Materials Science and Engineering: A最新文献_第2页

Plastic damage mechanism and grain orientation evolution along the thickness direction in heavy-walled submarine pipelines during the progressive forming process 渐进成型过程中厚壁海底管道的塑性损伤机制和沿厚度方向的晶粒取向演变

IF 6.1 2区材料科学 Q1 MATERIALS SCIENCE, MULTIDISCIPLINARY

Materials Science and Engineering: A

Pub Date : 2024-11-12 DOI: 10.1016/j.msea.2024.147524

Ling-zhi Xu , Gui-ying Qiao , Ying-long Ma , Yu Gu , Kai Xu , Xiao-wei Chen , Fu-ren Xiao

The progressive forming process (JCOE process) results in the creation of a high-strength submarine pipeline with substantial wall thickness. However, the accumulated of strain during the transverse forming process leads to increased disparities in the microstructure of layers with varying thicknesses, thereby impacting the longitudinal mechanical properties of the pipes. This investigation explores the combination of three-dimensional (3D) simulation and experimental methods allowed for comparison of how the JCOE process impacts the mechanisms of plastic damage and the evolution of longitudinal grain orientation in layers with varying thicknesses in pipes. It was revealed in the findings that the increase in accumulated strain led to a rise in dislocation density within the grain. This exacerbated dislocation pile-up at ferrite boundaries and ferrite/bainite interfaces and raised the level of plastic damage. A reduction in grain size enhanced the strain gradient in the surface layer, resulting in hindered advancement of plastic damage. From the 1/2-thickness layer towards the surface layer, the crystal orientation tended predominantly towards the [110] direction with the accumulation of strain. At a lower level of the accumulated plastic strain, the predominant orientation of the texture in the 1/2-thickness layer was directed towards the α-fibers. As the accumulated deformation progressed into the 1/4-thickness layer, the α-fiber transformed to a {001}<110> type texture under the combined effect of conjugated slip and cross-slip. The transformation of the {001}<110> type texture into the {112}<110> type texture ensued as the accumulated deformation progressed to the surface layer and tended to shift to the {111}<110> type texture. The results of this work guide methods to control the microstructure and properties of heavy-wall dual-phase steel submarine pipelines.

渐进成型工艺（JCOE 工艺）可制造出具有较大壁厚的高强度海底管道。然而，横向成型过程中累积的应变会导致不同厚度层的微观结构差异增大，从而影响管道的纵向机械性能。这项研究结合三维模拟和实验方法，比较了 JCOE 工艺如何影响塑性损伤机制以及管道中不同厚度层的纵向晶粒取向演变。研究结果表明，累积应变的增加导致晶粒内位错密度上升。这加剧了铁素体边界和铁素体/贝氏体界面的位错堆积，并提高了塑性破坏的程度。晶粒尺寸的减小增强了表层的应变梯度，从而阻碍了塑性破坏的发展。从 1/2厚度层向表层，随着应变的累积，晶体取向主要趋向于[110]方向。在较低的累积塑性应变水平上，1/2 厚层的纹理取向主要朝向 α 纤维。随着累积变形进入 1/4厚度层，在共轭滑移和交叉滑移的共同作用下，α纤维转变为{001}<110>型纹理。随着累积变形向表层发展，{001}<110>型纹理转变为{112}<110>型纹理，并有向{111}<110>型纹理转变的趋势。这项工作的结果为控制厚壁双相钢海底管道的微观结构和性能提供了指导方法。

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引用次数: 0

Microstructure and crack propagation behavior of 2195 Al–Li alloy with different orientations in the friction stir welding nugget zone 不同取向的 2195 Al-Li 合金在搅拌摩擦焊接金块区的显微组织和裂纹扩展行为

IF 6.1 2区材料科学 Q1 MATERIALS SCIENCE, MULTIDISCIPLINARY

Materials Science and Engineering: A

Pub Date : 2024-11-12 DOI: 10.1016/j.msea.2024.147537

Ke-jin Song , Yun-hua Wu , Pei-chen Liang , Xuesong Fu , Zheng-gen Hu , Guo-qing Chen , Wen-long Zhou

