Intermetallics最新文献_第6页

Rapid TLPD bonding of highly reliable full (Cu,Ni)6Sn5 IMC micro-joints using Cu-8Ni substrate for power device packaging

IF 4.3 2区材料科学 Q2 CHEMISTRY, PHYSICAL

Intermetallics

Pub Date : 2025-01-29 DOI: 10.1016/j.intermet.2025.108675

Yanqing Lai , Gaosong Li , Meiping Liu , Shuai Zhang , Yuanyuan Qiao , Yuanwei Jia , Ning Zhao

The full intermetallic compound (IMC) micro-joints formed by transient liquid phase diffusion (TLPD) bonding technology are playing an increasingly key role in power device packaging. In this investigation, the highly reliable full (Cu,Ni)₆Sn₅ IMC micro-joints with Cu-8Ni as the substrates was rapidly fabricated. Replacing Cu with Cu-8Ni alloy as the substrate not only greatly accelerated the growth of fine (Cu,Ni)₆Sn₅ grains during bonding, but also completely suppressed the formation of brittle Cu₃Sn layer and Kirkendall voids during aging. The microstructure, elemental distribution, grain features, mechanical properties and fractural micromorphology of the full IMC micro-joints after bonding and aging were systematically investigated. Moreover, the refinement and rapid growth mechanism of the (Cu,Ni)₆Sn₅ IMC grains was discussed in detail. The obtained full IMC micro-joints only consisting of fine (Cu,Ni)₆Sn₅ grains presented an excellent thermostability. The shear strength of the full (Cu,Ni)₆Sn₅ micro-joints slightly dropped from 71.87 MPa before aging to 67.63 MPa after aging at 200 °C for 400 h. The highly reliable full (Cu,Ni)₆Sn₅ micro-joints with Cu-8Ni as the substrates obtained by TLPD bonding was proved to be an effective method, which could dramatically decrease bonding time and enhance the thermostability and reliability of the full IMC micro-joints in third-generation semiconductor power device packaging.

通过瞬态液相扩散（TLPD）键合技术形成的全金属间化合物（IMC）微接头在功率器件封装中发挥着越来越关键的作用。在这项研究中，以 Cu-8Ni 为基底的高可靠性全 (Cu,Ni)6Sn5 IMC 微连接被快速制造出来。以 Cu-8Ni 合金取代铜作为基材，不仅大大加快了接合过程中细小（Cu,Ni）6Sn5 晶粒的生长，而且完全抑制了老化过程中脆性 Cu3Sn 层和 Kirkendall 空洞的形成。我们系统地研究了全 IMC 微接头在键合和老化后的微观结构、元素分布、晶粒特征、力学性能和断口微观形态。此外，还详细讨论了（Cu,Ni）6Sn5 IMC 晶粒的细化和快速生长机制。仅由细小的（Cu,Ni）6Sn5 晶粒组成的全 IMC 微接合呈现出极佳的热稳定性。以 Cu-8Ni 为基底，通过 TLPD 键合获得的高可靠性全 (Cu,Ni)6Sn5 微连接被证明是一种有效的方法，可显著缩短键合时间，提高全 IMC 微连接在第三代半导体功率器件封装中的耐热性和可靠性。

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引用次数: 0

Structural-weakening mapping to seismic-like slip avalanches in bulk-metallic glasses 结构削弱映射到块状金属玻璃中的地震样滑移雪崩

IF 4.3 2区材料科学 Q2 CHEMISTRY, PHYSICAL

Intermetallics

Pub Date : 2025-01-29 DOI: 10.1016/j.intermet.2025.108674

Jiaojiao Li , Junwei Qiao , Yong Liu , Yunzhi Ma , Xijing Zhu , Junyuan Wang , Zhiqiang Zeng , Linzheng Ye , Huihu Lu , Karin A. Dahmen , Peter K. Liaw

“Smaller is softer” mainly refers to the reverse size dependence of plasticity for bulk-metallic glasses (BMGs). Here, we report experimental results showing that “flatter acts more ductile”. Specifically, by choosing low aspect ratios for the samples, like 1:2, in compression experiments it is possible to eliminate catastrophically large (system-spanning) slips that are often seen for BMG samples with large aspect ratios of 3:1, 2:1, and 1:1. Moreover, for BMG samples with an aspect ratio of 1:2, multiple parallel shear bands produce self-similar slip avalanches, whose size distribution follows the stress-integrated power-law exponent of around 1.0. This exponent value, agrees with the prediction of mean field theory for a near-zero structural-weakening factor, modeling ductile behavior. The absence of structural weakening for the aspect ratio of 1:2 suggests that this aspect ratio may be preferable for some applications where large slips are undesirable because they lead to jerky deformation behavior and are difficult to control.

