变温度，以指导超固相热处理参数的选择。通过先进的电子显微镜和能量色散x射线光谱技术表征了微观结构演化、孔隙度和化学偏析，而DICTRA动力学模拟提供了补充的见解。研究发现，超固相热处理促进了共晶区域的快速溶解和化学偏析的显著减少，均质化强烈依赖于温度和保温时间。优化的超固相热等静压工艺，包括1345°C和1350°C两个保温阶段，在100 MPa等静压下，在保留单晶结构的同时，几乎完全消除了孔隙和残余共晶，而所需的时间是常规处理的一小部分。这些发现为高耐火含量单晶高温合金的加速均匀化奠定了科学和实践基础，支持了先进涡轮应用中提高加工效率和显微组织质量。

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引用次数: 0

A unified constitutive modelling for predicting low cycle behaviour and fatigue life of Eurofer97 under coupled temperature and neutron irradiation effects 温度和中子辐照耦合作用下Eurofer97低周性能和疲劳寿命预测的统一本构模型

IF 6.6 2区材料科学 Q1 MATERIALS SCIENCE, MULTIDISCIPLINARY

Journal of Materials Research and Technology-Jmr&t

Pub Date : 2025-12-13 DOI: 10.1016/j.jmrt.2025.12.123

Jianxin Liu , Xiaowei Wang , Dagang Wang , Lihua Wang , Magd Abdel Wahab

Reduced Activation Ferritic/Martensitic (RAFM) steel, like Eurofer97, is a reference structural material for fusion reactors (ITER, DEMO), where extreme conditions (irradiation, high temperatures, complex loads) cause Low Cycle Fatigue (LCF). Accurate LCF prediction is vital for safety but challenged by coupled temperature, irradiation, and specimen size effects, often isolated in current models. A unified model integrating these within a Continuum Damage Mechanics (CDM) model is needed. This study presents a validated unified viscoplastic damage model, implemented in ABAQUS as a user-defined material subroutine (UMAT), integrating an improved CDM approach into a modified Chaboche model. It includes temperature dependent parameters for kinematic and isotropic hardening, a specimen size correction, and a temperature and irradiation dose dependent irradiation hardening model, all validated against extensive Eurofer97 LCF data (Room Temperature (RT)–450 °C, various strains, sizes, irradiated dose). The model accurately simulated Eurofer97's cyclic behaviour (two stage softening) and predicted LCF reduction from size effects. Crucially, it captured the complex temperature dependent effect of neutron irradiation at 16.3 displacements per atom (dpa) on LCF lifetime (e.g., extension at 250 °C, negligible at 450 °C), matching defect mechanisms. LCF lifetime predictions for combined effects were generally within a factor of 1.5–2.0 of experimental data, with interpolated parameters useful for uncalibrated temperatures. This research offers a validated tool for predicting Eurofer97's LCF under combined influences, aiding reactor design, safety, and advancing constitutive modelling.

低活化铁素体/马氏体（RAFM）钢，如Eurofer97，是聚变反应堆（ITER， DEMO）的参考结构材料，在极端条件下（辐照，高温，复杂载荷）会导致低周疲劳（LCF）。准确的LCF预测对安全至关重要，但受到温度、辐照和样品尺寸耦合效应的挑战，这些效应在当前模型中通常是孤立的。在连续损伤力学（CDM）模型中需要一个统一的模型。本研究提出了一个经过验证的统一粘塑性损伤模型，该模型在ABAQUS中作为用户定义的材料子程序（UMAT）实现，将改进的CDM方法集成到改进的Chaboche模型中。它包括运动和各向同性硬化的温度相关参数，试样尺寸校正，以及温度和辐照剂量相关的辐照硬化模型，所有这些都针对广泛的Eurofer97 LCF数据（室温(RT) -450°C，各种菌株，尺寸，辐照剂量）进行验证。该模型准确地模拟了Eurofer97的循环行为（两阶段软化），并预测了尺寸效应对LCF的降低。至关重要的是，它捕获了每原子16.3位移（dpa）的中子辐照对LCF寿命的复杂温度依赖效应（例如，在250°C时延长，在450°C时可以忽略不计），匹配缺陷机制。综合效应的LCF寿命预测通常在实验数据的1.5-2.0因子内，内插参数对未校准的温度有用。这项研究为预测Eurofer97在综合影响下的LCF提供了一个有效的工具，有助于反应堆设计、安全性和推进本构建模。

