共查询到18条相似文献,搜索用时 78 毫秒
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王冬青 《中国材料科技与设备》2008,5(1):19-22
本文详细阐述了镁合金中长周期有序堆剁相的最新研究进展,对镁合金中长周期有序堆剁相的结构进行了系统的论述,展望了镁合金中的长周期有序堆剁结构的研究趋势。 相似文献
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高性能稀土镁合金的研究进展 总被引:3,自引:0,他引:3
随着近年来汽车等工业节能减排对更高性能轻质镁合金的迫切需求,镁合金在工业应用中展现出了很大的发展前途。稀土镁合金系由于具有高温强度高、优良抗蠕变性能及耐热性能以及良好的塑性和耐腐蚀性等高性能,已经成为越来越受到重视的镁合金系之一,并在航空航天、电子、汽车、通讯等领域得到了广泛应用。目前,国内外已开发了Mg-Gd、Mg-Y、Mg-Gd-Y、Mg-Y-Gd等一系列稀土镁合金。综述了高性能稀土镁合金的研究进展和应用现状,主要介绍了Mg-Y和Mg-Gd二元和多元合金系的研究开发及应用的新进展,以及含长周期堆垛有序结构(Long Period Stacking Ordered Structure,简称LPSO结构)的Mg-Y-Zn、Mg-Gd-Zn、Mg-Gd-Y-Zn、Mg-Y-Gd-Zn合金系的研究现状。最后,展望了高性能稀土镁合金的发展趋势。 相似文献
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分子离子渗氮过程中形成的Fe4N电子衍射花样。发现Fe4N具有长周期结构,这种长周期结构可看作是层错有序分布的密堆结构。 相似文献
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镁合金中的LPSO结构 总被引:1,自引:1,他引:0
详细描述了铁合金中的LPSO相的最新研究进展,系统总结了镁合金中的LPSO相的结构、微合金组元的化学成分,分析了微观形成过程与机制以及优异的力学性能,展望了镁合金中LPSO结构的研究趋势. 相似文献
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Interfacial dislocations dominated lateral growth of long-period stacking ordered phase in Mg alloys
Qianqian Jin Xiaohong Shao Shijian Zheng Yangtao Zhou Bo Zhang Xiuliang Ma 《材料科学技术学报》2021,61(2):114-118
Understanding the interface between strengthening precipitates and matrix in alloys, especially at the atomic level, is a critical issue for tailoring the precipitate strengthening to achieve desired mechanical properties. Using high-resolution scanning transmission electron microscopy, we here clarify the semicoherent interfaces between the matrix and long-period stacking ordered(LPSO) phases, including 18 R and 14 H, in Mg–Zn–Y alloys. The LPSO/Mg interface features the unique configuration of the Shockley partial dislocations, which produces a near zero macroscopic strain because the net Burgers vectors equal zero. The 18 R/Mg interface characterizes a dissociated structure that can be described as a narrow slab of 54 R. There are two dislocation arrays accompanied to the 18 R/54 R and 54 R/Mg interface, resulting a slight deviation(about 2.3°). The 14 R/Mg interface exhibits the dislocation pairs associated with solute atoms. We further evaluate the stability and morphology of the corresponding interfaces based on elastic interaction, via calculating the mutual strong interactions between dislocation arrays, as well as that between the dislocations and solute atoms. The synchronized migration of interfacial dislocations and solute atoms, like move-drag behavior, dominates the lateral growth of LPSO phases in Mg alloys. 相似文献
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铀铌合金作为一种重要的核工程材料,因其较高的密度、优异的耐蚀性能和良好的力学性能等特点,被广泛应用于核工业领域。铀铌合金受成分及热处理工艺影响显著,表现出复杂的相转变和组织结构特征,使得铀铌合金耐腐蚀性能及力学性能可在较大范围内获得调控。本文按照"成分/工艺-结构-性能"主线,综述了近年铀铌合金在结构、性能调控方面的研究进展,认为:低温时效机制和杂质控制技术仍是铀铌二元合金研究中需要重点关注的问题;高通量设计、制备及表征手段的出现,为未来铀铌多元合金结构及性能调控研究带来了新的机遇与挑战。 相似文献