The 2195 Al–Li alloy is widely used in the aerospace field, where using friction stir welding technology can achieve lightweight and reduced wear designs for components. Fatigue failure, as one of the main modes of damage affecting the life and reliability of structural components, is particularly significant. This paper thoroughly explores the differences in microstructure and fatigue crack propagation behavior between the advancing side and retreating side of the friction stir welded joint in different sampling directions, providing a theoretical basis for enhancing the fatigue performance of friction stir welds. Characterization of the microstructure of the samples was performed using Electron Backscatter Diffraction (EBSD) and X-Ray Diffraction (XRD), and the fatigue properties were investigated using fatigue crack propagation rate curves and crack growth rate curves. The results indicate that the longitudinal base material grains tend to a fibrous structure, while the axial base material grains are distributed in a lamellar fashion. Compared to the advancing side of weld nugget zone, the retreating side of weld nugget zone has significantly reduced grain size and texture types. The fatigue performance of the retreating side of the weld nugget zone is superior to that of the advancing side, and the circumferential welds outperform the longitudinal welds in terms of fatigue performance.

2195 Al-Li 合金广泛应用于航空航天领域，利用搅拌摩擦焊接技术可以实现部件的轻量化和减少磨损设计。疲劳失效作为影响结构部件寿命和可靠性的主要损伤模式之一，其意义尤为重大。本文深入探讨了不同取样方向下搅拌摩擦焊接头前进侧和后退侧微观结构和疲劳裂纹扩展行为的差异，为提高搅拌摩擦焊的疲劳性能提供了理论依据。利用电子背散射衍射（EBSD）和 X 射线衍射（XRD）对样品的微观结构进行了表征，并利用疲劳裂纹扩展速率曲线和裂纹增长速率曲线对疲劳性能进行了研究。结果表明，纵向母材晶粒趋向于纤维状结构，而轴向母材晶粒则呈片状分布。与焊块区前进侧相比，焊块区后退侧的晶粒尺寸和纹理类型明显减少。焊块区后退侧的疲劳性能优于前进侧，圆周焊缝的疲劳性能优于纵向焊缝。

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引用次数: 0

Influence of solid solution time on microstructure and precipitation strengthening of novel maraging steels 固溶时间对新型马氏体时效钢微观结构和析出强化的影响

IF 6.1 2区材料科学 Q1 MATERIALS SCIENCE, MULTIDISCIPLINARY

Materials Science and Engineering: A

Pub Date : 2024-11-12 DOI: 10.1016/j.msea.2024.147535

T.Z. Xu , T. Wang , M.S. Wang , S. Zhang , C.H. Zhang , C.L. Wu , X.Y. Sun , H.T. Chen , J. Chen

Effective subsequent heat treatment is crucial for achieving the desired microstructure and excellent mechanical properties in laser-deposited high-performance maraging steel. In this paper, we systematically investigate the synergistic relationship and tuning mechanism of different solution treatment times on the microstructure-property synergy of new maraging steels fabricated using laser direct energy deposition (LDED). To determine the optimal heat treatment process, solution treatment was conducted at 840 °C for varying durations, followed by aging at 530 °C for 2 h to induce precipitation strengthening. The results indicate that after 2 h of solution treatment, the alloy exhibits optimal ductility with an elongation of 7.90 % ± 0.15 %, attributed to the refinement of the martensitic matrix and precipitated phases, along with the formation of a small amount of residual austenite. When the solution treatment time is extended to 4 h, the alloy achieves its highest tensile strength, reaching 1958 ± 24 MPa. However, the elongation decreases to 7.31 % ± 0.12 % due to the coarsening of the martensite and secondary phase particles. After 6 h of solution treatment, significant coarsening and aggregation of the martensite and Fe₂Mo intermetallic compounds markedly reduce the hardness, strength, and toughness of the alloy. By adjusting the solution treatment time, the size, morphology, and distribution of the martensitic matrix, Fe₂Mo, and nanoscale precipitated phases play a critical role in the strengthening and fracture processes. Therefore, optimizing the precipitation behavior of the martensitic matrix and Fe₂Mo intermetallic compounds through rational solution heat treatment is key to enhancing the mechanical properties of laser-deposited new maraging steels.

