Materials Science and Engineering: A最新文献_第6页

Modulated precipitation of dispersoids and strength-ductility synergy via multi-step pre-treatments in an Al-Mg-Mn-Fe-Zr-Cr-Si alloy Al-Mg-Mn-Fe-Zr-Cr-Si合金多步预处理中分散体的调制析出和强度-塑性协同作用

IF 7 2区材料科学 Q1 MATERIALS SCIENCE, MULTIDISCIPLINARY

Materials Science and Engineering: A

Pub Date : 2026-01-19 DOI: 10.1016/j.msea.2026.149809

Ziyan Hu , Feng Qian , Jinyue Li , Chunan Li , Zijian Wang , Yang Li , Chun Guo , Shiwei Pan , Xingwang Cheng

Conventional 5xxx Al-Mg alloys are typically non-heat-treatable, with their strength limited by solid solution and work hardening. Dispersion strengthening is a potent strategy to overcome this limitation, but its effectiveness is often hindered by the sluggish and insufficient precipitation of thermally stable dispersoids. To promote dispersion kinetics, this work introduced a multi-step pre-treatment, integrating pre-aging (PA, 300 °C/8 h) and pre-straining (PS, 10 % cold rolling), in a novel Al-Mg-Mn-Fe-Zr-Cr-Si alloy. This PA + PS protocol constructed a unique composite microstructure, featuring Mn-rich solute clusters, β-Mg₂Si nanoparticles and a high density of dislocations. Upon subsequent aging at 400 °C, the dislocation networks strongly interacted with β-Mg₂Si to cooperatively facilitate the heterogeneous nucleation of Mn-rich dispersoids, while the residual Mn-rich solute clusters in Al-matrix progressively transformed into dispersoids. This dual precipitation pathway effectively accelerated the aging kinetics and enhanced the spatial uniformity of dispersoids, thus drastically minimizing dispersoid-free zones (DFZs). Consequently, samples subjected to PA + PS exhibited a superior strength-ductility synergy after aging at 400 °C for 12 h, with yield strength, ultimate strength and elongation increased by 34 %, 40 % and 23 % over the as-cast counterpart. Furthermore, it demonstrated exceptional thermal stability, with negligible loss of strength even after prolonged 400 °C aging until 200 h, overwhelming the PS pre-treated and as-cast samples. This work establishes a transformative dispersion-strengthening paradigm mediated by the synergy of pre-aging and pre-straining, providing foundational insights for developing advanced, thermally stable 5xxx alloys with high strength-ductility synergy.

传统的5xxx铝镁合金通常是不可热处理的，其强度受固溶体和加工硬化的限制。色散强化是克服这一限制的有效策略，但其有效性往往受到热稳定色散缓慢和不充分沉淀的阻碍。为了促进弥散动力学，本研究引入了一种新型Al-Mg-Mn-Fe-Zr-Cr-Si合金的多步骤预处理，将预时效（PA, 300°C/8 h）和预应变（PS， 10%冷轧）结合起来。这种PA + PS方案构建了独特的复合微观结构，具有富mn溶质团簇、β-Mg2Si纳米颗粒和高密度位错。在随后的400℃时效过程中，位错网络与β-Mg2Si强烈相互作用，共同促进富mn弥散体的非均相成核，而al基体中残余的富mn溶质团簇逐渐转变为弥散体。这种双重沉淀途径有效地加速了时效动力学，增强了弥散体的空间均匀性，从而大大减少了无弥散区（DFZs）。因此，经过PA + PS处理的样品在400℃时效12 h后表现出优异的强度-塑性协同效应，其屈服强度、极限强度和延伸率比铸态分别提高了34%、40%和23%。此外，它表现出优异的热稳定性，即使在400°C时效至200小时后，强度损失也可以忽略不计，超过PS预处理和铸态样品。这项工作建立了一种由预时效和预应变协同作用介导的变异性弥散强化范式，为开发具有高强度-塑性协同作用的先进、热稳定的5xxx合金提供了基础见解。