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A hitherto unreported long-period stacking-ordered (LPSO) phase, designated 12R, was observed in a Mg80Ni5Y15 (at.%) alloy. Microstructure was investigated by electron diffraction and high-angle annular dark-field scanning transmission electron microscopy. Results show that the 12R has a trigonal lattice (a = b = 1.112 nm, c = 3.126 nm, α = β = 90°, and γ = 120°). Unit cell of the 12R is consisted of three ABCA-type building blocks and each building block contains dominant Ni6Y8-type building clusters. A sound structural model is proposed based on relative positions of Ni6Y8 clusters in neighboring building blocks. 相似文献
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采用高能球磨法和放电等离子体烧结(SPS)技术,以包含100%长周期堆垛有序结构(LPSO)相Mg85Zn6Y9镁合金为原料,通过将其球磨成纳米晶颗粒后与Mg-9Al-1Zn(AZ91)镁合金雾化颗粒进行机械混合,并在350℃烧结温度下成功制备出不同质量分数(0~30wt%)的LPSO相Mg85Zn6Y9颗粒增强AZ91复合材料(Mg85Zn6Y9/AZ91)。采用光学显微镜(OM)、SEM及TEM对Mg85Zn6Y9/AZ91复合材料的微观组织结构进行表征;采用XRD分析其固溶处理前后的相转变;与此同时对复合材料进行显微硬度与压缩试验,综合研究其微观组织与力学性能的关系。相关结果表明,Mg85Zn6Y9颗粒经3 h高能球磨后颗粒尺寸显著减小,硬度随晶粒细化而提升。Mg85Zn6Y9增强颗粒主要分布在AZ91基体颗粒边界处,随着Mg85Zn6Y9质量分数的增加,增强相颗粒有相互结合成连续网格状趋势。增强颗粒与基体界面处未见明显过渡层,基体界面处的β相经400℃×24 h固溶处理后进入基体,部分增强颗粒亦转变为Mg相。本实验条件下制备的最佳性能的20wt% Mg85Zn6Y9/AZ91复合材料经固溶处理后的室温屈服强度从200 MPa转变为230 MPa,屈服强度均较未添加Mg85Zn6Y9的AZ91镁合金有较大的提高。 相似文献
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The Mg–8Y–1Er–2Zn (wt.%) alloy with high strength, plasticity and heat-resistance was prepared by the hot extrusion technique and the following aging treatment. The microstructure and mechanical properties were investigated. The results show that long period stacking ordered (LPSO) phase is different from common inermetallics, and the former can be bent by plastic deformation and presents good combination with the Mg matrix. The good mechanical properties of as-extruded alloy are mainly attributed to the lamellar strips with 18R LPSO structure as well as the microstructure refinement. Aging treatment at 220 °C can further improve the strength but not at the expense of plasticity. The ultimate tensile strength (UTS) and elongation to failure (ε) of as-extruded alloy at peak hardness are 390 MPa and 18% at room temperature, and 322 MPa and 30% at 250 °C, respectively. The formation of fine α-Mg recrystallization grains with high number density of 14H LPSO structure is mainly responsible for the superior mechanical properties of extruded alloy after peak-aging. 相似文献
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引入共格析出相是强化合金的重要方式。近年来发现在BCC结构多主元合金中引入共格B2相可有效提升其力学性能,形成了一类重要的合金体系。本文综述了含BCC/B2共格结构多主元合金的研究现状,重点讨论这一系列新型合金在成分、组织形貌、结构稳定性以及力学性能等方面的特征,并指出此类合金在宽温域下强度较高、塑性因成分差异而不同的变化特点。目前,这类合金在高于500℃时的结构稳定性较差,无法满足工程应用的需求,而成分设计是解决此问题较为简单易行的方法。本文旨在为含BCC/B2共格结构多主元合金的设计提供参考。 相似文献