有效的后续热处理对于激光沉积高性能马氏体时效钢获得理想的微观组织和优异的机械性能至关重要。在本文中，我们系统地研究了不同固溶处理时间对使用激光直接能量沉积（LDED）制造的新型马氏体时效钢的微观结构-性能协同作用的协同关系和调整机制。为确定最佳热处理工艺，在 840 ℃ 下进行了不同持续时间的固溶处理，然后在 530 ℃ 下进行了 2 小时的时效处理，以诱导沉淀强化。结果表明，固溶处理 2 小时后，合金表现出最佳延展性，伸长率为 7.90 % ± 0.15 %，这归因于马氏体基体和析出相的细化，以及少量残余奥氏体的形成。当固溶处理时间延长到 4 小时时，合金的抗拉强度达到最高，为 1958 ± 24 兆帕。然而，由于马氏体和次生相颗粒的粗化，伸长率降至 7.31 % ± 0.12 %。经过 6 小时的固溶处理后，马氏体和 Fe2Mo 金属间化合物的显著粗化和聚集明显降低了合金的硬度、强度和韧性。通过调整固溶处理时间，马氏体基体、Fe2Mo 和纳米级析出相的尺寸、形态和分布在强化和断裂过程中起着至关重要的作用。因此，通过合理的固溶热处理优化马氏体基体和 Fe2Mo 金属间化合物的析出行为是提高激光沉积新型马氏体时效钢机械性能的关键。

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引用次数: 0

Size and microstructural factors affecting the micro-hole expansion ratio and fracture toughness of dual phase steel sheets 影响双相钢板微孔扩展率和断裂韧性的尺寸和微结构因素

IF 6.1 2区材料科学 Q1 MATERIALS SCIENCE, MULTIDISCIPLINARY

Materials Science and Engineering: A

Pub Date : 2024-11-12 DOI: 10.1016/j.msea.2024.147517

Soudip Basu , Balila Nagamani Jaya , Rohit Kumar Yadav , Sarbari Ganguly , Monojit Dutta

The microscopic hole expansion ratio (μHER) of a ferritic-martensitic (∼10 %) dual phase steel was measured using a novel in-situ scanning electron microscope based miniature hole expansion setup. The effect of extrinsic parameters such as specimen thickness and machining conditions, and intrinsic parameters such as hardness differential (ΔH =H_α'-H_α) between the soft ferrite matrix and hard martensite islands on μHER values was studied. The miniature HER setup allowed site-specific measurement of microscopic strain localizations in the DP microstructure through high resolution digital image correlation under the triaxial state of stress. The results from these experiments were juxtaposed against another triaxial state of stress ahead of a crack tip, in a fracture toughness (J_Ic) test using the single edge notched tensile (SENT) geometry for the same thickness and microstructural conditions of DP steel. It was found that the tempered DP specimen with lower ΔH resulted in a ∼45 % higher μHER as compared to the as-received DP600, although both specimens exhibited similar J_Ic values. This apparent discrepancy between the trends in μHER and J_Ic values was explained in terms of the differences in failure modes, triaxiality and plastic zone evolution in the two conditions.

使用基于微型孔膨胀装置的新型原位扫描电子显微镜测量了铁素体-马氏体（∼10 %）双相钢的微观孔膨胀率（μHER）。研究了试样厚度和加工条件等外在参数以及软铁素体基体和硬马氏体岛之间的硬度差 (ΔH =Hα'-Hα) 等内在参数对 μHER 值的影响。微型 HER 设置允许在三轴应力状态下通过高分辨率数字图像相关性对 DP 显微结构中的微观应变定位进行特定部位测量。在对相同厚度和微观结构条件的 DP 钢进行断裂韧性（JIc）测试时，采用单边缺口拉伸（SENT）几何形状，将这些实验结果与裂纹尖端前的另一种三轴应力状态并列。结果发现，与原样 DP600 相比，回火 DP 试样的 ΔH 较低，导致 μHER 高出 45%，尽管两种试样的 JIc 值相似。μHER和JIc值趋势之间的这种明显差异可以用两种条件下的失效模式、三轴性和塑性区演变的差异来解释。

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引用次数: 0

Synergistic strengthening mechanism of Mg and Si on Cu-Fe alloys with high strength and high conductivity 镁和硅对高强度、高导电性铜铁合金的协同强化机制