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引用次数: 0

Biodegradable magnesium alloys for short-term orthopedic implants: properties, surface modification and biological response 短期骨科植入物用可生物降解镁合金：性能、表面改性和生物反应

IF 6.6 2区材料科学 Q1 MATERIALS SCIENCE, MULTIDISCIPLINARY

Journal of Materials Research and Technology-Jmr&t

Pub Date : 2025-12-13 DOI: 10.1016/j.jmrt.2025.12.038

Barbara Rynkus , Alessandra Scano , Silvia Puxeddu , Fabrizio Angius , Guido Ennas , Janusz Szewczenko

Orthopedic diseases pose a significant challenge in the medical field, often requiring innovative solutions to address the unique needs of the patient. Orthopedic implants increasingly demand materials that not only meet mechanical and biological requirements, but also actively participate in the healing process. Magnesium and magnesium-based alloys are lightweight materials that have emerged as promising candidates because of their biodegradability, biocompatibility, and mechanical properties, which closely resemble natural bone. A key advantage of magnesium alloys lies in their ability to slowly degrade in vivo, which translates into their potential for use in temporary, bioabsorbable implants, thus eliminating the need for surgical removal. However, rapid and uncontrolled corrosion remains a critical barrier to their clinical translation. This review provides a focused analysis of current strategies to engineer the controlled biodegradation of magnesium-based orthopedic implants. We critically examine the role of alloying elements, surface modification techniques, and biological interactions in modulating degradation behavior. Particular attention is paid to the interaction between material design and biological response, which is essential for maintaining implant functionality during tissue regeneration. By identifying challenges and highlighting emerging directions, this review aims to support the development of next-generation biodegradable magnesium-based implants tailored for orthopedic applications. We wish to inspire more research and development into magnesium alloys biomaterials for the orthopedic field.

骨科疾病是医学领域的一个重大挑战，通常需要创新的解决方案来满足患者的独特需求。骨科植入物对材料的要求越来越高，不仅要满足力学和生物学要求，而且要积极参与愈合过程。镁和镁基合金是一种轻质材料，因其生物可降解性、生物相容性和机械性能与天然骨非常相似而成为有希望的候选材料。镁合金的一个关键优势在于它们能够在体内缓慢降解，这意味着它们有可能用于临时的、生物可吸收的植入物，从而消除了手术移除的需要。然而，快速和不受控制的腐蚀仍然是其临床转化的关键障碍。这篇综述提供了一个重点分析目前的策略，工程控制生物降解镁基骨科植入物。我们严格检查合金元素的作用，表面改性技术，和生物相互作用在调节降解行为。特别关注材料设计和生物反应之间的相互作用，这对于在组织再生过程中维持植入物的功能至关重要。通过识别挑战和突出新兴方向，本综述旨在支持为骨科应用量身定制的下一代可生物降解镁基植入物的开发。我们希望在骨科领域激发更多的镁合金生物材料的研究和开发。

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引用次数: 0

Microstructure, thermo-physical and mechanical properties of heterogeneous Al/Al–70Si composites 非均相Al/Al - 70si复合材料的显微组织、热物理和力学性能

