Design of Supevalloys using Nb

使用 Nb 的超级合金设计

• 批准号: 09450258
• 负责人: TAKEYAMA Masao
• 金额: $ 8.96万
• 依托单位: Tokyo Institute of Technology
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (B)
• 财政年份: 1997
• 资助国家: 日本
• 起止时间: 1997 至 1999
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-09450258/
• 关键词: Ni_3 Nb-S; Ni-Nb-M; Lattice misfit; Crystal structure; Misfit dislocation; Symmetry of crystal; Precipitation; Micrpstructure contral; 構造緩和; ミスフィット転位; 格子定数; Ni_3 Nb-S; Nib Nb sl-η; 一方向擬固; 結晶方位関係; Nb; 対称性

The intermetallic compound Ni_3Nb (δ) is of interest as a strengthener of Ni base alloys because of its phase stability up to the melting temperature. The crystal structure of the δ phase is ordered orthorhombic (DO_a structure), the lowest crystal symmetry among the A_3B compounds with close-packed structure. Thus, in order to use the δ phase as a strengthener, it is important to find the way to change its precipitation morphology more fine and uniform. The misfit accommodation between the δ and γ phases by alloying is one of the effective ways to change its morphology. In this study, phase equilibria among the phases including γ-nickel solid solution and Ni_3Nb-δ in Ni-rich corner of Ni-Nb-M (M : Fe, Co, Al, Ti, V) ternary systems at elevated temperatures have been examined. We have found that the solid solubility of δ phase field in these systems, and the crystal structure becomes more symmetrical by the addition these element but Al.Based on the knowledge of phase diagrams and crystal symmetry, , the effect of Fe, for example, on precipitation of the δ phase in the γ Ni solid solution was studied. The addition of Fe drastically refines the morphology of the δ precipitates. TEM weak beam analysis revealed the a-axis misfit dislocation density increases with Fe content. This is because of the increase in the lattice misfit along the a-axis. The introduction of the misfit dislocations makes the growth kinetics sluggish, which is responsible for the refinement of the δ precipitates in Fe containing alloys. The effects of other elements on the precipitation kinetics and morphology of the δ phase have been demonstrated, and the alloy design using the δ phase by controlling the morphology has been demonstrated.

金属间化合物Ni_3Nb（δ）由于其在熔化温度以下的相稳定性而被用作镍基合金的强化剂。δ相的晶体结构为有序正交（DO_a结构），是A_3B化合物中晶体对称性最低的密排结构。因此，为了使用δ相作为强化剂，重要的是找到使其沉淀形态更细和更均匀的方法。合金化使δ相和γ相错配协调是改变其形貌的有效途径之一。本文研究了Ni-Nb-M（M：Fe，Co，Al，Ti，V）三元系中γ-Ni固溶体和富Ni角Ni_3Nb-δ相之间的高温相平衡。发现除Al外，δ相在这些体系中的固溶度都有所提高，晶体结构也变得更加对称。根据相图和晶体对称性的知识，以Fe为例，研究了Fe对γ Ni固溶体中δ相析出的影响。Fe的加入显著细化了δ相的形貌。TEM弱束分析表明，a轴失配位错密度随Fe含量的增加而增加。这是因为晶格失配沿着a轴增加。失配位错的引入使δ相的生长动力学变得缓慢，这是含Fe合金中δ相细化的原因。研究了其它元素对δ相析出动力学和形态的影响，并通过控制δ相的形态进行了合金设计。

项目成果

T.Ueyama et al.: "Phase Stability of Ni_3Nb-δ Phase in Ni-Nb-M Systems at Elevated Temperatures"Thermec '97, The TMS. 1753-1760 (1997)

T. Ueyama 等人：“高温下 Ni-Nb-M 系统中 Ni_3Nb-δ 相的相稳定性”Thermec 97，TMS 1753-1760 (1997)。

T.Ueyama, M.Ghanem, N.Miura, M.TakeyamaT.Matsuo: "Phase Stability of Ni_3Nb-δ Phase inNi-Nb-M Systems at Elevated Temperatures"Proc.Int.Conf.on Thermec '97-. TMS. 1753-1760 (1997)

T.Ueyama、M.Ghanem、N.Miura、M.TakeyamaT.Matsuo：“高温下 Ni-Nb-M 系统中 Ni_3Nb-δ 相的相稳定性”Proc.Int.Conf.on Thermec 97-。 1753-1760 (1997)

M.Takeyama, H.Yokota, M.M.Ghanem, and T.Matsuo: "Phase Equilibria and Microstructure Control Using Ni_3Nb-δ Phase in Ni-Nb-Fe Ternary System at Elevated Temperatures"THERMEC '2000, Procesing & Manufactureing of Advanced Materials. (in press). (2000)

M.Takeyama、H.Yokota、M.M.Ghanem 和 T.Matsuo：“高温下 Ni-Nb-Fe 三元体系中 Ni_3Nb-δ 相的相平衡和微观结构控制”THERMEC 2000，先进材料的加工和制造。 （正在出版）。

T.UEYAMA et al.: "Phase stability of Ni_3Nb-δ phase in Ni-Nb-M systems at elevated temperatures" Thermec '97,Int.Conf.on Thermo.Processing of Steels & Other Materials. 1753-1760 (1997)

T.UEYAMA 等人：“Ni-Nb-M 系统中 Ni_3Nb-δ 相在高温下的相稳定性”Thermec 97，Int.Conf.on Thermo.Processing of Steels & Other Materials 1753-1760 (1997)。

M.M.Ghanem et al.: "Determination of phase equilibria among γ,δ and γ′ phases in Ni-Al-Nb system at ternary eutectic temperatures" 日本金属学会講演概要集. 121. 388 (1997)

M.M.Ghanem 等人：“三元共晶温度下 Ni-Al-Nb 体系中 γ、δ 和 γ′ 相平衡的测定”日本金属学会讲座摘要。121. 388 (1997)