IF 6.1 2区材料科学 Q1 MATERIALS SCIENCE, MULTIDISCIPLINARY

Materials Science and Engineering: A

Pub Date : 2024-11-12 DOI: 10.1016/j.msea.2024.147534

Xiangyu Yu , Yanlong Xiang , Yuke Li , Junbin Cheng , Liuxiong Luo , Shen Gong , Zhou Li , Xiaojun Li , Qiru Wang

In this study, high strength and conductivity Cu-Fe-Si-Mg alloys were produced by casting and multi-stage thermos-mechanical treatment (MTT). The electrical conductivity, yield strength, tensile strength and elongation of the Cu-2.5Fe-0.1Si-0.15 Mg alloys were 68.23 %IACS, 653 MPa, 692 MPa and 4.35 %, respectively. The addition of Mg was beneficial to reduce the generalized planar fault energy and increase the density of substructure. Meanwhile, there was a tendency for Mg atoms to segregate at the interfacial region where the second phase met the copper. The segregation of Mg effectively inhibited the growth of precipitates. There was a dramatic improvement in the ability of the second phase to pin dislocations. The overall properties of the Cu-Fe alloys were excellent. The synergistic addition of Mg and Si significantly improved the mechanical properties of the alloys, but the electrical conductivity slightly declined.

本研究通过铸造和多级热机械处理（MTT）制备了高强度和导电性铜-铁-硅-镁合金。Cu-2.5Fe-0.1Si-0.15 Mg 合金的导电率、屈服强度、抗拉强度和伸长率分别为 68.23%IACS、653 兆帕、692 兆帕和 4.35%。镁的加入有利于降低广义平面断层能和增加下部结构的密度。同时，在第二相与铜的界面区域，镁原子有偏析的趋势。镁原子的偏析有效地抑制了析出物的生长。第二相针刺位错的能力显著提高。铜铁合金的整体性能非常出色。镁和硅的协同添加显著改善了合金的机械性能，但导电性略有下降。

引用次数: 0

Combined effects of carbon content and heat treatment on the high-temperature tensile performance of modified IN738 alloy processed by laser powder bed fusion 碳含量和热处理对激光粉末床熔融法加工的改性 IN738 合金高温拉伸性能的综合影响

IF 6.1 2区材料科学 Q1 MATERIALS SCIENCE, MULTIDISCIPLINARY

Materials Science and Engineering: A

Pub Date : 2024-11-12 DOI: 10.1016/j.msea.2024.147538

Han Zhang , Quanquan Han , Zhenhua Zhang , Yanzhen Liang , Liqiao Wang , Hongyuan Wan , Kaiju Lu , Zhengjiang Gao

Laser powder bed fusion (LPBF) is an advanced manufacturing technology used in processing nickel-based superalloys, notably for aero-engine components. One such material, the LPBF-fabricated IN738 superalloy, is prone to significant cracking issues. This study found that a change in carbon content (the optimal content of which was also determined) effectively mitigated the cracking. This study has systematically investigated the impact of different heat treatments on microstructural alterations and high-temperature tensile properties. The addition of 0.55 wt% of graphite proved effective in entirely inhibiting cracking in LPBF-fabricated IN738 specimens. Pre-alloyed IN738-M powder with the optimal carbon content was then produced and processed via LPBF to assess its formability. The as-built specimen revealed the presence of continuous carbides along the subgrain boundaries. Heat treatment promoted the transformation of substructured grains into recrystallised grains, accompanied by the precipitations of carbides and the γ′ phase; their morphologies were strongly determined by the solution treatment temperature. Differential scanning calorimetry measurements were employed to elucidate the differing microstructural states following distinct heat-treatment regimens. Under a 900 °C testing condition, stress-relieved (SR) specimens were found to exhibit superior performance, demonstrating an ultimate tensile stress (UTS) value of 843.6 MPa, a yield strength (YS) of 807.3 MPa and an elongation of 8.54 %. Notably, SR specimens also exhibited the highest UTS and YS values at 1000 °C, measuring 380.0 MPa and 346.5 MPa, respectively. This study's findings will furnish valuable insights for researchers who aim to enhance the high-temperature tensile performance of LPBF-fabricated nickel-based superalloys.

