Intermetallics最新文献_第7页

Fe-based metallic glass coatings with suppressed cracks and enhanced wear resistance prepared by extreme high-speed laser cladding 通过极高速激光熔覆制备具有抑制裂纹和增强耐磨性的铁基金属玻璃镀层

IF 4.3 2区材料科学 Q2 CHEMISTRY, PHYSICAL

Intermetallics

Pub Date : 2024-10-03 DOI: 10.1016/j.intermet.2024.108517

Kai Wang , Cheng Zhang , Fengsheng Qu , Lin Liu , Xue Liu

Fe-based metallic glass (MG) coatings draw great attentions due to their excellent wear resistance. The recently developed extreme high-speed laser cladding (EHLC) provides a promising method for their fabrication but limited by the strong tendency to crack. Besides that, the deep insight into the structure evolution and the failure mechanism of the coating is still lacked. Thus, the understanding of the crack origin and the prevention of crack are of great importance. In the present work, Fe-Mo-Cr-Y-C-B MG coatings with adjustable glassy phase content were successfully fabricated by EHLC. The microstructure characterization of the coatings reveals that the cracks is main caused by the hard and brittle nanocrystalline phases precipitations of monoclinic Mo₁₂Fe₂₂C₁₀ and (Fe, Cr)₂₃C₆ carbides in the heat affected zone. Therefore, the cracking of the coatings can be effectively reduced by increasing the glassy phase content. Subsequently, the hardness distribution, wear performance and wear mechanism of the coatings were investigated. The results showed that increasing the glassy phase content can effectively achieve low wear rate. The prepared Fe-Mo-Cr-Y-C-B MG coatings exhibit abrasion loss as low as 3.54·10⁻⁶ mm³ (N m)⁻¹, which is an order of magnitude lower than that of the 45# steel substrate. The wear of the coatings is primarily attributed to the fatigue wear accompanied with slighting oxidative wear. By suppressing the brittle precipitated crystalline phases in the coating, the fatigue wear can be reduced and the wear resistance of the coatings can be improved. The present work provides insights into the crack prevention and were performance improvement of the Fe-based MG coatings prepared by EHLC.

铁基金属玻璃（MG）涂层因其出色的耐磨性而备受关注。最近发展起来的极高速激光熔覆（EHLC）为其制造提供了一种前景广阔的方法，但却受到了极易开裂的限制。此外，人们对涂层的结构演变和失效机理仍缺乏深入的了解。因此，了解裂纹的起源和防止裂纹的产生具有重要意义。本研究利用 EHLC 成功制备了玻璃相含量可调的 Fe-Mo-Cr-Y-C-B MG 涂层。涂层的微观结构表征表明，裂纹主要是由热影响区中单斜Mo12Fe22C10和（Fe, Cr）23C6碳化物的硬脆纳米晶相析出引起的。因此，通过增加玻璃相的含量可以有效减少涂层的开裂。随后，研究了涂层的硬度分布、磨损性能和磨损机理。结果表明，增加玻璃相含量可有效降低磨损率。制备的 Fe-Mo-Cr-Y-C-B MG 涂层的磨损损耗低至 3.54-10-6 mm3 (N m)-1，比 45# 钢基体的磨损损耗低一个数量级。涂层的磨损主要归因于疲劳磨损和轻微的氧化磨损。通过抑制涂层中的脆性析出结晶相，可以减少疲劳磨损，提高涂层的耐磨性。本研究为通过 EHLC 制备的铁基 MG 涂层的裂纹预防和性能改善提供了深入的见解。

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引用次数: 0

Unveiling the influence of zirconium on the corrosion behavior of Fe-36Ni Invar alloy 揭示锆对 Fe-36Ni 英达合金腐蚀行为的影响