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引用次数: 0

Simultaneous enhancement of strength and ductility in Al-Cu-Li alloys with a moderate Cu/Li ratio via minor pre-deformation 适度Cu/Li比的Al-Cu-Li合金，通过少量的预变形，强度和延展性同时增强

IF 7 2区材料科学 Q1 MATERIALS SCIENCE, MULTIDISCIPLINARY

Materials Science and Engineering: A

Pub Date : 2026-01-19 DOI: 10.1016/j.msea.2026.149807

Fengjiao Niu , Haiyang Liu , Ruyu Cheng , Haoran Yang , Yixuan Hao , XiuBo Yang , Yajie Guo

The microstructure evolution and mechanical properties of a new Al-3.2Cu-0.9Li-0.4 Mg (wt.%) alloy with a moderate Cu/Li ratio of 3.5:1 under T8 treatment (incorporating 6 % pre-deformation followed by artificial aging) were systematically investigated. Compared to the T6 condition (direct artificial aging), the T8-treated alloy achieved a simultaneous enhancement in strength and elongation. Quantitative analysis of strengthening mechanisms reveals that precipitation strengthening provides the dominant contribution, which is significantly enhanced in the T8 state due to a refined and homogeneous distribution of T₁ (Al₂CuLi) and δ′/θ'/δ′ (Al₂Cu/Al₃Li/Al₂Cu) composite phases, promoted by the high-density dislocations from pre-deformation. This pre-deformation also facilitates the morphological transition of S phase (Al₂CuMg) from rod-like to lath-like and substantially narrows the grain boundary precipitate-free zones (PFZs) from 324 nm to 50 nm. The strengthening calculations further confirm the auxiliary roles of grain boundary and dislocation strengthening, while the contribution from solid solution strengthening remains comparable between the T6 and T8 states. These microstructural optimizations enhance intragranular strength and alleviate grain boundary brittleness, ultimately resulting in a 16 % increase in yield strength, a 12 % increase in tensile strength, and a 15 % improvement in elongation.

系统研究了Cu/Li比为3.5:1的Al-3.2Cu-0.9Li-0.4 Mg （wt.%）新型合金在T8处理（预变形6%后人工时效）下的组织演变和力学性能。与T6条件（直接人工时效）相比，t8处理的合金在强度和伸长率方面同时得到了提高。强化机制的定量分析表明，析出强化起主导作用，在T8状态下，由于预变形引起的高密度位错促进了T1 （Al2CuLi）和δ '/ θ'/δ ' （Al2Cu/Al3Li/Al2Cu）复合相的细化和均匀分布，强化作用显著增强。这种预变形还促进了S相（Al2CuMg）从棒状到板状的形态转变，并使晶界无析出带（PFZs）从324 nm大幅缩小到50 nm。强化计算进一步证实了晶界强化和位错强化的辅助作用，而固溶体强化的贡献在T6和T8状态之间保持相当。这些微观结构优化提高了晶内强度，缓解了晶界脆性，最终使屈服强度提高16%，抗拉强度提高12%，伸长率提高15%。

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引用次数: 0

Effect of annealing temperature on thermal expansion and cryogenic mechanical properties of low-thermal-expansion Co22.2Cr6.2Fe48.8Ni17.8Cu5.0 medium-entropy alloy 退火温度对低热膨胀Co22.2Cr6.2Fe48.8Ni17.8Cu5.0中熵合金热膨胀和低温力学性能的影响

IF 7 2区材料科学 Q1 MATERIALS SCIENCE, MULTIDISCIPLINARY

Materials Science and Engineering: A

Pub Date : 2026-01-19 DOI: 10.1016/j.msea.2026.149811

Wooyoung Lee , Munsu Choi , Sungwook Kim , Dae-Kyeom Kim , Myungsuk Song , Taek-Soo Kim , Jungwan Lee , Hyoung Seop Kim , Hyunjoo Choi , Soo-Hyun Joo