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引用次数: 0

Microstructure and mechanical properties of CoCrNi/GH99 medium entropy alloy brazed joints: Formation of medium entropy brazing seam

IF 4.3 2区材料科学 Q2 CHEMISTRY, PHYSICAL

Intermetallics

Pub Date : 2025-01-28 DOI: 10.1016/j.intermet.2025.108680

X.C. Li , J. Sun , Y.Z. Liu , W. Fu , X.G. Song , S.R. Yang , F. Long , S.P. Hu

Brazing CoCrNi to GH99 is of great significance for manufacturing high-strength and lightweight structural components in thermal protection systems. BNi-5a amorphous filler was used to braze CoCrNi to GH99 in this study, and medium entropy brazing seams were obtained. The typical CoCrNi/BNi-5a/GH99 joint is composed of the brazing seam and diffusion zones on both sides of substrates. The main component of the brazing seam is a γ (Ni, Cr) solid solution, with CrB and borides on CoCrNi side and GH99 side, respectively. Increasing the brazing temperature and prolonging the holding time can promote atomic diffusion and form more precipitates in diffusion zones on both sides, but the microstructure of the joints tends to homogenize under excessively high temperature or longer holding time. The joints obtained at the parameter of 1210 °C/10 min reach the maximum shear strength of 557 MPa. The brazing seam has outstanding effects similar to those of medium and high entropy alloys, leading to excellent mechanical properties. Most joints exhibit a mixed mode of cleavage fracture and microvoid coalescence fracture, and fracture occurs at the brazing seam. EBSD analysis reveals that the deformation of CoCrNi base material is greater than that of the brazing seam after shear test. ∑3 twins and low-angle grain boundaries are formed in CoCrNi substrate, and cracks propagate along the grain boundaries in the brazing seam.

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引用次数: 0

First-order reversal curve analysis of rapid-solidified Co78Zr17B2Si1M2 (M= W, Cr, Mo) alloys 快速凝固的 Co78Zr17B2Si1M2（M= W、Cr、Mo）合金的一阶反向曲线分析

IF 4.3 2区材料科学 Q2 CHEMISTRY, PHYSICAL

Intermetallics

Pub Date : 2025-01-28 DOI: 10.1016/j.intermet.2025.108668

M. Molaahmadi, M. Tavoosi, A. Ghasemi

This research focuses on first-order reversal curve (FORC) analysis of rapid-solidified Co₇₈Zr₁₇B₂Si₁M₂ (M = W, Cr, Mo) alloys. In this regard, vacuum arc melting and melt-spinning techniques were used to prepare the initial samples and the annealing process was carried out at temperature range of 400–700 °C. The prepared samples were analyzed using X-ray diffractometer (XRD), field emission scanning electron microscopy (FESEM) and FORC analysis. Based on the obtained results from the FORC analysis, the structure of Co₇₈Zr₁₇B₂Si₁M₂ (M = W, Cr, Mo) alloys after melt spinning process was combination of Co₅Zr and amorphous phase. The optimum annealing temperature to achieve the best hard magnetic properties was shown to be 400 °C as a result of the formation of a single-phase compound of Co₅Zr. The alloy containing Cr showed the highest coercivity (about 4.6 kOe), and the maximum coercivity for samples containing Mo and W was estimated to be about 3.4 kOe and 3.2 kOe, respectively.

本研究的重点是对快速凝固的 Co78Zr17B2Si1M2（M = W、Cr、Mo）合金进行一阶反向曲线（FORC）分析。研究采用真空电弧熔炼和熔融纺丝技术制备初始样品，并在 400-700 °C 温度范围内进行退火处理。制备的样品使用 X 射线衍射仪（XRD）、场发射扫描电子显微镜（FESEM）和 FORC 分析仪进行分析。根据 FORC 分析的结果，Co78Zr17B2Si1M2（M = W、Cr、Mo）合金在熔融纺丝后的结构是 Co5Zr 和非晶相的组合。由于 Co5Zr 单相化合物的形成，获得最佳硬磁特性的最佳退火温度为 400 ℃。含有铬的合金显示出最高的矫顽力（约 4.6 kOe），而含有钼和钨的样品的最大矫顽力估计分别约为 3.4 kOe 和 3.2 kOe。

