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Rapid alloying of CoCrFeMnNi high-entropy alloy from elemental feedstock toward high-throughput synthesis

《机械工程前沿（英文）》 2023年 第18卷 第1期 doi: 10.1007/s11465-022-0727-x

摘要： High-entropy alloys (HEAs) are considered alternatives to traditional structural materials because of their superior mechanical, physical, and chemical properties. However, alloy composition combinations are too numerous to explore. Finding a rapid synthesis method to accelerate the development of HEA bulks is imperative. Existing in situ synthesis methods based on additive manufacturing are insufficient for efficiently controlling the uniformity and accuracy of components. In this work, laser powder bed fusion (L-PBF) is adopted for the in situ synthesis of equiatomic CoCrFeMnNi HEA from elemental powder mixtures. High composition accuracy is achieved in parallel with ensuring internal density. The L-PBF-based process parameters are optimized; and two different methods, namely, a multi-melting process and homogenization heat treatment, are adopted to address the problem of incompletely melted Cr particles in the single-melted samples. X-ray diffraction indicates that HEA microstructure can be obtained from elemental powders via L-PBF. In the triple-melted samples, a strong crystallographic texture can be observed through electron backscatter diffraction, with a maximum polar density of 9.92 and a high ultimate tensile strength (UTS) of (735.3 ± 14.1) MPa. The homogenization heat-treated samples appear more like coarse equiaxed grains, with a UTS of (650.8 ± 16.1) MPa and an elongation of (40.2% ± 1.3%). Cellular substructures are also observed in the triple-melted samples, but not in the homogenization heat-treated samples. The differences in mechanical properties primarily originate from the changes in strengthening mechanism. The even and flat fractographic morphologies of the homogenization heat-treated samples represent a more uniform internal microstructure that is different from the complex morphologies of the triple-melted samples. Relative to the multi-melted samples, the homogenization heat-treated samples exhibit better processability, with a smaller composition deviation, i.e., ≤ 0.32 at.%. The two methods presented in this study are expected to have considerable potential for developing HEAs with high composition accuracy and composition flexibility.

关键词： laser powder bed fusion (L-PBF)     in situ alloying     high-entropy alloys     heat treatment     rapid synthesis    

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High-entropy catalysts for electrochemical water-electrolysis of hydrogen evolution and oxygen evolution

《能源前沿（英文）》 doi: 10.1007/s11708-023-0892-6

摘要： High entropy materials (HEMs) have developed rapidly in the field of electrocatalytic water-electrolysis for oxygen evolution reaction (OER) and hydrogen evolution reaction (HER) due to their unique properties. In particular, HEM catalysts are composed of many elements. Therefore, they have rich active sites and enhanced entropy stability relative to single atoms. In this paper, the preparation strategies and applications of HEM catalysts in electrochemical water-electrolysis are reviewed to explore the stabilization of HEMs and their catalytic mechanisms as well as their application in support green hydrogen production. First, the concept and four characteristics of HEMs are introduced based on entropy and composition. Then, synthetic strategies of HEM catalysts are systematically reviewed in terms of the categories of bottom-up and top-down. The application of HEMs as catalysts for electrochemical water-electrolysis in recent years is emphatically discussed, and the mechanisms of improving the performance of electrocatalysis is expounded by combining theoretical calculation technology and ex-situ/in situ characterization experiments. Finally, the application prospect of HEMs is proposed to conquer the challenges in HEM catalyst fabrications and applications.

关键词： high-entropy     electrocatalysis     synthetic methods     water-electrolysis     hydrogen and oxygen evolutions    

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一种具有超高温工程应用潜力的氮化物增强NbMoTaWHfN难熔高熵合金 Article

万义兴, 程延海, Yongxiong Chen, Zhibin Zhang, Yanan Liu, Haijun Gong, Baolong Shen, Xiubing Liang