A low-thermal-expansion Co_22.2Cr_6.2Fe_48.8Ni_17.8Cu_5.0 medium-entropy alloy was fabricated, and its microstructure, cryogenic mechanical behavior, and magnetic properties were systematically investigated. While the alloy had a single-phase FCC structure for all the annealing temperatures considered—600, 800, and 1000 °C—its microstructural evolution varied with the annealing temperature, exhibiting recovery (600 °C), partial recrystallization (800 °C), and full recrystallization (1000 °C). The 600 °C specimen exhibited an anomalously higher elongation than the 800 °C specimen in tensile tests conducted at −196 °C, which could be attributed to the much higher transformation-induced plasticity in the former. For all the annealing temperatures, the coefficient of thermal expansion (CTE) was below 5 × 10⁻⁶ K⁻¹, and hence less than the CTE of Super Invar alloys. The saturation magnetization of all specimens was relatively stable between 50 K and 300 K, and the spontaneous volume magnetostriction and saturation magnetization had a proportional relationship, consistent with Masumoto's model. However, measured magnetic moments were considerably lower than those predicted by the Slater–Pauling curve, possibly because of magnetic dilution from antiferromagnetic Cr and nonmagnetic Cu. These findings advance the understanding of magnetic and thermal behavior of low-CTE complex concentrated alloys and point to the need for a design pathway for Invar-like high-performance materials.

制备了低热膨胀Co22.2Cr6.2Fe48.8Ni17.8Cu5.0中熵合金，并对其显微组织、低温力学行为和磁性能进行了系统研究。该合金在600、800和1000℃的退火温度下均为单相FCC组织，其显微组织演变随退火温度的变化而变化，表现为恢复（600℃）、部分再结晶（800℃）和完全再结晶（1000℃）。在- 196°C下进行的拉伸试验中，600°C的试样比800°C的试样表现出异常高的伸长率，这可能是由于前者具有更高的相变诱导塑性。在所有退火温度下，合金的热膨胀系数（CTE）均小于5 × 10−6 K−1，因此低于Super Invar合金的CTE。各试样的饱和磁化强度在50 ~ 300 K之间相对稳定，自发体积磁致伸缩与饱和磁化强度成正比关系，符合Masumoto模型。然而，测量到的磁矩比Slater-Pauling曲线预测的要低得多，可能是由于反铁磁性Cr和非磁性Cu的磁稀释。这些发现促进了对低cte复杂浓缩合金的磁性和热行为的理解，并指出需要设计类似invar的高性能材料。

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引用次数: 0

Towards power device packaging: Development of Cu-Au 10min direct bonding to replace sintered Ag paste using high interface density surface activation layers 面向功率器件封装：开发Cu-Au 10min直接键合技术，利用高界面密度表面活化层取代烧结银浆

IF 7 2区材料科学 Q1 MATERIALS SCIENCE, MULTIDISCIPLINARY

Materials Science and Engineering: A

Pub Date : 2026-01-19 DOI: 10.1016/j.msea.2026.149812

Ze-Hao Zhao , Wei Wu , Ming Liang , Jia-Hao Liu , Li-Yin Gao , Hao Zhang , Zhi-Quan Liu

The interconnection reliability between power semiconductor chips and substrates is a key bottleneck limiting the performance of wide-bandgap SiC devices. Although mainstream Ag particle sintering achieves high bonding strength, it suffers from high material costs, dimensional control and Ag-induced reliability issues. To address these limitations, this study proposes a direct bonding process with surface activated coatings, enabling efficient, high-strength direct diffusion bonding with nanoscale grooved Au plated SiC chips. To highlight the effect of microstructural regulation of the activated layer, three microstructure are compared—EP-NT Cu (electropolished Cu with high interface density) and EP-FG Cu (electropolished Cu with medium interface density), and EP-CG Cu (electropolished Cu with low interface density). Results show that the EP-NT Cu substrate bonds with Ni/Au layers upon SiC chips at 280 °C, 20 MPa under nitrogen atmosphere for 10 min, achieving a average shear strength of 83.9 MPa, which is much higher than 47.3 MPa (EP-CG Cu) and 73.8 MPa (EP-FG Cu). Detailed interfacial observation was conducted, almost 200 nm Cu₃Au phase were formed at the pore-free interface, indicating sufficient Cu-Au atomic interdiffusion. This technology provides a low-cost, high-reliability solution for high-density, high-reliability interconnection of power semiconductor chips.