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引用次数: 0

Effect of preloading treatment on dynamic mechanical properties of TiZr-based bulk metallic glass composite

IF 4.3 2区材料科学 Q2 CHEMISTRY, PHYSICAL

Intermetallics

Pub Date : 2025-01-27 DOI: 10.1016/j.intermet.2025.108677

Huanqi Liu , Ziyan Zhao , Juan Mu , Zhengwang Zhu , Haifeng Zhang , Yandong Wang

Deformation-induced phase transformation behavior is beneficial for plasticity and work hardening ability of bulk metallic glass composites (BMGCs). In this study, the effects of preloading treatment on the microstructure and dynamic mechanical properties of a TiZr-based BMGC with deformation-induced phase transformation were systematically studied. The strength and impact absorption energy of the composite were improved after the preloading treatment. Under a pressure of 1000 MPa for 10 min, the composite exhibits the best dynamic mechanical properties. The composite has an impact absorption energy of 18.7 MJ m⁻³, 10 times that of the as-cast sample. These results are attributed to the preformation of martensite during the preloading treatment and increases in volume fraction and variant types of martensite during the final dynamic deformation process. Deformation-induced phase transformation can effectively release local stress concentration, refine β phase grains, promote formation of multiple shear bands, and ultimately lead to a significant improvement in impact absorption energy. This study provides a new approach for improved dynamic mechanical properties of BMGCs.

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引用次数: 0

Effect of Nb addition in novel amorphous/nanocrystalline Ti-Zr-Cu-Ni-Nb brazing fillers on improving microstructure and mechanical properties of TiAl alloy joints 在新型非晶/纳米晶 Ti-Zr-Cu-Ni-Nb 铜焊填料中添加 Nb 对改善 TiAl 合金接头微观结构和机械性能的影响

IF 4.3 2区材料科学 Q2 CHEMISTRY, PHYSICAL

Intermetallics

Pub Date : 2025-01-25 DOI: 10.1016/j.intermet.2025.108673

Huyang Li , Longchao Zhuo , Wei Guo , Shujie Pang , Xueyin Bai , Huaping Xiong , Tao Zhang

For high-strength brazing of TiAl alloys, novel amorphous/nanocrystalline Ti₄₅Zr₂₅Cu₁₅Ni₁₅, Ti₄₅Zr₂₅Cu₁₀Ni₁₅Nb₅, and Ti₄₅Zr₂₅Cu₁₀Ni₁₀Nb₁₀ (at%) alloys (denoted as Nb0, Nb5, and Nb10, respectively) were designed and synthesized in a melt-spun ribbon form as the brazing filler metals (BFMs). With the increase of Nb content in the Ti-Zr-Cu-Ni(-Nb) alloys, the glass-forming ability exhibited a decreasing trend, while continuous and flexible BFM ribbons with a thickness up to 40 μm could still be obtained since the amorphous phase serves as the matrix of the ribbons. The effect of Nb addition in Ti-Zr-Cu-Ni(-Nb) BFMs on the microstructure and mechanical properties of TiAl alloy joints was investigated. By using the Ti-Zr-Cu-Ni(-Nb) BFMs, the resultant joints brazed at 1223 K for 30 min exhibited the microstructure consisting of α2-Ti₃Al and (Ti, Zr)₂(Cu, Ni) as the matrix and different precipitated phases at the center of the braze zones. For the joints brazed with the Nb0 and Nb5 BFMs, the precipitated phases were α2-Ti₃Al + α-Ti with an island-like morphology. By contrast, in the joint brazed with the Nb10 BFM, the precipitated phases were the almost continuous B2 + O-Ti₂AlNb, and the fraction of the brittle (Ti, Zr)₂(Cu, Ni) phase was reduced. Due to the improved microstructure, by using the Nb10 amorphous/nanocrystalline BFM ribbon, high shear strength up to ∼236 MPa was achieved for the TiAl alloy joint brazed at the relatively-low brazing temperature. It is indicated that the addition of Nb in the Ti-based BFMs is effective in improving the microstructure and strength of the TiAl brazed joints.

