Ni-Fe-Mo三元系1373K等温截面的研究

采用三元扩散偶技术测定了Ni—Fe—Mo三元系1373Ni—Fe—Mo三元扩散偶的相区成分，并对其相关系进行了研究。K的等温截面，借助电子探针微区成分分析方法分析了测得Ni-Fe-Mo三元扩散偶在1373K下存在2个二元中间化合物：μ和NiMo。该三元系在1373K存在3个三相区：μ＋bcc（Mo）＋NiMo；μ＋NiMo＋fcc；bcc（Fe）＋μ＋fcc：在此温度的扩散偶中未发现三元中间化合物。     

β钛合金的研究进展

采用扩散偶技术测定了Fe-Ni-Nb三元系1198 K的等温截面,借助电子探针微区成分分析方法对Fe-Ni-Nb三元扩散偶的相区成分,及相关系进行研究.结果表明:Fe-Ni-Nb三元扩散偶在1198 K时生成μ,Fe2Nb,Ni6Nb7和Ni3Nb 4个中间化合物.μ相与Ni6Nb7形成连续固溶体,表示为(Fe,Ni)6Nb7.该等温截面形成γ(Fe,Ni) Fe2Nb Ni3Nb,Fe2Nb Ni3Nb (Fe,Ni)6Nb72个三相区,没有发现三元化合物.     

Nb—Ti—Si三元系1473K等温截面的测定

运用扩散偶技术结合电子探针微区成分分析方法对Nb-Ti-Si三元扩散偶进行相分析，测得Nb-Ti-Si三元系1473K下所生成的7个扩散层，分别是TiSi2,TiSi,Ti5Si3,Nb5Si2和M3Si，此扩散偶中未发现三元化合物，并根据扩散偶中的相区分布和相图中相区分布的关系，得出Nb-Ti-Si三元系1473K下的等温截面。     

Ni-Cr-Mo三元系1358 K等温截面的测定

应用三元扩散偶技术测定了Ni-Cr-Mo三元系1358 K的等温截面,借助电子探针微区成分分析方法分析了Ni-Cr-Mo三元扩散偶的相区成分,并对其相关系进行了研究.测得Ni-Cr-Mo三元扩散偶在1358 K下存在一个中间化合物NiMo,Cr和Mo在扩散偶中形成连续固溶体,Ni和（Cr,Mo）有限固溶,扩散偶中未发现三元中间化合物.实验发现Ni-Cr-Mo三元系1358 K的等温截面存在一个三相区：Ni＋NiMo＋（Cr,Mo）.     

Ni-Mo-Re三元系1473K等温截面的研究

采用三元扩散偶技术测定了Ni-Mo-Re三元系1473 K的等温截面,借助电子探针微区成分分析方法分析了Ni-Mo-Re三元扩散偶的相区成分,并对其相关系进行了研究.Ni-Mo-Re三元扩散偶在1473 K时存在3个二元中间化合物:X,σ和NiMo,在此温度的扩散偶中未发现三元中间化合物.经分析,Ni-Mo-Re三元系在1473K存在4个三相区:Re Ni X;Ni NiMo σ;σ X Ni;σ Mo NiMo.     

Nb-Ti-Co氢分离合金优化设计和渗氢性能:I.合金相图和渗氢成分区域构建

基于CALPHAD方法和Thermo-Calc软件构建了Nb-Ti-Co三元合金富Nb角相图,而后结合微观偏析统一模型研究58种合金的凝固路径,探讨固相反扩散系数和冷却速率对凝固路径的影响规律,并利用Bridgman定向凝固实验对其验证,最后通过SEM和XRD观察上述合金的微观结构,并与数值模拟计算结果进行比较,建立了Nb-Ti-Co相图中的渗氢成分区域。结果表明:1)Nb-Ti-Co三元合金相图富Nb角存在两个三元四相平衡反应,分别为L+α-Nb→TiCo+Co_6Nb_7(1225.35℃)和L+TiCo→α-Nb+Ti_2Co(1099.06℃);2)Nb相区中至少存在四种不同的凝固路径,分别为(L+α-Nb)、(L+α-Nb)→(L+α-Nb+Co_6Nb_7)→(L+α-Nb+Co_6Nb_7+TiCo)、(L+α-Nb)→(L+α-Nb+TiCo)和(L+α-Nb)→(L+α-Nb+TiCo)→(L+α-Nb+TiCo+Ti_2Co);3)冷却速率(R_f)对渗氢区域内合金凝固路径影响较小,相反,固相反扩散系数(Ф)对其凝固路径影响较大;4)渗氢区域内合金显微组织中初生α-Nb相体积分数随着Nb含量和Ti/Co比率的增加而增加,相反,两相共晶体积分数随之而降低。     