功率半导体芯片与衬底之间的互连可靠性是制约宽带隙SiC器件性能的关键瓶颈。虽然主流的银颗粒烧结具有较高的结合强度，但存在材料成本高、尺寸控制和银引起的可靠性问题。为了解决这些限制，本研究提出了一种表面活化涂层的直接键合工艺，实现了纳米级沟槽镀金SiC芯片的高效、高强度直接扩散键合。为了突出活化层的微观结构调节作用，比较了ep - nt Cu（高界面密度电抛光铜）、EP-FG Cu（中等界面密度电抛光铜）和EP-CG Cu（低界面密度电抛光铜）三种微观结构。结果表明：在280℃、20 MPa、氮气气氛下，EP-NT Cu衬底与SiC芯片上的Ni/Au层结合10 min，平均剪切强度为83.9 MPa，远高于EP-CG Cu的47.3 MPa和EP-FG Cu的73.8 MPa；对界面进行了详细的观察，在无孔界面处形成了近200 nm的Cu3Au相，表明Cu-Au原子间有充分的相互扩散。该技术为功率半导体芯片的高密度、高可靠性互连提供了低成本、高可靠性的解决方案。

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引用次数: 0

New insight into impact toughness and crack resistance of Al-Li alloys: Precipitate evolution and dynamic analysis Al-Li合金冲击韧性和抗裂性能的新认识：析出相演变和动态分析

IF 7 2区材料科学 Q1 MATERIALS SCIENCE, MULTIDISCIPLINARY

Materials Science and Engineering: A

Pub Date : 2026-01-17 DOI: 10.1016/j.msea.2026.149740

Bo Ma, Fangzhou Qi, Youjie Guo, Yangyang Xu, Liang Zhang, Xuanxi Xu, Qi Li, Shen Zhang, Quande Li, Xin Tong, Guohua Wu

This study systematically investigates the effect of Li content on the microstructural evolution and dynamic fracture behavior under impact loading of cast Al-Li alloys. A Split Hopkinson Pressure Bar (SHPB) system was employed to obtain dynamic load-displacement curves, and the resistance to crack initiation and propagation was quantified using dynamic J-R integral analysis. With increasing Li content, significant grain coarsening, δ′ (Al₃Li) precipitate growth, and a faster rate of precipitate-free zone (PFZ) widening synergistically reduce the plastic deformation capacity. This reduction impairs the dissipation of plastic strain and accelerates crack propagation, ultimately leading to a degradation in impact toughness. High-Li alloys exhibit lower absorbed impact energy and transition from mixed cleavage-ductile (low-Li alloys) to predominantly intergranular brittle fracture. Dynamic J-R curve analysis demonstrates that increasing Li content not only decreases crack growth resistance but also accelerates unstable crack propagation by enlarging the crack tip plastic zone, thereby promoting the onset of crack instability. This study is expected to provide a novel perspective on the crack resistance of cast Al-Li alloys under impact loading by revealing the intricate relationships among microstructural evolution, absorbed impact energy, and crack propagation behavior.