IF 4.3 2区材料科学 Q2 CHEMISTRY, PHYSICAL

Intermetallics

Pub Date : 2024-10-02 DOI: 10.1016/j.intermet.2024.108519

Qi Wang , Yanwu Dong , Zhouhua Jiang , Zilin Yin , Yuning Wu , Haibiao Qing

The influence of zirconium (Zr) on the corrosion resistance of Fe-36Ni Invar alloy in a 3.5 wt% NaCl solution was systematically investigated. Results indicated that adding Zr promoted the formation of Zr-bearing intermetallic compounds (Ni₇Zr₂ and Ni₂Zr). The phases suppressed the grain growth and numerous dislocations were enriched around the Ni-Zr phases. Unfortunately, the incorporation of Zr into Fe-36Ni Invar alloy impaired corrosion resistance. The marked disparity in Volta potential between the Ni-Zr phases and the matrix signified the existence of micro-galvanic coupling, which caused the matrix to dissolve preferentially. Furthermore, the matrix around the Ni-Zr phases possessed high dislocation density, promoting the emergence of local galvanic corrosion. The introduction of Zr also decreased the protectiveness of the passive film, which was ascribed to the reduction of the thickness of the passive film and the beneficial oxide content in the passive film.

系统研究了锆 (Zr) 在 3.5 wt% 的 NaCl 溶液中对 Fe-36Ni 英达合金耐腐蚀性的影响。结果表明，锆的加入促进了含锆金属间化合物（Ni7Zr2 和 Ni2Zr）的形成。这些相抑制了晶粒的生长，并在 Ni-Zr 相周围富集了大量位错。遗憾的是，在 Fe-36Ni 英达合金中掺入 Zr 会影响耐腐蚀性。Ni-Zr 相与基体之间的伏特电位存在明显差异，这表明存在微电镀耦合，导致基体优先溶解。此外，Ni-Zr 相周围的基体具有较高的位错密度，促进了局部电化学腐蚀的出现。Zr 的引入也降低了被动膜的保护性，这归因于被动膜厚度的减少和被动膜中有益氧化物含量的降低。

引用次数: 0

Strength-ductility mechanism of combined heterostructured CoCrFeMnNi high-entropy alloy prepared by laser heat-treatment process 激光热处理工艺制备的组合异质结构钴铬铁镍高熵合金的强度-电导机制

IF 4.3 2区材料科学 Q2 CHEMISTRY, PHYSICAL

Intermetallics

Pub Date : 2024-10-01 DOI: 10.1016/j.intermet.2024.108511

Jie Chen , Chengchi Wang , Jianjun Ling , Pengfei Wang , Jingge Li , Haizhou Jin , Yu Cao

Two types of typical combined heterostructured CoCrFeMnNi high-entropy alloys with superior mechanical properties that evade the strength-ductility trade-off are fabricated using laser heat-treatment process. The lamellar grain structure with relatively high microhardness can hardly be observed due to the short time annealing at low temperature (873 K for 5 min) before laser scanning. The hetero-deformation induced strengthening, as well as the excellent deformation ability of the bottom hard region which can enhance the interaction between nanotwin-dislocation and maintains the large microhardness difference among the soft-hard layers, are the main factors that improve the yield strength of CoCrFeMnNi high-entropy alloy. Moreover, the combined heterostructured structure without lamellar deformed bands is demonstrated to have a relatively better uniform elongation, which is attributed to the stronger deformation ability of the non-recrystallized grains in the bottom hard region and the effective delay of the crack growth. Consequently, the combined heterostructured structure without lamellae is a promising way to simultaneously improve the strength and ductility, which can be efficiently prepared by the laser surface heat-treatment technique.

利用激光热处理工艺制造了两种典型的组合异质结构钴铬铁镍高熵合金，它们具有优异的机械性能，避免了强度-电导率之间的权衡。由于在激光扫描前进行了短时间的低温退火（873 K 5 分钟），因此很难观察到具有相对较高显微硬度的片状晶粒结构。异质变形诱导强化，以及底部硬质区域优异的变形能力可增强纳米孪晶-位错之间的相互作用，并保持软硬层之间较大的显微硬度差，是提高 CoCrFeMnNi 高熵合金屈服强度的主要因素。此外，无片状变形带的组合异质结构具有相对更好的均匀伸长率，这归因于底部硬质区域的非再结晶晶粒具有更强的变形能力，并有效延迟了裂纹的生长。因此，无薄片的组合异质结构是一种同时提高强度和延展性的有效方法，可通过激光表面热处理技术高效制备。