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引用次数: 0

Enhancement of magnetocaloric effect by amorphous engineering in Er-Tm-Al-Cu-Ni-Ga high-entropy alloy 在 Er-Tm-Al-Cu-Ni-Ga 高熵合金中通过非晶工程增强磁致效应

IF 4.3 2区材料科学 Q2 CHEMISTRY, PHYSICAL

Intermetallics

Pub Date : 2025-01-24 DOI: 10.1016/j.intermet.2025.108682

Yang Pan , Chaofan Liu , Xinqi Zheng , Guyue Wang , Yawei Gao , Dingsong Wang , Jiawang Xu , Lei Xi , Hao Liu , Shanshan Zhen , Zixiao Zhang , Guangrui Zhang , Anxu Ma , Zhe Chen , He Huang , Yanfei Wu , Jingyan Zhang , Shouguo Wang , Baogen Shen

Bulk and ribbon Er₂Tm₂Al₄CuNiGa high-entropy-alloy (HEA) were successfully synthesized by arc-melting method and amorphous engineering, respectively. X-ray diffraction experiment (XRD), differential scanning calorimetry (DSC) traces and high resolution transmission electron microscope (HRTEM) indicate that bulk sample crystalizes in form of polycrystalline while ribbon sample is amorphous. By amorphous engineering, the magnetic transition temperature was reduced below liquid helium temperature and low-field magnetocaloric effect (MCE) was greatly enhanced. The magnetic ordering temperatures were determined as 4.5 K and ∼3.0 K for bulk and ribbon samples, respectively. The maximum value of magnetic entropy change increases from 2.7/6.7 J/kgK for bulk sample to 4.3/9.0 J/kgK for typical ribbon sample R52 under field changes of 0–1/0–2 T. Furthermore, ribbon samples show the characteristic of second order magnetic transition based on Arrott plots, indicating of good magnetic and thermal reversibility. The large low-field MCE of ribbon Er₂Tm₂Al₄CuNiGa HEA at liquid helium temperature indicates that amorphous engineering is an effective method to improve the performance of magnetic cooling materials.

分别采用电弧熔融法和非晶工程法成功合成了块状和带状 Er2Tm2Al4CuNiGa 高熵合金（HEA）。X 射线衍射实验（XRD）、差示扫描量热仪（DSC）和高分辨率透射电子显微镜（HRTEM）显示，块状样品以多晶体形式晶化，而带状样品则为非晶体。通过非晶工程，磁转变温度降低到液氦温度以下，低场磁致效应（MCE）大大增强。经测定，块状样品和带状样品的磁有序温度分别为 4.5 K 和 ∼3.0 K。在 0-1/0-2 T 的磁场变化下，典型带状样品 R52 的磁熵变化最大值从块状样品的 2.7/6.7 J/kgK 增加到 4.3/9.0 J/kgK。在液氦温度下，带状 Er2Tm2Al4CuNiGa HEA 的低场 MCE 很大，这表明非晶工程是提高磁制冷材料性能的有效方法。

{"title":"Enhancement of magnetocaloric effect by amorphous engineering in Er-Tm-Al-Cu-Ni-Ga high-entropy alloy","authors":"Yang Pan , Chaofan Liu , Xinqi Zheng , Guyue Wang , Yawei Gao , Dingsong Wang , Jiawang Xu , Lei Xi , Hao Liu , Shanshan Zhen , Zixiao Zhang , Guangrui Zhang , Anxu Ma , Zhe Chen , He Huang , Yanfei Wu , Jingyan Zhang , Shouguo Wang , Baogen Shen","doi":"10.1016/j.intermet.2025.108682","DOIUrl":"10.1016/j.intermet.2025.108682","url":null,"abstract":"<div><div>Bulk and ribbon Er<sub>2</sub>Tm<sub>2</sub>Al<sub>4</sub>CuNiGa high-entropy-alloy (HEA) were successfully synthesized by arc-melting method and amorphous engineering, respectively. X-ray diffraction experiment (XRD), differential scanning calorimetry (DSC) traces and high resolution transmission electron microscope (HRTEM) indicate that bulk sample crystalizes in form of polycrystalline while ribbon sample is amorphous. By amorphous engineering, the magnetic transition temperature was reduced below liquid helium temperature and low-field magnetocaloric effect (MCE) was greatly enhanced. The magnetic ordering temperatures were determined as 4.5 K and ∼3.0 K for bulk and ribbon samples, respectively. The maximum value of magnetic entropy change increases from 2.7/6.7 J/kgK for bulk sample to 4.3/9.0 J/kgK for typical ribbon sample R52 under field changes of 0–1/0–2 T. Furthermore, ribbon samples show the characteristic of second order magnetic transition based on Arrott plots, indicating of good magnetic and thermal reversibility. The large low-field MCE of ribbon Er<sub>2</sub>Tm<sub>2</sub>Al<sub>4</sub>CuNiGa HEA at liquid helium temperature indicates that amorphous engineering is an effective method to improve the performance of magnetic cooling materials.</div></div>","PeriodicalId":331,"journal":{"name":"Intermetallics","volume":"179 ","pages":"Article 108682"},"PeriodicalIF":4.3,"publicationDate":"2025-01-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143181219","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Optimized microstructure and improved magnetic properties of B-lean hot deformed Nd-Fe-B magnets by Ga doping 通过掺杂镓优化 B-lean 热变形钕铁硼磁体的微观结构并改善其磁性能