IF 6.6 2区材料科学 Q1 MATERIALS SCIENCE, MULTIDISCIPLINARY

Journal of Materials Research and Technology-Jmr&t

Pub Date : 2025-12-12 DOI: 10.1016/j.jmrt.2025.12.074

Zixin Wu , Hao Yan , Qian Han , Nan Chen , Xiang Peng , Richu Wang , Zhiyong Cai

To address the brittleness of Al–50Si alloys caused by coarse and angular silicon (Si) phases, three Al/Al–70Si composites with distinct heterogeneous structures were fabricated and analyzed. Three composites, designated SAl–50Si, FAl–50Si, and MAl-50Si, were produced by hot-pressing mixtures of Al–70Si alloy powder with spherical, flaky, and ball-milled aluminum (Al) powders, respectively. All three composites exhibited a heterogeneous microstructure comprising two distinct regions: pure Al and Al–70Si alloy. However, the size and distribution of these regions, along with the grain characteristics (e.g., size and boundary misorientation) of the Al and Si phases, differed significantly depending on the morphology of the initial Al powder. The thermal conductivity and coefficient of thermal expansion of the three composites followed a descending order of SAl–50Si, MAl-50Si, and FAl–50Si. Compared to the Al–50Si alloy, the SAl–50Si composite exhibits a 72.1 % increase in fracture strain while maintaining a comparable bending strength. The FAl–50Si composite exhibited an 11.43 % increase in bending strength and a 19.6 % enhancement in fracture strain. Room-temperature fracture toughness measurements using the single edge notch bending (SENB) method confirmed the significantly enhanced toughness of the SAl–50Si and FAl–50Si composites. Spherical and flaky Al powders improve toughness while maintaining strength, offering a feasible, scalable strategy for high-performance high-silicon Al alloys and providing reference for their practical use in fields requiring good thermal management and structural reliability.

为解决Al - 50si合金因硅相粗大、棱角分明造成的脆性问题，制备并分析了3种具有不同非均相结构的Al/Al - 70si复合材料。将Al- 70si合金粉末与球形、片状和球磨铝粉热压混合制备了Al- 50si、Al- 50si和MAl-50Si三种复合材料。三种复合材料均表现出由纯Al和Al - 70si合金两个不同区域组成的异质显微组织。然而，这些区域的大小和分布，以及Al相和Si相的晶粒特征（如尺寸和边界取向偏差），根据初始Al粉末的形貌而有显著差异。三种复合材料的导热系数和热膨胀系数依次为SAl-50Si、MAl-50Si、al - 50si。与Al-50Si合金相比，Al-50Si复合材料的断裂应变提高了72.1%，同时保持了相当的抗弯强度。FAl-50Si复合材料的抗弯强度提高11.43%，断裂应变提高19.6%。采用单边缘缺口弯曲法（SENB）测量室温断裂韧性，证实了al - 50si和al - 50si复合材料的韧性显著增强。球形和片状Al粉末在保持强度的同时提高了韧性，为高性能高硅铝合金提供了可行的、可扩展的策略，并为其在需要良好热管理和结构可靠性的领域的实际应用提供了参考。

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引用次数: 0

Laser directed energy deposition of the refractory compositionally complex alloy TMT-8Cr–10Al: Processability, microstructural evolution and phase formation 激光定向能沉积难熔复合合金TMT-8Cr-10Al：可加工性、显微组织演变和相形成

IF 6.6 2区材料科学 Q1 MATERIALS SCIENCE, MULTIDISCIPLINARY

Journal of Materials Research and Technology-Jmr&t

Pub Date : 2025-12-12 DOI: 10.1016/j.jmrt.2025.12.105

Alexander Rieschl , Leonie Düfert , Florian Nahr , Nils Ellendt , Olaf Stelling , Steffen Neumeier , Thomas Niendorf , Michael Schmidt , Dominic Bartels

Refractory compositionally complex alloys (RCCAs) represent a promising class of materials that extend the concept of high-entropy alloys (HEAs) by incorporating high-melting-point refractory elements. To date, the production of RCCAs has been limited to laboratory scale, with quantities insufficient for industrial application. In the present study, the RCCA TMT-8Cr–10Al was processed through laser directed energy deposition (DED-LB/M), a more flexible alternative to traditional, lab scale methods such as repetitive arc melting. Samples were successfully synthesized and further characterized in terms of deposition quality, microstructure, chemical and phase composition, and mechanical hardness. The fabricated samples show porosity levels as low as 0.3 % and hardness values up to 1000 HV1. In addition to the widespread presence of intermetallic phases, a notable deviation from the expected body-centered cubic (BCC) structure toward a hexagonal-close-packed (HCP) structure is observed at laser powers of 800 W and 1200 W. The microstructure exhibits largely non-directional, dendritic, equiaxed grains. Altogether, these findings confirm the feasibility of producing TMT-8Cr–10Al by DED and provide a solid basis for future efforts aimed at scaling up processing and optimizing the mechanical performance of RCCAs.