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引用次数: 0

Cu-bearing HHCCI interface combined with first principles calculation and corrosive wear resistance 含铜 HHCCI 接口与第一原理计算和耐腐蚀磨损性相结合

IF 4.3 2区材料科学 Q2 CHEMISTRY, PHYSICAL

Intermetallics

Pub Date : 2024-10-01 DOI: 10.1016/j.intermet.2024.108507

Liqiang Gong , Hejun Du , Rafik Absi , Longxiao Huang , Hanguang Fu

The corrosive wear resistance of copper-bearing HHCCI was tested through experiments and HRTEM, combined with first-principles calculations to study the atomic structure, interface fracture work, thermodynamic stability, electronic structure and bonding structure of six Fe₃Cr₄C₃(01

\overline{1}

0)/γ-Fe(101) interface models with different termination methods. The HRTEM results show that the interface formed by (01

\overline{1}

0) of M₇C₃-type carbide and (101) of the austenite matrix is a coherent interface. The first principles calculation results show that the interface formed by the Fe₃Cr₄C₃(01

\overline{1}

0)-Cr termination model and the γ-Fe (101)-2 termination model has the highest interface bonding strength. The Fe-end/7Fe-2 interface model is the most stable. Both the interfacial chemical energy and the interfacial elastic energy will affect the overall thermodynamic stability of the Fe₃Cr₄C₃(01

\overline{1}

0)/γ-Fe (101) interface. The fracture work of Fe₃Cr₄C₃(01

\overline{1}

0) and γ-Fe (101) is greater than the corresponding interface adhesion work. Moreover, the fracture work on each terminal end of M₇C₃ along the (01

\overline{1}

0) surface is higher than that on each terminal end of γ-Fe along the (101) surface. The failure of HHCCI during corrosive wear may mainly occur in the interface area or the side close to the γ-Fe matrix. The chemical bonds in the Fe-end/7Fe interface are mainly Fe-Fe metal bonds, Fe-Cr metal bonds and some Fe-C polar covalent bonds. The chemical bonds in the Cr-end/7Fe interface are mainly Cr-Fe metal bonds and some Cr-C polar covalent bonds. The chemical bonds in the C-end/7Fe interface are mainly composed of Cr-Fe metal bonds, C-Fe polar covalent bonds and part of C-Cr polar covalent bonds, as a result, each interface exhibits different corrosive wear resistance potentials.

通过实验和HRTEM测试了含铜HHCCI的耐腐蚀磨损性，并结合第一性原理计算研究了6种不同终止方法的Fe3Cr4C3(01 1‾ 0)/γ-Fe(101)界面模型的原子结构、界面断裂功、热力学稳定性、电子结构和成键结构。HRTEM 结果表明，M7C3 型碳化物（01 1‾ 0）与奥氏体基体（101）形成的界面是一个相干界面。第一性原理计算结果表明，Fe3Cr4C3（01 1‾ 0）-Cr终止模型和γ-Fe（101）-2终止模型形成的界面具有最高的界面结合强度。Fe-端/7Fe-2界面模型最为稳定。界面化学能和界面弹性能都会影响 Fe3Cr4C3(01 1‾ 0)/γ-Fe (101) 界面的整体热力学稳定性。Fe3Cr4C3(01 1‾0) 和 γ-Fe (101) 的断裂功大于相应的界面粘附功。此外，M7C3 沿（01 1‾ 0）表面各末端的断裂功均大于γ-Fe 沿（101）表面各末端的断裂功。在腐蚀磨损过程中，HHCCI 的失效可能主要发生在界面区域或靠近 γ-Fe 基体的一侧。Fe-端/7Fe界面中的化学键主要是Fe-Fe金属键、Fe-Cr金属键和一些Fe-C极性共价键。Cr-end/7Fe界面中的化学键主要是Cr-Fe金属键和一些Cr-C极性共价键。C端/7Fe界面的化学键主要由Cr-Fe金属键、C-Fe极性共价键和部分C-Cr极性共价键组成，因此，每个界面表现出不同的耐腐蚀磨损电位。

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引用次数: 0

Wear behavior of single-layer graphene oxide reinforced CoCrFeNiMn HEA coating by laser cladding 激光熔覆单层氧化石墨烯增强钴铬镍锰氢氧化钾涂层的磨损特性