《工程（英文）》 2023年 第30卷 第11期   页码 110-120 doi: 10.1016/j.eng.2023.06.008

摘要：

Refractory high-entropy alloys (RHEAs) have promising applications as the new generation of high-temperature alloys in hypersonic vehicles, aero-engines, gas turbines, and nuclear power plants. This study focuses on the microstructures and mechanical properties of the NbMoTaW(HfN)x (x = 0, 0.3, 0.7, and 1.0) RHEAs. The alloys consist of multiple phases of body-centered cubic (BCC), hafnium nitride (HfN), or multicomponent nitride (MN) phases. As the x contents increase, the grain size becomes smaller, and the strength gradually increases. The compressive yield strengths of the NbMoTaWHfN RHEA at ambient temperature, 1000, 1400, and 1800 °C were found to be 1682, 1192, 792, and 288 MPa, respectively. The high-temperature strength of this alloy is an inspiring result that exceeds the high temperature and strength of most known alloys, including high-entropy alloys, refractory metals, and superalloys. The HfN phase has a significant effect on strengthening due to its high structural stability and sluggish grain coarsening, even at ultra-high temperatures. Its superior properties endow the NbMoTaWHfN RHEA with potential for a wide range of engineering applications at ultra-high temperatures. This work offers a strategy for the design of high-temperature alloys and proposes an ultra-high-temperature alloy with potential for future engineering applications.

关键词： Refractory high-entropy alloy     High temperature     Mechanical property     Microstructure     Strengthening mechanism    

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高熵合金材料研究进展与展望

李天昕,王书道,卢一平,曹志强 ,王同敏,李廷举

《中国工程科学》 2023年 第25卷 第3期   页码 170-181 doi: 10.15302/J-SSCAE-2023.03.016

摘要：

随着世界科技水平的快速发展以及国民经济建设对高性能合金材料的迫切需求，传统单一主元合金逐渐不能满足人们与日俱增的使役需求。高熵合金因其独特的物理、化学以及力学性能，极大地拓展了金属材料成分设计范围，有望在国防、航空、航天、海洋、核能、医疗、新能源等重大工程领域发挥重要作用。本文结合各领域对先进高熵合金材料的具体需求，梳理了高熵合金材料的特征和内涵，分析了高熵合金材料发展的整体形势与前景，厘清了国内外高熵合金的发展现状。在此基础上，指出了我国高熵合金领域存在的差距和不足，我国高熵合金部分基础原材料依赖进口，严重威胁产业链安全；高熵合金产学研用体系尚未健全，工业化应用方面的研发投入有待提高。针对上述问题，研究建议，加强高熵合金材料研发的顶层设计，完善产业政策；加强企业和科研机构的对接和沟通；完善高熵合金材料标准、测试、表征、评价体系；推进人才队伍建设；降低材料成本，打造高附加值产品，促进我国先进高熵合金材料产业朝着体系化、绿色化、高端化、智能化方向发展。

关键词： 高熵合金；新材料；有色金属；关键战略材料；结构材料；功能材料    

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High-order phase-field model with the local and second-order max-entropy approximants

Fatemeh AMIRI

《结构与土木工程前沿（英文）》 2019年 第13卷 第2期   页码 406-416 doi: 10.1007/s11709-018-0475-5

摘要： We approximate the fracture surface energy functional based on phase-field method with smooth local maximum entropy (LME) and second-order maximum entropy (SME) approximants. The higher-order continuity of the meshfree methods such as LME and SME approximants allows to directly solve the fourth-order phase-field equations without splitting the fourth-order differential equation into two second-order differential equations. We will first show that the crack surface functional can be captured more accurately in the fourth-order model with smooth approximants such as LME, SME and B-spline. Furthermore, smaller length scale parameter is needed for the fourth-order model to approximate the energy functional. We also study SME approximants and drive the formulations. The proposed meshfree fourth-order phase-field formulation show more stable results for SME compared to LME meshfree methods.

关键词： second-order maximum entropy     local maximum entropy     second- and fourth-order phase-field models     B-spline    

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高强度合金抗疲劳应用技术研究与发展

越振业

《中国工程科学》 2005年 第7卷 第3期   页码 90-94

摘要：

评述了超高强度钢、高强度A1合金和Ti合金表面完整性抗疲劳应用技术的研究和发展。高强度合金疲劳性能对应力集中敏感，不适当的加工工艺和切削热等造成的表面损伤和髙拉应力使其疲劳和应力腐蚀性能损失殆尽。先进的表面完整性加工尤其是表面改性可显著提高疲劳性能，如激光冲击使7475-T761拉-拉疲劳寿命提高约89%，7075-T6裂纹扩展速率降低到原来的1/1500;超声喷丸使超高强度钢低周疲劳强度提高约50%，Ti7A14Mo合金髙周疲劳强度提高约15%;表面超硬化可使Vasco X-2M齿轮钢接触疲劳寿命提高30～35倍等。

关键词： 高强度合金     表面完整性     激光冲击     表面超硬化    

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Principle of maximum entropy for reliability analysis in the design of machine components