本研究系统地研究了Li含量对铸铝锂合金冲击载荷下显微组织演变和动态断裂行为的影响。采用分离式霍普金森压杆（Split Hopkinson Pressure Bar， SHPB）系统获得了动态载荷-位移曲线，并采用动态J-R积分分析量化了其抗裂纹萌生和扩展能力。随着Li含量的增加，晶粒明显粗化，δ ' （Al3Li）析出物生长，无析出区（PFZ）扩大速度加快，共同降低了塑性变形能力。这种减少损害了塑性应变的耗散，加速了裂纹的扩展，最终导致冲击韧性的退化。高锂合金表现出较低的冲击吸收能和由解理-韧性混合断裂（低锂合金）向主要的晶间脆性断裂转变。动态J-R曲线分析表明，增加Li含量不仅降低了裂纹扩展阻力，而且通过扩大裂纹尖端塑性区加速了不稳定裂纹扩展，从而促进了裂纹不稳定的发生。本研究揭示了铸铝锂合金在冲击载荷下的组织演变、吸收的冲击能和裂纹扩展行为之间的复杂关系，为研究铸铝锂合金的抗裂性能提供了新的视角。

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引用次数: 0

Design and synergistic strengthening mechanisms of high strength-toughness Fe-Al-Ta alloy with multi-scale architecture 高强度韧性多尺度结构Fe-Al-Ta合金设计及协同强化机理

IF 7 2区材料科学 Q1 MATERIALS SCIENCE, MULTIDISCIPLINARY

Materials Science and Engineering: A

Pub Date : 2026-01-16 DOI: 10.1016/j.msea.2026.149780

Hongding Wang , Binbin Zhao , Yangcong Xiao , Ning Guo , Qian Meng , Jinyuan Ma , Peiqing La

Fe-Al intermetallic compounds exhibit high specific strength and stiffness, excellent resistance to hot corrosion and erosion, and superior high-temperature oxidation resistance. To address the challenge of balancing strength and ductility in Fe-Al intermetallic compounds, the Fe-Al-Ta eutectic alloys with varying Ta contents were designed and synthesized by the Thermite Self-Propagating High-Temperature Synthesis (SHS) method. The findings indicate that changes in Ta content significantly alter the morphology of the second phase in the alloy. Notably, at a Ta content of 20 wt%, fine and uniformly distributed anomalous eutectic particles substantially enhance the alloy's strength and toughness simultaneously. The SHS method, characterized by high reaction temperatures and rapid cooling rates, facilitates the formation of the desired nanocrystalline structure within the Fe₃Al(Ta) matrix phase. This nanocrystalline Fe₃Al(Ta) structure, combined with micron-sized anomalous eutectic Fe₂Ta(Al) particles, forms a micro-nano composite structure. During deformation, the synergistic interaction of this micro-nano structure enables the alloy to achieve high strength while maintaining good plasticity and toughness. The research reveals that the formation of anomalous eutectic Fe₂Ta(Al) particles stems from the remelting of regular eutectic lamellae. The favorable strength and toughness are attributed to grain nanocrystallization, multi-level heterogeneous deformation-induced strengthening, and precipitation strengthening provided by the anomalous eutectic particles.

Fe-Al金属间化合物具有较高的比强度和刚度，优异的抗热腐蚀和侵蚀性能，以及优异的高温抗氧化性能。为了解决Fe-Al金属间化合物在强度和延展性上的平衡问题，采用铝热剂自传播高温合成（SHS）方法设计并合成了不同Ta含量的Fe-Al-Ta共晶合金。结果表明，Ta含量的变化显著改变了合金中第二相的形貌。当Ta含量为20 wt%时，细小且分布均匀的异常共晶颗粒显著提高了合金的强度和韧性。SHS方法具有反应温度高、冷却速度快的特点，有利于在Fe3Al（Ta）基体相内形成所需的纳米晶结构。这种纳米晶Fe3Al（Ta）结构与微米尺寸的反常共晶Fe2Ta（Al）颗粒结合，形成微纳复合结构。在变形过程中，这种微纳结构的协同作用使合金在保持良好塑性和韧性的同时获得高强度。研究表明，异常共晶Fe2Ta（Al）颗粒的形成源于正常共晶片的重熔。晶粒的纳米化、多级非均相变形强化和异常共晶颗粒的析出强化是合金具有良好的强度和韧性的主要原因。