IF 4.3 2区材料科学 Q2 CHEMISTRY, PHYSICAL

Intermetallics

Pub Date : 2025-01-24 DOI: 10.1016/j.intermet.2025.108676

Jianming Li , Qingzheng Jiang , Weiguo Wei , Song Fu , Mengping Kan , Zixiang Mo

Ga doping is beneficial to enhance the magnetic properties of Nd-Fe-B magnets, but the role of Ga in B-lean hot-deformed Nd-Fe-B magnets is still not clear. In this paper, B-lean hot-deformed Nd-Fe-B magnets with varying Ga content were prepared using spark plasma sintering (SPS) technique, and the effect of Ga doping on the phase composition, magnetic properties and microstructure of hot-deformed magnets were systematically investigated. The results show that both the remanent magnetization and coercivity of the magnets show a tendency of increasing and then decreasing with the increase of Ga content. Excellent magnetic properties of J_r = 14.20 kGs, H_cj = 12.78 kOe, and (BH)_max = 45.14 MGOe were obtained for Nd_29.89Fe_balGa_0.84Co_5.93B_0.89 magnet. In B-lean hot-deformed magnets, the increase of Ga content is favorable to the formation of Nd₆₍Fe, Co)₁₃Ga phase, improving the continuity of the grain boundary phase and reducing the RE-rich agglomerated region, as well as facilitating the grain refinement.

{"title":"Optimized microstructure and improved magnetic properties of B-lean hot deformed Nd-Fe-B magnets by Ga doping","authors":"Jianming Li , Qingzheng Jiang , Weiguo Wei , Song Fu , Mengping Kan , Zixiang Mo","doi":"10.1016/j.intermet.2025.108676","DOIUrl":"10.1016/j.intermet.2025.108676","url":null,"abstract":"<div><div>Ga doping is beneficial to enhance the magnetic properties of Nd-Fe-B magnets, but the role of Ga in B-lean hot-deformed Nd-Fe-B magnets is still not clear. In this paper, B-lean hot-deformed Nd-Fe-B magnets with varying Ga content were prepared using spark plasma sintering (SPS) technique, and the effect of Ga doping on the phase composition, magnetic properties and microstructure of hot-deformed magnets were systematically investigated. The results show that both the remanent magnetization and coercivity of the magnets show a tendency of increasing and then decreasing with the increase of Ga content. Excellent magnetic properties of <em>J</em><sub>r</sub> = 14.20 kGs, <em>H</em><sub>cj</sub> = 12.78 kOe, and (<em>BH</em>)<sub>max</sub> = 45.14 MGOe were obtained for Nd<sub>29.89</sub>Fe<sub>bal</sub>Ga<sub>0.84</sub>Co<sub>5.93</sub>B<sub>0.89</sub> magnet. In B-lean hot-deformed magnets, the increase of Ga content is favorable to the formation of Nd<sub>6(</sub>Fe, Co)<sub>13</sub>Ga phase, improving the continuity of the grain boundary phase and reducing the RE-rich agglomerated region, as well as facilitating the grain refinement.</div></div>","PeriodicalId":331,"journal":{"name":"Intermetallics","volume":"179 ","pages":"Article 108676"},"PeriodicalIF":4.3,"publicationDate":"2025-01-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143182239","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Corrosion behavior of aged NiTi shape memory alloys

IF 4.3 2区材料科学 Q2 CHEMISTRY, PHYSICAL

Intermetallics

Pub Date : 2025-01-24 DOI: 10.1016/j.intermet.2025.108679

N. Loukil , B. Ben Fraj

The corrosion behavior of 55.89 wt% Ni-NiTi Shape Memory Alloy (SMA) when aged at two aging temperatures, namely 450 °C and 650 °C is deeply investigated. To this end, Open Circuit Potential (OCP) tests, linear and cyclic potentiodynamic polarizations as well as Electrochemical Impedance Spectroscopy (EIS) were performed in physiological solution 0.9 % NaCl.