IF 4.3 2区材料科学 Q2 CHEMISTRY, PHYSICAL

Intermetallics

Pub Date : 2024-09-30 DOI: 10.1016/j.intermet.2024.108512

Fangyan Luo , Shanshan Wang , Wenqing Shi , Zhengye Xiong , Jiang Huang

Graphene oxide (Go) has excellent mechanical properties, corrosion resistance, solid lubricant properties, and no biotoxicity. In this study, CoCrFeNiMn coating adding 2 wt% single layer of Go was prepared by laser cladding (LC) on the surface of Q235B. To explore the possibilities of Go as a reinforced powder. It was found that the alcohol stirring method could uniformly mix Go with HEA powder and would not destroy its microstructure. The main phase composition of the coatings does not change, but peaks of oxides and carbides were generated in the coatings. The carbide and oxide generation in the coating was demonstrated by EDS spot scanning. The addition of Go increased the microhardness of the coating by 51.33 %. The average coefficient of friction (COF) of the HEA/Go coating decreased by 16 %, the wear rate decreased by 82.05 %, and the wear weight loss decreased by 77.26 %. Improvement of the wear properties is mainly attributed to the generation of oxide film during friction.

氧化石墨烯（Go）具有优异的机械性能、耐腐蚀性、固体润滑剂性能和无生物毒性。本研究通过激光熔覆（LC）技术在 Q235B 表面制备了添加 2 wt% 单层 Go 的 CoCrFeNiMn 涂层。为了探索 Go 作为增强粉末的可能性。研究发现，酒精搅拌法能使 Go 与 HEA 粉末均匀混合，且不会破坏其微观结构。涂层的主要相组成没有变化，但涂层中产生了氧化物和碳化物峰。涂层中碳化物和氧化物的生成通过 EDS 点扫描得到了证实。添加 Go 后，涂层的显微硬度提高了 51.33%。HEA/Go 涂层的平均摩擦系数 (COF) 降低了 16%，磨损率降低了 82.05%，磨损失重降低了 77.26%。磨损性能的改善主要归功于摩擦过程中氧化膜的生成。

引用次数: 0

Effect of suction casting and thermomechanical processing on the microstructure and martensitic transformation of a TiNiCuNb shape memory alloy 吸铸和热机械加工对 TiNiCuNb 形状记忆合金微观结构和马氏体转变的影响

IF 4.3 2区材料科学 Q2 CHEMISTRY, PHYSICAL

Intermetallics

Pub Date : 2024-09-29 DOI: 10.1016/j.intermet.2024.108510

Jéssica Dornelas Silva , Mariana Lumi Ichihara Sado , Leandro Arruda Santos , Dilson Silva dos Santos , Vicente Tadeu Lopes Buono

TiNiCu-based superelastic alloys are promising for use as elastocaloric materials. In this study, we aim to produce a TiNiCuNb alloy with a refined microstructure, adequate Af, and latent heat for room-temperature application. For that, a Ti₄₈Ni₃₈Cu₁₀Nb₄ alloy was produced via arc melting followed by fast-cooling vacuum-suction casting (SC). Compared to the material that was only arc-melted, a refined and more uniform microstructure was obtained. This microstructure exhibited high stability during superelastic cycling and an Af much lower than room temperature. Further thermomechanical processing and heat-treatment (HT) were used to adjust the martensitic transformation (MT) critical temperatures and enthalpy. Increasing Af and enthalpy were observed with increasing HT temperatures. It was discussed that, besides the effect of the development of recovery/recrystallization mechanisms, the Nb content in the TiNi matrix could impact these properties. An Af close to, but smaller than room temperature, was obtained for the alloy heat-treated at 450 °C, with a MT enthalpy of 9.9 J/g.