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引用次数: 0

HIP effect on the crack initiation and propagation of HCF for a nickel-based single crystal superalloy at 850 °C 850℃高温下HIP对镍基单晶高温合金HCF裂纹萌生和扩展的影响

IF 7 2区材料科学 Q1 MATERIALS SCIENCE, MULTIDISCIPLINARY

Materials Science and Engineering: A

Pub Date : 2026-01-16 DOI: 10.1016/j.msea.2026.149798

Siliang He , Longfei Li , Kuo Yin , Song Lu , Yunsong Zhao , Jian Zhang , Jonathan Cormier , Qiang Feng

Micropores, carbides and residual eutectics within interdendritic (ID) regions of the nickel-based single crystal (SX) superalloys can initiate microcracks during fatigue, thereby reducing fatigue life. Thus, controlling these microstructural features is critical for enhancing the high-cycle fatigue (HCF) properties of nickel-based SX superalloys at high temperature. In this study, the samples with different microstructures in the ID regions, achieved through various HIP and heat treatment schemes, were subjected to HCF tests at 850 °C/± 650 MPa, f = 30 Hz. The findings suggest that large micropores of non-HIP samples in the ID regions can easily become the crack initiation site during fatigue. HIP treatment decreased the size and volume fraction of micropores and changed crack initiation sites to oxidized carbides or surface oxides in the HIP-treated samples, thereby increasing fatigue rupture life. Furthermore, the crack initiation site in the HIP-treated sample with fewer carbides was found to be surface oxides, leading to longer fatigue rupture lives with nearly one order of magnitude than that of non-HIP samples. This study reveals the crack initiation and propagation mechanism by HIP treatment during fatigue, and improves the high-temperature HCF properties of nickel-based SX superalloys.

在镍基单晶高温合金的枝晶间区（ID）内的微孔、碳化物和残余共晶会在疲劳过程中引发微裂纹，从而降低疲劳寿命。因此，控制这些微观组织特征是提高镍基SX高温合金高温高周疲劳性能的关键。在本研究中，通过各种HIP和热处理方案获得的ID区域具有不同组织的样品进行了850°C/±650 MPa， f = 30 Hz的HCF测试。研究结果表明，在疲劳过程中，非热挤压试样的内径区较大的微孔很容易成为裂纹起裂点。HIP处理降低了微孔的尺寸和体积分数，使裂纹萌生部位转变为氧化碳化物或表面氧化物，从而提高了疲劳断裂寿命。此外，在含有较少碳化物的热处理样品中，发现裂纹起裂部位是表面氧化物，导致疲劳断裂寿命比非热处理样品长近一个数量级。本研究揭示了HIP处理在疲劳过程中的裂纹萌生和扩展机制，提高了镍基SX高温合金的高温HCF性能。

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引用次数: 0

Modulating thermal stability and deformation mechanisms in a CoCrNi medium-entropy alloy via hot and cold rolling 冷轧调节CoCrNi中熵合金的热稳定性和变形机制

IF 7 2区材料科学 Q1 MATERIALS SCIENCE, MULTIDISCIPLINARY

Materials Science and Engineering: A

Pub Date : 2026-01-16 DOI: 10.1016/j.msea.2026.149790

Hui Tao , Yong Pang , Rui Zhou , Huizhong Li , Yanlin Jia , Xiaopeng Liang

The thermo-mechanical processing of CoCrNi medium-entropy alloy was investigated by comparing two distinct routes: direct hot rolling (HR) and hot-plus-cold rolling (HCR), designed to produce initial states with low and high stored energy, respectively. The HR process yielded a thermally stable microstructure with low initial stored energy, retaining hardness and strength up to 700 °C. This stability is underpinned by sustained Twinning-Induced Plasticity (TWIP) activity across all tested conditions. Conversely, the high-stored-energy HCR alloy displayed a complex, non-monotonic annealing response. An anomalous strengthening effect was observed upon annealing at 550 °C, accompanied by a severe loss of ductility and work-hardening capacity. This behavior is attributed to recovery-induced strengthening, originating from local chemical composition fluctuations (specifically atomic clustering) at the high density of crystal defects introduced by cold rolling. This atomic clustering effectively pins the deformation substructure, inhibiting twinning and promoting a transition to localized planar slip and premature failure. At higher temperatures (≥650 °C), extensive recrystallization eliminates the dense defect substructures, thereby “rejuvenating” the TWIP effect and restoring ductility. This study clarifies the competition between recovery-induced strengthening (mediated by atomic clustering), recrystallization, and the TWIP effect, demonstrating that controlling initial stored energy via direct hot rolling is a promising strategy for designing thermally stable alloys.