Nb-Ti-Co氢分离合金近共晶点处的显微组织及其渗氢性能

探寻了Nb-Ti-Co氢分离合金的共晶点成分并利用Bridgman定向凝固实验对其进行验证,研究了近共晶点处9种合金的显微组织、氢渗透性能及氢脆现象,并与贵金属Pd的氢渗透性能进行比较.结果表明,Nb-Ti-Co三元合金中完全由共晶Nb[Ti,Co)+TiCo相构成的合金成分为Nb_(31)Ti_(35)Co_(34);当Bridgman定向凝固实验的抽拉速率为5μm/s时,共晶组织中的2相呈现岀规则的共生生长.9种合金中完全由共晶相构成的合金在673.5 K具有最大的氢渗透系数2.7×10~(-8)mol/(m·s·Pa~(0.5)),是相同条件下Pd的氢渗透系数的1.72倍;Nb含量相同时,随着Ti/Co比值的降低,氢渗透系数逐渐减小.氢渗透过程中,合金膜内部的初生TiCo相作为裂纹源首先萌生裂纹,而后以此发生二次裂纹现象并逐渐向膜边缘扩展;当TiCo相体积分数小于5%时,共晶Nb(Ti,Co)+TiCo相抵消原有初生TiCo相上的裂纹源,使得合金膜具有良好的抗氢脆性能.     

Al-Ti-Zr三元系1073K等温截面的测定（英文）

采用合金样与扩散偶相结合的方法,利用电子探针射线显微分析(EPMA)对Al-Ti-Zr三元系的1073 K等温截面的相关系进行实验测定。结果表明:截面中存在一个Al含量(摩尔分数)达到16.3%的β(Ti,Zr)固溶体。Ti和Zr可以在大多数Al-Zr和Ti-Al二元中间化合物中相互取代。其中,Zr在Ti_3Al和Ti Al中的最大固溶度分别达到17.9%和4.0%。该等温截面共包含16个单相区,27个两相区和14个三相平衡,没有检测到三元化合物。     

Ni—Re—Ta三元系1473K等温截面的测定

应用三元扩散偶技术测定Ｎｉ－Ｒｅ－Ｔａ三元系１４７３Ｋ的等温截面。用电子探针微区成分分析方法对Ｎｉ－Ｒｅ－Ｔａ三元扩散偶进行是得Ｎｉ－Ｒｅ－Ｔａ三元系在１４７３Ｋ下生成ｉ３Ｔａ、Ｎｉ２Ｔａ、ＮｉＴａ、ＮＩＴａ２和ｘ相５个扩散层,在扩散 未发现三元化合物。     

Ti-Ni-Pt三元系相平衡关系（英文）

采用扩散偶辅以平衡合金法的方法,利用电子探针(EPMA)和X射线衍射(XRD)等分析手段对Ti-Ni-Pt三元系的1073和1173 K等温截面的相关系进行实验测定。结果表明,三元化合物Ti_2(Ni,Pt)_3和二元化合物Ti_3Pt_5、TiPt_(3-)在1073和1173 K是稳定的。部分二元化合物具有较大的第三组元固溶度,如在1073和1173 K下,Pt在TiNi中的固溶度分别约为36%和40%(摩尔分数)。此外,在1073~1173 K的温度区间内存在零变量反应TiNi_(3+)Ti_3Pt_5→Ti_2(Ni,Pt)_(3+)TiPt_(3+)。     

Transformations and phase relations in Nb—Ti—Si ternary system at 1373—1473K

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Determination of isothermal sections of Ni-Cr-Nb ternary system

The isothermal sections of Ni-Cr-Nb ternary system at 1 323 K and 1 423 K were determined by means of diffusion triple and energy spectrum analysis (ESA). By analyzing the diffusion layers in the diffusion couples, the compounds forming in this system were identified. There are three similar compounds found at these two temperatures: Ni3 Nb, NiNb and NbCr2-R, and four similar three-phase regions are found : (Ni) (Cr) Ni3 Nb, Ni3Nb NbCr2-R NiNb, NbCr2-R (Cr) Ni3 Nb, NbCr2-R NiNb (Nb). The results show that no phase transformation happens between these tow temperatures. But the solid solubilities of the binary compounds at 1423 K become bigger than those at 1 323 K, especially the solid solubility of NbCr2-R. No ternary compound is observed.     

Tracer diffusion of niobium and titanium in binary and ternary titanium aluminides

This study presents recent results on titanium (Ti) and niobium (Nb) diffusion in binary (α₂-Ti₃Al and γTiAl) and ternary high-Nb-containing (γTiAl-10Nb) Ti aluminides. Three different techniques were used to measure self-diffusion and solute (Nb) diffusion. The radiotracer technique combined with mechanical sectioning by grinding was applied at higher temperatures, whereas ion-beam sputtering or secondary ion mass spectrometry was used to analyze the short penetration profiles at lower temperatures. The results measured by these different techniques for different penetration depths are very consistent. Nb is a slower diffuser compared to Ti in the ternary as well as in the binary Ti aluminides. The heavy alloying of γTiAl with 10at.% Nb, however, enhances significantly both the Ti and the Nb diffusivities. The diffusion mechanisms for Ti and Nb in ordered Ti aluminides are discussed.     