钛镍铜基超弹性合金有望用作弹性材料。在本研究中，我们的目标是生产出一种具有精细微观结构、足够的Af和潜热的TiNiCuNb合金，以用于室温应用。为此，我们通过电弧熔化和快速冷却真空吸铸（SC）生产出了 Ti48Ni38Cu10Nb4 合金。与只进行电弧熔炼的材料相比，该合金获得了更精细、更均匀的微观结构。这种微观结构在超弹性循环过程中表现出很高的稳定性，其Af值远远低于室温。进一步的热机械加工和热处理（HT）用于调整马氏体转变（MT）临界温度和焓。随着热处理温度的升高，Af 和焓也随之增加。讨论认为，除了复原/再结晶机制的发展影响外，钛镍基体中的铌含量也会影响这些特性。在 450 °C下热处理的合金的Af接近室温，但小于室温，MT焓为9.9 J/g。

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引用次数: 0

Investigation on Microstucutres and properties of ion nitriding layer of Al0.5CoCrFeNiTi0.25 HEAs cladding coating Al0.5CoCrFeNiTi0.25 HEAs 覆层离子氮化层的微观力学性能研究

IF 4.3 2区材料科学 Q2 CHEMISTRY, PHYSICAL

Intermetallics

Pub Date : 2024-09-29 DOI: 10.1016/j.intermet.2024.108508

Meiyan Li , Yingjie Wang , Pu Li , Lixin Song , Lihu Guo , Bin Han

To investigate the effect of ion nitriding on the microstructures and properties of high entropy alloy coatings, the Al_0.5CoCrFeNiTi_0.25 high entropy alloy coating was fabricated via laser cladding and subsequently subjected to ion nitriding treatment. A comparative analysis were conducted to investigate the phase compositions, microstructures and properties of cladding coatings and ion nitriding layer. Furthermore the formation mechanism of the nitriding layer was studied. XRD results revealed that Al_0.5CoCrFeNiTi_0.25 HEA coatings consisted of duplex FCC and BCC phases, whereas the nitriding layer was composed of high-nitrogen FCC solid solutions and nitrides such as AlN, CrN, Fe₄N and TiN. Following ion nitriding, the surface morphology of nitriding layer presented “cauliflower-like” nitride particles, which became denser with the extended nitriding time. Notably, the microhardness of nitriding layer was approximately four times that of HEA coating, and the wear resistance and the corrosion resistance of cladding coating were improved significantly after ion nitriding. During ion nitriding process, N atoms reacted with the alloying elements to form nitrides, which preferentially deposited at grain boundaries and BCC phases and grew horizontally. As the deposition layer spread across the entire surface, the nitriding mechanism shifted from reaction -controlled to diffusion-controlled, with N atoms diffusing inward to form a diffusion layer with high nitrogen solid solutions. With the prolong of nitriding time from 1h to 12h, the thickness of the diffusion layer increased from 11.77 μm to 96.07 μm.

为了研究离子氮化对高熵合金镀层微观结构和性能的影响，通过激光熔覆制造了 Al0.5CoCrFeNiTi0.25 高熵合金镀层，随后对其进行了离子氮化处理。通过对比分析，研究了熔覆涂层和离子氮化层的相组成、微观结构和性能。此外，还研究了氮化层的形成机理。XRD 结果显示，Al0.5CoCrFeNiTi0.25 HEA 涂层由双相 FCC 和 BCC 相组成，而氮化层则由高氮 FCC 固溶体和氮化物（如 AlN、CrN、Fe4N 和 TiN）组成。离子氮化后，氮化层的表面形貌呈现出 "菜花状 "氮化物颗粒，随着氮化时间的延长，这些颗粒变得更加致密。值得注意的是，氮化层的显微硬度约为 HEA 涂层的四倍，而且离子氮化后堆焊涂层的耐磨性和耐腐蚀性也得到了显著改善。在离子氮化过程中，N 原子与合金元素反应形成氮化物，氮化物优先沉积在晶界和 BCC 相上并水平生长。当沉积层遍布整个表面时，氮化机理从反应控制转变为扩散控制，N 原子向内扩散，与高氮固溶体形成扩散层。随着氮化时间从 1 小时延长到 12 小时，扩散层的厚度从 11.77 μm 增加到 96.07 μm。

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引用次数: 0

Microstructure, mechanical and frictional properties of CrCoNi-xNb alloys prepared through powder metallurgy 通过粉末冶金制备的铬钴镍钴合金的微观结构、机械性能和摩擦性能