通过对比直接热轧（HR）和热冷加轧制（HCR）两种不同的工艺路线，研究了CoCrNi中熵合金的热-机械加工过程，这两种不同的工艺路线分别产生低和高储存能量的初始状态。HR工艺产生了热稳定的微观结构，具有较低的初始储存能量，硬度和强度可保持到700°C。这种稳定性的基础是在所有测试条件下持续的孪生诱导可塑性（TWIP）活动。相反，高存储能量的HCR合金表现出复杂的非单调退火响应。在550℃退火时观察到异常强化效应，并伴有延展性和加工硬化能力的严重损失。这种行为归因于恢复诱导强化，源于冷轧引起的高密度晶体缺陷的局部化学成分波动（特别是原子聚集）。这种原子聚类有效地固定了变形子结构，抑制了孪晶，促进了向局部平面滑移和过早破坏的过渡。在较高的温度下（≥650℃），广泛的再结晶消除了致密的缺陷子结构，从而“恢复”TWIP效应并恢复延性。本研究阐明了恢复诱导强化（由原子聚类介导）、再结晶和TWIP效应之间的竞争，表明通过直接热轧控制初始存储能量是设计热稳定合金的一种有前途的策略。

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引用次数: 0

Tailoring Ni/Al content drives L12 precipitation achieving synergistic improvement of strength and ductility 调整Ni/Al含量驱动L12析出，从而协同提高强度和延展性

IF 7 2区材料科学 Q1 MATERIALS SCIENCE, MULTIDISCIPLINARY

Materials Science and Engineering: A

Pub Date : 2026-01-16 DOI: 10.1016/j.msea.2026.149802

Honghong Su , Yixi Hou , Jiatao Ye , Chen Sun , Cheng Jiang , Yaxi Ma , Xiaoran Zhao , Luyan Yang , Xiao Wei , Shengcheng Mao , Xiaodong Han

Precipitation strengthening via coherent L1₂ nanoprecipitates has emerged as an ideal strategy for designing high-performance materials. Most traditional design methods make it difficult to introduce a pure L1₂ structure into CoCrNi alloys by adding Al elements, which usually leads to a loss of ductility. This study designed an Al_0.3CoCr_0.9Ni_2.5 multi-principal element alloys through strategic Ni and Al compositional optimization, obtaining a high-density L1₂ nanoprecipitate structure that exhibits an exceptional combination of high strength and remarkable ductility. The preserved ductility stems from the synergistic interactions between stacking fault networks with Lomer-Cottrell (L-C) locks and deformation twinning. These mechanisms collectively induce a dynamic Hall-Petch effect and shorten the dislocation mean free path, thus enabling the high strain hardening capability. This innovative compositional design strategy demonstrates a viable pathway for designing high-performance precipitation-strengthened alloys.