耐火成分复杂合金（RCCAs）是一类很有前途的材料，它通过加入高熔点耐火元素来扩展高熵合金（HEAs）的概念。迄今为止，rcca的生产仅限于实验室规模，数量不足以用于工业应用。在本研究中，RCCA TMT-8Cr-10Al通过激光定向能沉积（ed - lb /M）进行加工，这是一种更灵活的替代传统的实验室规模方法，如重复电弧熔化。成功地合成了样品，并从沉积质量、微观结构、化学和相组成以及机械硬度等方面对样品进行了进一步表征。制备的样品孔隙率低至0.3%，硬度值高达1000 HV1。除了广泛存在的金属间相外，在800 W和1200 W的激光功率下，还观察到从预期的体心立方（BCC）结构向六边形紧密堆积（HCP）结构的明显偏离。显微组织主要表现为无方向性、枝晶、等轴晶粒。总之，这些发现证实了用DED生产TMT-8Cr-10Al的可行性，并为未来扩大RCCAs的加工规模和优化机械性能提供了坚实的基础。

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引用次数: 0

Finite element modeling of thermal conduction in spherical Al2O3 based composite materials 球形Al2O3基复合材料热传导的有限元模拟

IF 6.6 2区材料科学 Q1 MATERIALS SCIENCE, MULTIDISCIPLINARY

Journal of Materials Research and Technology-Jmr&t

Pub Date : 2025-12-12 DOI: 10.1016/j.jmrt.2025.12.076

Mantang He, Mengyang Sang, Tong Fu, Tingting Yang, Ye Li, Quanli Jia

In conventional finite element simulations of heat transfer in polydisperse spherical Al₂O₃ grains (SAG)/silicone rubber systems, a single median particle size has commonly been adopted for simplification. The simplified modeling approach that neglected particle size distribution effect, which led to markable inaccuracies in thermal transport predictions. To overcome this limitation, a three-dimensional stochastic distribution model of SAG/silicone rubber composites was developed in this manuscript. The relationships among the particle size distribution, volume fraction, and three-dimensional thermal conduction network of SAG with respect to the thermal performance of the composites were comprehensively analyzed. At a volume fraction of 45 vol% SAG, the effective thermal conductivity remained nearly unchanged despite variations in the particle size distribution of SAG. At 60 vol% SAG, the effective thermal conductivity increased significantly, and a distinct dependence on the particle size distribution was identified. Three-dimensional thermal conduction networks were constructed, incorporating variations in both particle size distribution and volume fraction. Quantitative analysis based on contact number and contact distance revealed that the contact distance played a critical role in governing thermal transport in SAG/silicone rubber composites.

在传统的多分散球形Al2O3晶粒(SAG)/硅橡胶体系传热有限元模拟中，通常采用单一中值粒度进行简化。简化的模拟方法忽略了粒径分布的影响，导致热输运预测存在明显的不准确性。为了克服这一局限性，本文建立了一个SAG/硅橡胶复合材料的三维随机分布模型。综合分析了表面活性剂的粒径分布、体积分数和三维导热网络对复合材料热性能的影响。当表面活性剂体积分数为45 vol%时，有效导热系数几乎保持不变，而表面活性剂的粒径分布却发生了变化。在60 vol% SAG时，有效导热系数显著增加，并且与粒径分布有明显的相关性。构建了包含颗粒尺寸分布和体积分数变化的三维热传导网络。基于接触数和接触距离的定量分析表明，接触距离对SAG/硅橡胶复合材料的热传递起关键作用。

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引用次数: 0