IF 4.3 2区材料科学 Q2 CHEMISTRY, PHYSICAL

Intermetallics

Pub Date : 2024-09-27 DOI: 10.1016/j.intermet.2024.108496

Lin Huang , Jingyu Zhang , Ke Xiong , Xiaofeng Wang , Wei Feng

Herein, CoCrNi-xNb (x = 0, 1, 3, 5, 7 and 9 wt%, referred to as 0Nb, 1Nb, 3Nb, 5Nb, 7Nb and 9Nb, respectively) alloys were prepared through mechanical alloying and spark plasma sintering techniques. The impact of Nb on the microstructure, mechanical and frictional properties of CoCrNi medium-entropy alloys were investigated. The evolution of the Laves phase (HCP) structure in alloy systems was well predicted using the

\overline{M d}

(the average energy level of d-orbitals) criterion. The results show that the structure changed from FCC single-phase (x = 0) to FCC + Laves biphase (x > 0). The alloy's hardness, YS and UTS increase as increase of Nb content increases the volume fraction of the Laves phase and reduces the FCC phase. The increase in hardness is beneficial for improving the wear resistance of the material. The wear mechanism of the alloy changes from abrasive to adhesive wear and then to oxidative wear, and it considerably improves the wear resistance of discs and pins. Thus, CoCrNi-xNb/GCr15 steel pairs are expected to achieve excellent tribological properties under high-temperature conditions. Among them, the mechanical and tribological properties of the CoCrNi-5Nb alloy are excellent. These results show that combining plasticity matrix and intermetallic compounds through powder metallurgy is a viable approach for designing high-strength wear-resistant alloys.

本文通过机械合金化和火花等离子烧结技术制备了 CoCrNi-xNb （x = 0、1、3、5、7 和 9 wt%，分别称为 0Nb、1Nb、3Nb、5Nb、7Nb 和 9Nb）合金。研究了 Nb 对 CoCrNi 中熵合金的微观结构、机械性能和摩擦性能的影响。利用Md‾（d-轨道的平均能级）准则很好地预测了合金体系中拉维斯相（HCP）结构的演变。结果表明，合金结构从 FCC 单相（x = 0）转变为 FCC + Laves 双相（x > 0）。随着铌含量的增加，Laves 相的体积分数增加，而 FCC 相的体积分数减少，合金的硬度、YS 和 UTS 也随之增加。硬度的增加有利于提高材料的耐磨性。合金的磨损机理从磨料磨损变为粘着磨损，再变为氧化磨损，从而大大提高了盘和销钉的耐磨性。因此，CoCrNi-xNb/GCr15 钢对有望在高温条件下获得优异的摩擦学性能。其中，CoCrNi-5Nb 合金的机械性能和摩擦学性能都非常出色。这些结果表明，通过粉末冶金结合塑性基体和金属间化合物是设计高强度耐磨合金的可行方法。

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引用次数: 0

Simulation-guided design of novel precipitation-strengthened eutectic high entropy alloy 新型沉淀强化共晶高熵合金的模拟指导设计

IF 4.3 2区材料科学 Q2 CHEMISTRY, PHYSICAL

Intermetallics

Pub Date : 2024-09-26 DOI: 10.1016/j.intermet.2024.108501

Manish Kumar Singh , B. Nithin , Kesavan Ravi , M.R. Rahul

Eutectic high entropy alloys (EHEAs) with hard and ductile phases are promising for high-temperature applications. The mechanical properties of EHEAs can be improved by incorporating precipitates in the ductile phase. The study focuses on the CALPHAD-guided alloy design approach for developing EHEA with cuboidal L1₂ precipitates in the ductile phase. The newly designed alloy (Al_0.17CoCrFeNiTa_0.22) is subjected to a simulation-guided heat treatment cycle. The Al_0.17CoCrFeNiTa_0.22 alloy shows FCC phase with a needle-like Ta-rich precipitate at 12 h and Ni-Al-rich cuboidal precipitate at 24 h of heat treatment. The calculated entropy of mixing of cuboidal precipitate is higher than that of needle-like precipitate. The detailed TEM characterisation confirms the characteristics of precipitates and microstructural changes correlated with microhardness measurements. The study proposes a novel EHEA system with a nano-scale precipitation-strengthened FCC phase and eutectic colony.