Determination of isothermal sections of the Co-Nb-Ni and Ni-Mo-Re ternary systems

The isothermal sections of the Co-Nb-Ni ternary system at 1373 K and the Ni-Mo-Re ternary system at 1473 K were determined by means of diffusion triple and electron probe microanalysis (EPMA).The results indicate that there are three three-phase regions found in the Co-Nb-Ni ternary system at 1373 K:(Ni,Co) NbCo3 Ni3Nb,NbCo3 NbCo2 Ni3Nb,and NbCo2 μ Ni3Nb;and four three-phase regions found in the Ni-Mo-Re ternary system at 1473 K:Re Ni χ,Ni NiMo σ,σ χ Ni,and σ Mo NiMo.No ternary eompoond is observed in the two isothermal sections.The isothermal sections arc contrasted with the previous study.     

Effects of ternary additions on the microstructure and thermal stability of directionally-solidified MoSi2/Mo5Si3 eutectic composites

Effects of ternary additions on the microstructure and thermal stability of directionally-solidified MoSi₂/Mo₅Si₃ eutectic composites have been studied for twelve different elements (Ti, V, Cr, Fe, Co, Ni, Nb, Ta, W, Ir, B and C) paying special attention to the variation of lattice misfits and interface segregation behavior with ternary additions. Among six elements (type-1: Ti, V, Cr, Nb, Ta and W) with a relatively high solubility in MoSi₂ and Mo₅Si₃, Ta and W are found to be beneficial to microstructure refinement. All other six ternary elements (type-2: Fe, Co, Ni, Ir, B and C) with a negligibly low solubility in MoSi₂ and Mo₅Si₃ exhibit a strong tendency to segregate on MoSi₂/Mo₅Si₃ interfaces, resulting in both microstructure refinement and the modification of the interface morphology.     

The isothermal section of the Ti–Co–Zr ternary system at 773 K

The phase equilibria of the Ti–Co–Zr ternary system at 773 K have been investigated mainly by powder X-ray diffraction (XRD), scanning electron microscope (SEM) and energy dispersive analysis (EDX). The isothermal section consists of 16 single-phase regions, 31 two-phase regions and 16 three-phase regions. There are 11 binary compounds, i.e. CoZr₃, CoZr₂, CoZr, Co₂Zr, Co₂₃Zr₆, Co₁₁Zr₂, TiCo₃, h-TiCo₂, c-TiCo₂, TiCo, Ti₂Co in the system. The existence of two ternary compounds Co₁₀Ti₇Zr₃ and Co₆₆Ti₁₇Zr₁₇ has been confirmed at 773 K. Co₂Zr, CoZr₃ and TiCo have a range of homogeneity. The solubilities of Ti in CoZr was determined to be up to 8.1 at.% Ti.     

合金元素对新型Co-Al-W合金热腐蚀行为的影响

研究了由γ'-Co₃(Al,W)相沉淀强化的新型钴基Co-Al-W 高温合金在800℃、75% Na₂SO₄+25% NaCl熔盐中的热腐蚀动力学及合金元素Mo、Nb、Ta和Ti对合金热腐蚀行为的影响。研究发现,2Mo、2Nb、 2Ta和2Ti合金比9.8W合金具有更好的抗热腐蚀能力,Mo和Ti对提高合金耐热腐蚀能力的效果比Ta和Nb显著。加入合金元素的合金热腐蚀膜由三层组成,即主要由Co氧化物CoO和Co₃O₄组成的腐蚀膜外层,由合金元素、Al、 Co及W复杂氧化物组成的中间过渡层和由Al、Co氧化物组成的腐蚀膜内层。随着腐蚀时间的增加,中间过渡层厚度逐渐增加,热腐蚀膜内、外层厚度变化不大,但内层致密性逐渐增加。     

The Nb-Ti-Si ternary phase diagram: Evaluation of liquid- solid phase equilibria in Nb-and Ti-rich alloys

Phase equilibria in ternary Nb-Ti-Si alloys have been investigated using scanning electron micros-copy, XRD, and electron beam microprobe analysis. Alloys containing up to four phases, Nb(Ti) ₅ Si ₃ , Ti(Nb) ₅ Si ₃ , (Nb,Ti) ₃ Si, and (Nb,Ti,Si) were directionally solidified using cold crucible Czochralski crystal growth. A broad range of Nb and Ti compositions were investigated for Si concentrations up to 35.0%. Microstructural and microchemical evidence provided a clear definition of the Nb-Ti-Si liquidus surface and indicate that the metal-rich end of the ternary phase diagram possesses two transition reactions: L + Nb(Ti) ₅ Si ₃ → (Nb,Ti) ₃ Si + Ti(Nb) ₅ Si ₃ L + (Nb,Ti) ₃ Si → (Nb,Ti,Si) + Ti(Nb) ₅ Si ₃ The first of these transition reactions occurs at a composition of approximately Nb-66Ti-19Si, and probably at a temperature between 1600 and 1650 ‡C. The second of these transition reactions oc-curs at a composition of approximately Nb-76Ti-13.5Si and a temperature of approximately 1350 ‡C. No ternary eutectic was observed in the compositions that were investigated.