激光粉末床熔融（LPBF）是一种先进的制造技术，用于加工镍基超级合金，特别是航空发动机部件。其中一种材料，即 LPBF 制造的 IN738 超合金，容易出现严重的开裂问题。这项研究发现，改变碳含量（最佳含量也已确定）可有效缓解开裂问题。本研究系统地探讨了不同热处理对微观结构变化和高温拉伸性能的影响。事实证明，添加 0.55 wt% 的石墨可有效抑制 LPBF 制成的 IN738 试样的开裂。然后，生产出具有最佳碳含量的预合金 IN738-M 粉末，并通过 LPBF 进行加工，以评估其成型性。制成的试样显示，沿亚晶界存在连续的碳化物。热处理促进了亚结构晶粒向再结晶晶粒的转变，并伴随着碳化物和γ′相的析出；它们的形态在很大程度上取决于溶液处理温度。差示扫描量热测量法用于阐明不同热处理方案下的不同微观结构状态。在 900 °C 的测试条件下，应力释放（SR）试样表现出卓越的性能，其极限拉伸应力（UTS）值为 843.6 MPa，屈服强度（YS）为 807.3 MPa，伸长率为 8.54 %。值得注意的是，SR 试样在 1000 °C 时的 UTS 和 YS 值也是最高的，分别为 380.0 兆帕和 346.5 兆帕。这项研究的发现将为旨在提高 LPBF 制成的镍基超合金高温拉伸性能的研究人员提供宝贵的见解。

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引用次数: 0

Achieving strength-ductility synergy of ODS-FeCrAl alloys via heterostructured strategy 通过异质结构策略实现 ODS-FeCrAl 合金的强度-电导率协同效应

IF 6.1 2区材料科学 Q1 MATERIALS SCIENCE, MULTIDISCIPLINARY

Materials Science and Engineering: A

Pub Date : 2024-11-12 DOI: 10.1016/j.msea.2024.147536

Dingbo Sun, Zheng Lu, Xiaolong Li, Shang Gao, Hui Li

Oxide dispersion strengthened (ODS)-FeCrAl alloys are candidate structural materials for advanced nuclear reactor applications, which have excellent strength and radiation tolerance but low ductility. In this study, a novel ODS-FeCrAl heterostructured composite, reinforced with FCC-structured ODS-CoCrFeNiMn high-entropy particles, was prepared by using mechanical alloying and spark plasma sintering to achieve the strength-ductility synergy. The effect of different reinforcement contents (0, 10, 15 and 20 wt%, designated as RC-0, RC-10, RC-15, and RC-20, respectively) on the microstructure and mechanical properties of the composites was investigated. The results showed that the unreinforced reference alloy, RC-0, consists of BCC-structured ODS-FeCrAl matrix and high-density oxides. In the RC-10, RC-15, and RC-20 composites, in addition to the ODS-FeCrAl matrix and nanoscale oxides, FCC-structured ODS-CoCrFeNiMn high-entropy reinforcement with ultrafine grain size and FCC transition layer with gradient grain size are observed. As the reinforcement content increases, the thickness of transition region increases. The composites show an increase in ultimate compressive strength and compressive strain with increasing reinforcement content in the following order: 2951 MPa/33.6 %, 3169 MPa/40.0 %, 3290 MPa/43.2 %, and 3489 MPa/48.8 %. And the compressive yield strength exhibits an initial increase and subsequent decrease, i.e. 1523 MPa (RC-0), 1680 MPa (RC-10), 1635 MPa (RC-15), and 1355 MPa (RC-20), respectively. The increase in yield strength is mainly attributed to hetero-deformation induced (HDI) strengthening and reinforcement hardening. The improvement in ductility is mainly attributed to the HDI work hardening and the suppression of microcrack formation and propagation at prior powder boundaries.