通过相干L12纳米沉淀物的沉淀强化已经成为设计高性能材料的理想策略。大多数传统的设计方法很难通过添加Al元素来引入纯L12组织到CoCrNi合金中，这通常会导致延展性的损失。本研究通过对Ni和Al成分的战略性优化，设计了一种Al0.3CoCr0.9Ni2.5多主元素合金，获得了高密度的L12纳米沉淀结构，具有高强度和良好的延展性。保留的延性源于具有lomo - cottrell （L-C）锁的层错网络和变形孪晶之间的协同作用。这些机制共同诱导了动态Hall-Petch效应，缩短了位错的平均自由路径，从而实现了高应变硬化能力。这种创新的成分设计策略为设计高性能沉淀强化合金提供了一条可行的途径。

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引用次数: 0

Effect of heat treatments on microstructure and strengthening mechanisms of friction stir powder additive-manufactured Al-Zn-Mg-Cu aluminium alloy 热处理对搅拌摩擦粉添加剂制备Al-Zn-Mg-Cu铝合金组织及强化机理的影响

IF 7 2区材料科学 Q1 MATERIALS SCIENCE, MULTIDISCIPLINARY

Materials Science and Engineering: A

Pub Date : 2026-01-16 DOI: 10.1016/j.msea.2026.149801

Ramamoorthy Velayutham, Sudhir Behera, S. Sridharan, Jayaprakash Murugesan

Solid-state additive manufacturing is gaining attention for fabricating lightweight alloys with enhanced mechanical properties due to its low thermal input. In this work, a multilayer AA7075 (Al-Zn-Mg-Cu) alloy structure was developed using Friction Stir Powder Additive Manufacturing (FSPAM). A detailed study was then conducted to evaluate the influence of post-deposition heat treatments (T6 and T73) on the resulting microstructure, microhardness, and tensile behaviour of the as-deposited (AD) samples. The AD condition exhibited fine, equiaxed grains resulting from continuous dynamic recrystallization (CDRX). While the heat treatments had little effect on grain size, they significantly altered the nature and distribution of precipitates. After T6 treatment, fine η′ precipitates were observed within grains, along with coarser η precipitates at grain boundaries. The T6-treated sample achieved the highest ultimate tensile strength (UTS) of 560 MPa, with reduced ductility compared to both the AD and T73-treated specimens. Following the T73 heat treatment, the η′ precipitates underwent coarsening into the more stable η phase, which resulted in a reduction in UTS while enhancing ductility, as evidenced by the highest observed elongation among the tested conditions. Fractographic analysis of the as-deposited (AD) tensile specimens revealed features indicative of partial ductile fracture. In contrast, the T6-treated samples exhibited a reduced number of dimples containing fine precipitate particles, suggesting a more brittle fracture behaviour. The T73 specimens, however, displayed a higher density of larger dimples with coarser precipitates, consistent with the improved ductility resulting from the overaged microstructure. These findings demonstrate that the mechanical performance of FSPAM-processed aluminium alloys can be effectively tailored through the selection of appropriate post-heat treatment (T6 or T73), depending on the targeted application requirements.

由于其低热输入，固态增材制造在制造具有增强机械性能的轻质合金方面受到越来越多的关注。采用搅拌摩擦粉末增材制造技术（FSPAM）制备了多层AA7075 （Al-Zn-Mg-Cu）合金结构。然后进行了详细的研究，以评估沉积后热处理（T6和T73）对沉积态（AD）样品的显微组织、显微硬度和拉伸行为的影响。AD条件下，连续动态再结晶（CDRX）导致晶粒细小等轴。热处理对晶粒尺寸影响不大，但显著改变了析出相的性质和分布。T6处理后，晶粒内析出细小的η′相，晶界处析出较粗的η′相。与AD和t73处理的样品相比，t6处理的样品达到了最高的560 MPa的极限抗拉强度（UTS），但延展性降低。经过T73热处理后，η′析出相粗化为更稳定的η相，这导致了UTS的降低，同时提高了延展性，在测试条件中观察到最高的伸长率。对沉积态（AD）拉伸试样的断口分析显示出部分韧性断裂的特征。相比之下，经过t6处理的样品中含有细小沉淀颗粒的韧窝数量减少，表明其断裂行为更脆。然而，T73试样表现出更大的韧窝密度和更粗的析出相，这与过时效组织提高的延展性相一致。这些发现表明，fspam加工铝合金的机械性能可以根据目标应用要求，通过选择适当的后热处理（T6或T73）来有效地定制。

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