具有硬质相和韧性相的共晶高熵合金（EHEAs）在高温应用中大有可为。通过在韧性相中加入析出物，可以改善 EHEA 的机械性能。本研究的重点是采用 CALPHAD 引导的合金设计方法，开发韧性相中含有立方体 L12 沉淀的 EHEA。对新设计的合金（Al0.17CoCrFeNiTa0.22）进行了模拟指导的热处理循环。Al0.17CoCrFeNiTa0.22 合金显示出 FCC 相，在热处理 12 小时后出现针状富含 Ta 的沉淀，在热处理 24 小时后出现富含 Ni-Al 的立方体沉淀。计算得出的立方体沉淀的混合熵高于针状沉淀。详细的 TEM 表征证实了析出物的特征以及与显微硬度测量结果相关的显微结构变化。该研究提出了一种具有纳米级沉淀强化催化裂化相和共晶菌落的新型 EHEA 系统。

引用次数: 0

The roles of loading rate and temperature during shear-band-to-crack transition (SCT) in bulk metallic glasses: A study of quasi-static and dynamic shearing performances at ambient and cryogenic temperatures 块状金属玻璃中剪切带到裂纹转变（SCT）过程中加载速率和温度的作用：常温和低温下的准静态和动态剪切性能研究

IF 4.3 2区材料科学 Q2 CHEMISTRY, PHYSICAL

Intermetallics

Pub Date : 2024-09-26 DOI: 10.1016/j.intermet.2024.108467

Ding Zhou , Bing Hou , Yaqi Lin , Bingjin Li , Tianyan Liu , Hongwei Qiao , Lei Sun , Pengzhou Li , Yulong Li

The concomitant of relatively ductile-like shear banding and brittle-like fracture in metallic glasses makes their failure origin, i.e., how shear bands developing into cracks, a concerned issue to reveal the unique properties of the amorphous metals. Such shear-band-to-crack transition (SCT) is prominently influenced by loading rate and temperature, whereas their roles are usually ambiguous. In this paper, serial quasi-static and dynamic tests at ambient and cryogenic temperatures were performed to clarify the roles of strain rate and temperature during SCT in a Zr-based bulk metallic glass (BMG) by an electronic testing machine and a modified split Hopkinson pressure bar (SHPB) system, respectively. Strain rates were set from 10⁻³ s⁻¹ to 10³ s⁻¹ and temperatures were set from 173 K to 293 K. In-situ and post-fracture SCT patterns have been captured by high-speed photographing and scan electronic microscopy (SEM), which show a strong relevance to shear-band decohesion. Comparisons between SCT patterns under various loading conditions have clarified that loading rate controls decohesion distribution while temperature controls decohesion resistance. A decohesion-tendency ratio of applied energy to critical decohesion resistance is established from an energy-based view, and rate and temperature dependence of the ratio is discussed to figure out how these two effects determining different decohesion behavior and subsequent SCT patterns in BMGs.

金属玻璃中同时存在相对韧性的剪切带和脆性的断裂，这使得它们的失效起源，即剪切带如何发展成裂纹，成为揭示非晶态金属独特性质的一个重要问题。这种剪切带到裂纹的转变（SCT）受到加载速率和温度的显著影响，而它们的作用通常是模糊的。本文通过电子试验机和改进的分体式霍普金森压力棒（SHPB）系统，分别在常温和低温下进行了一系列准静态和动态试验，以明确应变速率和温度在锆基块状金属玻璃（BMG）的 SCT 过程中的作用。通过高速摄影和扫描电子显微镜（SEM）捕捉到了原位和断裂后的 SCT 图样，这些图样显示出与剪切带脱粘密切相关。对各种加载条件下的 SCT 图样进行比较后发现，加载速率控制着脱粘分布，而温度则控制着脱粘阻力。从基于能量的观点出发，建立了应用能量与临界脱粘阻力的脱粘倾向比率，并讨论了该比率与加载速率和温度的关系，以弄清这两种效应如何决定 BMG 的不同脱粘行为和随后的 SCT 模式。

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引用次数: 0