氧化物弥散强化（ODS）-铁铬铝合金是先进核反应堆应用的候选结构材料，具有优异的强度和辐射耐受性，但延展性较低。本研究采用机械合金化和火花等离子烧结技术制备了一种新型 ODS-FeCrAl 异质结构复合材料，并用 FCC 结构的 ODS-CoCrFeNiMn 高熵颗粒进行了增强，以实现强度-韧性的协同作用。研究了不同增强含量（0、10、15 和 20 wt%，分别称为 RC-0、RC-10、RC-15 和 RC-20）对复合材料微观结构和力学性能的影响。结果表明，未增强的参考合金 RC-0 由 BCC 结构的 ODS-FeCrAl 基体和高密度氧化物组成。在 RC-10、RC-15 和 RC-20 复合材料中，除了 ODS-FeCrAl 基体和纳米级氧化物外，还观察到具有超细晶粒尺寸的 FCC 结构 ODS-CoCrFeNiMn 高熵增强层和具有梯度晶粒尺寸的 FCC 过渡层。随着增强层含量的增加，过渡区的厚度也随之增加。复合材料的极限抗压强度和抗压应变随着增强层含量的增加依次增加：2951 兆帕/33.6%、3169 兆帕/40.0%、3290 兆帕/43.2% 和 3489 兆帕/48.8%。而抗压屈服强度则呈现出先上升后下降的趋势，即分别为 1523 兆帕（RC-0）、1680 兆帕（RC-10）、1635 兆帕（RC-15）和 1355 兆帕（RC-20）。屈服强度的提高主要归因于异变形诱导（HDI）强化和钢筋硬化。延展性的提高主要归因于 HDI 加工硬化和抑制了粉末边界处微裂纹的形成和扩展。

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引用次数: 0

Tension-compression asymmetry and the grain-scale slip behavior in untextured Mg-10Gd-3Y-0.5Zr (wt.%) 无纹理 Mg-10Gd-3Y-0.5Zr（重量百分比）的拉伸-压缩不对称和晶粒尺度滑移行为

IF 6.1 2区材料科学 Q1 MATERIALS SCIENCE, MULTIDISCIPLINARY

Materials Science and Engineering: A

Pub Date : 2024-11-12 DOI: 10.1016/j.msea.2024.147533

Xianhua Zheng , Ran Ni , Zhiwei Jiang , Hao Zhou , Ying Zeng , Dongdi Yin

Mg-10Gd-3Y-0.5Zr (wt.%) is a recently developed high-performance cast Mg alloy with random texture. The present work found that both strength and ductility of this alloy were significantly larger for compression than that for tension, i.e. the mechanical properties exhibited tension-compression asymmetry (TCA), although no twins were observed. To understand this uncommon behavior, the relative activity of individual slip modes and slip-slip interactions during deformation were analyzed in detail at grain scale, based on quasi-in-situ experiments, combined with slip trace analysis and EBSD technique. Significantly asymmetric slip behavior was observed. Although basal slip always dominated for both tension and compression, the relative activity of pyramidal II <c+a> (PyrIICA) slip for tension was 2.6 times higher than that for compression. Statistical analysis of the angle between the active slip plane normal and the loading direction implied that the PyrIICA slip was more easily activated when the slip plane under tension. The asymmetric activity of PyrIICA slip was believed to contribute to the observed yield strength TCA. What’s more, almost all possible combinations of cross slip and slip transfer for total 30 slip systems were observed and analyzed in detail only during compression, while such behavior was not observed under tension. The strong slip-slip interactions induced by massive cross slips and effectively accommodated intergranular deformation by slip transfer were consistent with the well-balanced strain hardening, which resulted in improved ultimate strength and ductility for compression.

Mg-10Gd-3Y-0.5Zr (wt.%) 是最近开发的一种具有随机纹理的高性能铸造镁合金。目前的研究发现，这种合金的压缩强度和延展性都明显大于拉伸强度和延展性，即机械性能表现出拉伸-压缩不对称（TCA），尽管没有观察到孪晶。为了理解这种不常见的行为，我们以准原位实验为基础，结合滑移轨迹分析和 EBSD 技术，在晶粒尺度上详细分析了变形过程中单个滑移模式和滑移-滑移相互作用的相对活动。观察到了明显的非对称滑移行为。虽然在拉伸和压缩过程中，基底滑移始终占主导地位，但在拉伸过程中，金字塔 II <c+a>（PyrIICA）滑移的相对活性是压缩过程中的 2.6 倍。对活动滑移面法线与加载方向夹角的统计分析表明，当滑移面处于拉伸状态时，PyrIICA 滑移更容易被激活。PyrIICA 滑移的非对称活动被认为是导致观察到的屈服强度 TCA 的原因。此外，在总共 30 个滑移系统中，几乎所有可能的交叉滑移和滑移转移组合都只在压缩过程中被观察到并进行了详细分析，而在拉伸过程中却没有观察到这种行为。大量交叉滑移引起的强烈滑移-滑移相互作用，以及滑移转移有效容纳的晶间变形，与均衡的应变硬化相一致，从而提高了压缩极限强度和延展性。