Yimin ZHANG

《机械工程前沿（英文）》 2019年 第14卷 第1期   页码 21-32 doi: 10.1007/s11465-018-0512-z

摘要： We studied the reliability of machine components with parameters that follow an arbitrary statistical distribution using the principle of maximum entropy (PME). We used PME to select the statistical distribution that best fits the available information. We also established a probability density function (PDF) and a failure probability model for the parameters of mechanical components using the concept of entropy and the PME. We obtained the first four moments of the state function for reliability analysis and design. Furthermore, we attained an estimate of the PDF with the fewest human bias factors using the PME. This function was used to calculate the reliability of the machine components, including a connecting rod, a vehicle half-shaft, a front axle, a rear axle housing, and a leaf spring, which have parameters that typically follow a non-normal distribution. Simulations were conducted for comparison. This study provides a design methodology for the reliability of mechanical components for practical engineering projects.

关键词： machine components     reliability     arbitrary distribution parameter     principle of maximum entropy    

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Anodization of titanium alloys for orthopedic applications

Merve İzmir, Batur Ercan

《化学科学与工程前沿（英文）》 2019年 第13卷 第1期   页码 28-45 doi: 10.1007/s11705-018-1759-y

摘要：

In recent years, nanostructured oxide films on titanium alloy surfaces have gained significant interest due to their electrical, catalytic and biological properties. In literature, there is variety of different approaches to fabricate nanostructured oxide films. Among these methods, anodization technique, which allows fine-tuning of oxide film thickness, feature size, topography and chemistry, is one of the most popular approaches to fabricate nanostructured oxide films on titanium alloys, and it has been widely investigated for orthopedic applications. Briefly, anodization is the growth of a controlled oxide film on a metallic component attached to the anode of an electrochemical cell. This review provides an overview of the anodization technique to grow nanostructured oxide films on titanium and titanium alloys and summarizes the interactions between anodized titanium alloy surfaces with cells in terms of cellular adhesion, proliferation and differentiation. It will start with summarizing the mechanism of nanofeatured oxide fabrication on titanium alloys and then switch its focus on the latest findings for anodization of titanium alloys, including the use of fluoride free electrolytes and anodization of 3D titanium foams. The review will also highlight areas requiring further research to successfully translate anodized titanium alloys to clinics for orthopedic applications.

关键词： titanium alloys     anodization     biocompatibility     orthopedics    

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Properties of Ag-doped Bi-Sb alloys as thermoelectric conversion materials for solid state refrigeration

Wen XU, Laifeng LI, Rongjin HUANG, Min ZHOU, Liyun ZHENG, Linghui GONG, Chunmei SONG

《能源前沿（英文）》 2009年 第3卷 第1期   页码 90-93 doi: 10.1007/s11708-009-0005-1

摘要： The energy conversion properties of Bi-Sb system thermoelectric materials doped by Ag was investigated. Bi Sb Ag ( =0, 1, 2, 3, 4) alloys with Ag substitution for Sb were synthesized by mechanical alloying and then pressed under 5 GPa at 523 K for 30 min. The phase structure of the alloys was characterized by X-ray diffraction. The electric conductivities and the seebeck coefficients were measured at the temperature range of 80-300 K. The results reveal that the electric conductivities of the Ag-doped Bi-Sb alloys are highly improved. The power factor of Bi Sb Ag reaches a maximum value of 2.98×10 W/(K ?m) at 255 K, which is about three times that of the un-doped sample Bi Sb at the same temperature.

关键词： thermoelectric conversion materials     high-pressure sintering     thermoelectric properties    

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我国航空铝合金产业发展战略研究

熊柏青,闫宏伟,张永安,李志辉,李锡武

《中国工程科学》 2023年 第25卷 第1期   页码 88-95 doi: 10.15302/J-SSCAE-2023.01.005

摘要：

航空铝合金作为航空器机体结构中最重要的结构材料之一，是我国国防科技工业发展、现代化经济体系建设、深入实施制造强国战略的重要物质基础。当前国际上已发展形成高强高韧铝合金、高比强/高比模铝合金、含钪高性能铝合金等三类主要航空铝合金体系，新一代高性能合金研究、高灵活度制备加工以及数据驱动的高效合金设计是主要的发展趋势。当前我国航空铝合金产业与国际发达国家总体“并跑”、部分“跟跑”，特别是在日趋复杂的国际国内宏观形势下，发展机遇与挑战并存，自主创新能力难以支撑航空铝合金材料创新引领、部分品种材料及装备“卡脖子”问题突出、产品国际市场竞争力不足、测试和应用数据积累及过程管控等基础体系能力短板尚存等问题更为突出。需从航空铝合金材料竞争力提升、新材料研发先行、高效上下游合作研发、新材料应用推广、材料指标和应用指标评价体系建立等方面发力，提升我国航空铝合金产业创新发展水平。