The OCP measurements suggest that the aging temperature significantly affects the formation and stability of the passive oxide film on the NiTi surface. Potentiodynamic polarization results show that 450 °C aged NiTi exhibits the best corrosion resistance. Compared to the as-received NiTi alloy, the corrosion current density (j_corr) of the 450 °C aged NiTi decreases by around 87 %, while the 650 °C aged NiTi shows lower corrosion resistance, with j_corr decreasing by 21 %.

The lowest passive current density (i_p) for the 450 °C aged sample confirms its superior corrosion resistance compared to the other conditions. The higher impedance magnitude (Z′) for the 450 °C aged sample indicates a more protective passive layer. Cyclic voltammetry collectively demonstrates that aging at 450 °C significantly enhances the corrosion resistance of NiTi in a physiological environment. This improvement is primarily due to microstructural changes, including grain refinement and the formation of Ti₃Ni₄ precipitates, which contribute to the formation of a more protective passive film.

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引用次数: 0

Dual-phase lamellar structure achieving high strength and large ductility in a novel Co-free eutectic high-entropy alloy 在新型无钴共晶高熵合金中实现高强度和大延展性的双相层状结构

IF 4.3 2区材料科学 Q2 CHEMISTRY, PHYSICAL

Intermetallics

Pub Date : 2025-01-23 DOI: 10.1016/j.intermet.2025.108669

Cong Peng , Yuanping Yuan , Qingqing Pei , Shuai Xu , Yong Xu , Quan Zhou , Ganggang Ma , Peidong Huang , Xiangkui Liu

The design of high-performance eutectic high-entropy alloy (EHEA) is still a huge challenging in material fields. Here, we designed a dual-phase Ni₄₉Fe₂₀Al₁₇Cr₈V₆ eutectic high-entropy alloy that can be prepared by directly cast methods. The as-cast Ni₄₉Fe₂₀Al₁₇Cr₈V₆ EHEA comprises of alternating soft FCC/L1₂ and hard B2 nanolamellae, which is enriched in Fe, V, Cr elements and Ni, Al elements, respectively. Furthermore, a classical K-S orientation relationship can be established between FCC and B2 phases. Superior mechanical properties, i.e., a high yield strength of ∼790 MPa, an ultimate tensile strength of ∼1230 MPa and a large uniform elongation of ∼16.5 %, can be achieved in the as-cast Ni₄₉Fe₂₀Al₁₇Cr₈V₆ EHEA. Such excellent combination of high strength and ductility in the as-cast Ni₄₉Fe₂₀Al₁₇Cr₈V₆ EHEA mainly originates from the strong interaction of high-density dislocations in both FCC/L1₂ and B2 nanolamellae. Specifically, high-density dislocations can be effectively hindered by the phase interface between soft FCC and hard B2 lamellae, contributing a high strength. Moreover, dense L1₂ nanoprecipitates can also impede the slipping of profuse dislocations in the FCC nanolamellae, significantly enhancing the mechanical properties of the Ni₄₉Fe₂₀Al₁₇Cr₈V₆ EHEA. The result in this work provides a strong theoretical guidance for the alloy design of high-performance metals.

高性能共晶高熵合金（EHEA）的设计仍然是材料领域的巨大挑战。在此，我们设计了一种可通过直接铸造方法制备的双相 Ni49Fe20Al17Cr8V6 共晶高熵合金。铸造后的 Ni49Fe20Al17Cr8V6 EHEA 由软质 FCC/L12 和硬质 B2 纳米晶交替组成，分别富含铁、钒、铬元素和镍、铝元素。此外，FCC 和 B2 相之间还可以建立经典的 K-S 取向关系。铸造后的 Ni49Fe20Al17Cr8V6 EHEA 具有优异的机械性能，即屈服强度高达 790 兆帕，极限拉伸强度高达 1230 兆帕，均匀伸长率高达 16.5%。铸态 Ni49Fe20Al17Cr8V6 EHEA 高强度和延展性的完美结合主要源于 FCC/L12 和 B2 纳米小室中高密度位错的强相互作用。具体来说，高密度位错可有效地受到软 FCC 和硬 B2 薄片之间相界面的阻碍，从而产生高强度。此外，致密的 L12 纳米沉淀物还能阻碍 FCC 纳米薄片中大量位错的滑动，从而显著提高 Ni49Fe20Al17Cr8V6 EHEA 的机械性能。这项研究成果为高性能金属的合金设计提供了有力的理论指导。

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引用次数: 0