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引用次数: 0

Exceptional tensile strength-ductility synergy in friction stir processed Mg-Y-Nd-Zr alloy achieved through bimodal grain size distribution 通过双峰晶粒尺寸分布实现摩擦搅拌加工 Mg-Y-Nd-Zr 合金卓越的拉伸强度和电导率协同效应

IF 6.1 2区材料科学 Q1 MATERIALS SCIENCE, MULTIDISCIPLINARY

Materials Science and Engineering: A

Pub Date : 2024-11-12 DOI: 10.1016/j.msea.2024.147521

Annayath Maqbool , Nadeem Fayaz Lone , Noor Zaman Khan , Arshad Noor Siddiquee , Daolun Chen

For advanced structural and functional applications, achieving a balanced strength-ductility trade-off is crucial. Nevertheless, the enhancement of strength often results in reduction of ductility, a phenomenon more pronounced in nano-grained materials. Although bimodal grain structures offer potential solution to address this issue, their realization generally involve complex processing steps. Herein, a bimodal grain structure was developed in Mg-Y-Nd-Zr alloy through Friction Stir Processing (FSP). The developed microstructure contains ultra-fine grains of about 2 μm interspersed within fine grains of ∼15 μm. The processed specimen displayed an enhanced tensile strength of 195 MPa, while simultaneously achieving an exceptional elongation of 31 %. These remarkable properties are attributed to the distinct bimodal grain structure, which effectively delays the onset of plastic instability, thereby enhancing strength, uniform elongation, and the rate of work hardening.

对于先进的结构和功能应用而言，实现强度和延展性的平衡权衡至关重要。然而，强度的提高往往会导致延展性的降低，这种现象在纳米晶粒材料中更为明显。虽然双峰晶粒结构为解决这一问题提供了潜在的解决方案，但其实现通常涉及复杂的加工步骤。本文通过摩擦搅拌加工（FSP）在 Mg-Y-Nd-Zr 合金中开发了一种双峰晶粒结构。所形成的微观结构包含约 2 μm 的超细晶粒，其中夹杂着 15 μm 的细晶粒。加工后的试样抗拉强度提高到了 195 兆帕，同时伸长率也达到了 31%。这些出色的性能归功于独特的双峰晶粒结构，它有效地延缓了塑性不稳定性的发生，从而提高了强度、均匀伸长率和加工硬化率。

引用次数: 0

Effect of aging temperature on the microstructural evolution and mechanical properties of 18Ni (200) maraging steel 时效温度对 18Ni (200) 马氏体时效钢微观结构演变和机械性能的影响

IF 6.1 2区材料科学 Q1 MATERIALS SCIENCE, MULTIDISCIPLINARY

Materials Science and Engineering: A

Pub Date : 2024-11-10 DOI: 10.1016/j.msea.2024.147497

Yujian Zhang, Yanmei Li, Xiangtao Deng

Herein, we used transmission electron microscopy (TEM), electron backscattering diffraction (EBSD), and X-ray diffractometry (XRD) to investigate the effects of different aging temperatures on reversed austenite and precipitates in 18Ni (200) maraging steel, as well as their evolving patterns of cryogenic toughness and strength. Aging at 510 °C was found to enhance cryogenic toughness at −196 °C and deliver peak strength, which is attributable to the significant aging-strengthening effect and the reversed austenite. Furthermore, this study investigated the factors that contribute to the formation and high stability of reversed austenite and quantitatively assessed the contributions of aging strengthening, dislocation strengthening, and grain-boundary strengthening to yield strength at various aging temperatures.

在此，我们使用透射电子显微镜（TEM）、电子反向散射衍射（EBSD）和 X 射线衍射仪（XRD）研究了不同时效温度对 18Ni (200) 马氏体时效钢中反转奥氏体和析出物的影响及其低温韧性和强度的演变规律。研究发现，510 °C的时效可提高-196 °C的低温韧性并达到峰值强度，这归因于显著的时效强化效应和反转奥氏体。此外，该研究还调查了反转奥氏体形成和高稳定性的因素，并定量评估了不同时效温度下时效强化、位错强化和晶界强化对屈服强度的贡献。

引用次数: 0