关键词： 航空；铝合金；高强高韧；高比模量    

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Temperature effects of shape memory alloys (SMAs) in damage control design of steel portal frames

Xiaoqun LUO, Hanbin GE, Tsutomu USAMI

《结构与土木工程前沿（英文）》 2012年 第6卷 第4期   页码 348-357 doi: 10.1007/s11709-012-0176-4

摘要： The objective of the present study is to analytically investigate temperature effects of an axial-type seismic damper made of shape memory alloys (SMAs) equipped in steel frames. Based on a modified multilinear one dimensional constitutive model of SMAs, two types of SMAs are employed, which have different stress plateau and different stress growth rate with temperature increase. Temperature effects of SMA dampers on seismic performance upgrading are discussed in three aspects: different environment temperatures; rapid loading rate induced heat generation and different SMA fractions. The analysis indicates that the effect of environment temperature should be considered for the SMA damper in steel frames. However, the rapid loading rate induced heat generation has little adverse effect.

关键词： damage control design     shape memory alloy     temperature effect    

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Maximum entropy based finite element analysis of porous media

Emad NOROUZI, Hesam MOSLEMZADEH, Soheil MOHAMMADI

《结构与土木工程前沿（英文）》 2019年 第13卷 第2期   页码 364-379 doi: 10.1007/s11709-018-0470-x

摘要： The maximum entropy theory has been used in a wide variety of physical, mathematical and engineering applications in the past few years. However, its application in numerical methods, especially in developing new shape functions, has attracted much interest in recent years. These shape functions possess the potential for performing better than the conventional basis functions in problems with randomly generated coarse meshes. In this paper, the maximum entropy theory is adopted to spatially discretize the deformation variable of the governing coupled equations of porous media. This is in line with the well-known fact that higher-order shape functions can provide more stable solutions in porous problems. Some of the benchmark problems in deformable porous media are solved with the developed approach and the results are compared with available references.

关键词： maximum entropy FEM     fully coupled multi-phase system     porous media    

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Ni-Ti-Cu-V四元薄膜库中微观结构和相变的组合合成和高通量表征 Article

Naila M. Al Hasan, Huilong Hou, Suchismita Sarkar, Sigurd Thienhaus, Apurva Mehta, Alfred Ludwig, Ichiro Takeuchi

《工程（英文）》 2020年 第6卷 第6期   页码 637-643 doi: 10.1016/j.eng.2020.05.003

摘要：

过去70年来，基于Ni-Ti的形状记忆合金（shape memory alloy, SMA）已得到广泛使用，但是提高 其功能稳定性仍然是实现更稳健和更高级应用的关键。SMA因其能够通过可逆的马氏体转变来保 持加工后的形状而得名，它对成分的变化非常敏感。因此，用三元和四元元素合金化来微调SMA 的晶格参数和热滞，成为材料研究中的一个难题。组合材料科学允许从多种表征技术中简化合成 过程和数据管理。本研究采用磁控溅射的方法，在热氧化的硅晶片上制备了具有成分分布的Ni-TiCu-V薄膜库。使用高通量波长色散光谱、同步加速器X射线衍射和温度相关的电阻，测量研究并 确定了成分相关的相变温度和微观结构。在材料库的177种成分中，有32种成分具有形状记忆效应， 其中5种成分具有零或接近零的热滞效应。应用中，这些合金成分在给定工作温度范围内提供了选 择的灵活性。结合薄膜库的局部微观结构和组成，讨论了四元体系的相图和功能特性的相关性。 

关键词： Ni–Ti–Cu–V合金     组合材料科学     四元合金     形状记忆合金     薄膜库     弹性冷却     热弹性冷却     相变     高通量表征     属性映射     机器学习    

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Application of entropy-based fuzzy matter-element analysis in seepage monitoring of RCC dam

Chongshi GU, Zhijun ZHANG, Xin CAI, Yue HOU

《结构与土木工程前沿（英文）》 2011年 第5卷 第1期   页码 105-111 doi: 10.1007/s11709-010-0015-4

摘要： Taking account of the fuzzy results of the seepage monitoring analysis of roller compacted concrete (RCC) dam and uncertainties of the individual indicator evaluation, the fuzzy matter-element model of seepage monitoring of RCC dam analysis has been established with the use of the fuzzy matter-element analysis theory and the concept of euclid approach degree. The use of entropy theory can calculate the weighting factor through the disorder utility values of the information reflected by the data itself, which can effectively avoid the problems of weight distribution and uncertainties of subjective judgments of the seepage monitoring analysis of roller compacted concrete dam. And further the example shows that the analysis of entropy-based fuzzy matter-element analysis model of the seepage monitoring of roller compacted concrete dam is in accordance with the actual situation, which verifies the effectiveness of the method.

关键词： information entropy     fuzzy matter-element     roller compacted concrete (RCC) dam     seepage analysis    

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Flux-free brazing of Mg-containing aluminium alloys by means of cold spraying

BOBZIN Kirsten, ZHAO Lidong, ERNST Felix, RICHARDT Katharina

《机械工程前沿（英文）》 2008年 第3卷 第4期   页码 355-359 doi: 10.1007/s11465-008-0055-9

摘要： In the present study, AlSi12 and AlSi10Cu4 were deposited onto Mg-containing aluminium alloys 6063 and 5754 by cold spraying. The influences of the two brazing alloys and spray parameters on coating formation were investigated. The microstructure of the coatings was characterized. Some coated samples were heat-treated at 590°C and 560°C in air to investigate the effect of the rupture of oxide scales on the diffusion of elements during heat-treatment. Some coated samples were brazed under argon atmosphere without any fluxes. The results show that AlSi12 had much better deposition behaviour than AlSi10Cu4. Due to the rupture of oxide scales, Cu and Si diffused into the substrate and a metallurgical bond formed between the brazing alloys and the substrates during heat-treatment. The coated samples could be brazed without any fluxes. Because the oxide scales prevented the formation of a metallurgical bond locally, the brazed samples had relatively low shear strengths of up to 43 MPa.

关键词： diffusion     metallurgical     substrate     Mg-containing aluminium     spraying    

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标题 作者 时间 类型 操作

Rapid alloying of CoCrFeMnNi high-entropy alloy from elemental feedstock toward high-throughput synthesis

期刊论文

High-entropy catalysts for electrochemical water-electrolysis of hydrogen evolution and oxygen evolution

期刊论文

一种具有超高温工程应用潜力的氮化物增强NbMoTaWHfN难熔高熵合金

万义兴, 程延海, Yongxiong Chen, Zhibin Zhang, Yanan Liu, Haijun Gong, Baolong Shen, Xiubing Liang

期刊论文

高熵合金材料研究进展与展望

李天昕,王书道,卢一平,曹志强 ,王同敏,李廷举

期刊论文

High-order phase-field model with the local and second-order max-entropy approximants

Fatemeh AMIRI

期刊论文

高强度合金抗疲劳应用技术研究与发展

越振业

期刊论文

Principle of maximum entropy for reliability analysis in the design of machine components

Yimin ZHANG

期刊论文

Anodization of titanium alloys for orthopedic applications

Merve İzmir, Batur Ercan

期刊论文

Properties of Ag-doped Bi-Sb alloys as thermoelectric conversion materials for solid state refrigeration

Wen XU, Laifeng LI, Rongjin HUANG, Min ZHOU, Liyun ZHENG, Linghui GONG, Chunmei SONG

期刊论文

我国航空铝合金产业发展战略研究

熊柏青,闫宏伟,张永安,李志辉,李锡武

期刊论文

Temperature effects of shape memory alloys (SMAs) in damage control design of steel portal frames

Xiaoqun LUO, Hanbin GE, Tsutomu USAMI

期刊论文

Maximum entropy based finite element analysis of porous media

Emad NOROUZI, Hesam MOSLEMZADEH, Soheil MOHAMMADI

期刊论文

Ni-Ti-Cu-V四元薄膜库中微观结构和相变的组合合成和高通量表征

Naila M. Al Hasan, Huilong Hou, Suchismita Sarkar, Sigurd Thienhaus, Apurva Mehta, Alfred Ludwig, Ichiro Takeuchi

期刊论文

Application of entropy-based fuzzy matter-element analysis in seepage monitoring of RCC dam

Chongshi GU, Zhijun ZHANG, Xin CAI, Yue HOU

期刊论文

Flux-free brazing of Mg-containing aluminium alloys by means of cold spraying

BOBZIN Kirsten, ZHAO Lidong, ERNST Felix, RICHARDT Katharina

期刊论文