Transition alpha structure in beta-isomorphous Nb-Hf alloys

1987 ◽  
Vol 45 ◽  
pp. 232-233
Author(s):  
R.W. Carpenter ◽  
Changhai Li ◽  
David J. Smith
Keyword(s):  
Solid Solution ◽  
Solution Phase ◽  
Miscibility Gap ◽  
Large Strains ◽  
Solid Solution Phase ◽  
Two Phase ◽  
Diffuse Intensity ◽  
Metastable Form ◽  
The Matrix ◽  
Equilibrium Morphology

Binary Nb-Hf alloys exhibit a wide bcc solid solution phase field at temperatures above the Hfα→ß transition (2023K) and a two phase bcc+hcp field at lower temperatures. The β solvus exhibits a small slope above about 1500K, suggesting the possible existence of a miscibility gap. An earlier investigation showed that two morphological forms of precipitate occur during the bcc→hcp transformation. The equilibrium morphology is rod-type with axes along <113> bcc. The crystallographic habit of the rod precipitate follows the Burgers relations: {110}||{0001}, <112> || <1010>. The earlier metastable form, transition α, occurs as thin discs with {100} habit. The {100} discs induce large strains in the matrix. Selected area diffraction examination of regions ∼2 microns in diameter containing many disc precipitates showed that, a diffuse intensity distribution whose symmetry resembled the distribution of equilibrium α Bragg spots was associated with the disc precipitate.

Phase relationships in the Ce–Nd–B system at 773 K

2020 ◽  
Vol 111 (6) ◽  
pp. 526-532
Author(s):  
Xuehong Cui ◽  
Jinming Zhu ◽  
Ketong Luo ◽  
Jianlie Liang
Keyword(s):  
Solid Solution ◽  
Ternary System ◽  
Continuous Solid Solution ◽  
Solution Phase ◽  
Solid Solution Phase ◽  
X Ray Diffraction ◽  
Two Phase ◽  
X Ray ◽  
Three Phase ◽  
Phase Relationships

Abstract Phase relationships in the Ce-Nd-B ternary system at 773 K were investigated by means of X-ray diffraction and scanning electron microscopy with energy dispersive X-ray spectroscopy techniques. Six borides, i. e. CeB4, CeB6, NdB4, NdB6, NdB66 and Nd2B5 are confirmed in this work. No ternary compound was observed. CeB4 and NdB4 were discovered to form the continuous solid solution phase (Ce,Nd)B4, CeB6 and NdB6 also form the solid solution phase (Ce,Nd)B6. The maximum solid solubility of Ce in (Ce,Nd)2B5 phase is 46.5 at.%. The isothermal section of the Ce-Nd-B ternary system at 773 K consists of 3 three-phase regions, 7 two-phase regions and 7 single- phase regions.

scholarly journals The Fine Line between a Two-Phase and Solid-Solution Phase Transformation and Highly Mobile Phase Interfaces in Spinel Li4+ x Ti5 O12

2016 ◽  
Vol 7 (9) ◽  
pp. 1601781 ◽  
Author(s):  
Swapna Ganapathy ◽  
Alexandros Vasileiadis ◽  
Jouke R. Heringa ◽  
Marnix Wagemaker
Keyword(s):  
Solid Solution ◽  
Phase Transformation ◽  
Mobile Phase ◽  
Solution Phase ◽  
Solid Solution Phase ◽  
Two Phase ◽  
Fine Line

Non-equilibrium Ti-Fe bulk alloys with ultra-high strength and enhanced ductility

2004 ◽  
Vol 851 ◽  
Author(s):  
Dmitri V. Louzguine-Luzgin ◽  
Larissa V. Louzguina-Luzgina ◽  
Hidemi Kato ◽  
Akihisa Inoue
Keyword(s):  
Solid Solution ◽  
Supersaturated Solid Solution ◽  
High Strength ◽  
Eutectic Structure ◽  
Solution Phase ◽  
Solid Solution Phase ◽  
Mechanical Fracture ◽  
Glassy Alloys ◽  
Fe Alloys ◽  
Bulk Alloys

ABSTRACTThe high-strength and ductile hypo-, hyper- and eutectic Ti-Fe alloys were formed in the shape of the arc-melted ingots with the dimensions of about 25–40 mm in diameter and 10–15 mm in height. The structure of the samples consists of cubic Pm 3 m TiFe and BCC Im 3 m β-Ti supersaturated solid solution phase. The arc-melted hypereutectic Ti65Fe35 alloy has a dispersed structure consisting of the primary TiFe phase and submicron-size eutectic structure. This alloy exhibits excellent mechanical properties: a Young's modulus of 149 GPa, a high mechanical fracture strength of 2.2 GPa, a 0.2 % yield strength of 1.8 GPa and 6.7 % ductility. The hard round-shaped intermetallic TiFe phase and the supersaturated β-Ti solid solution result in a high strength of the Ti65Fe35 alloy which in addition has much higher ductility compared to that of the nanostructured or glassy alloys. The reasons for the high ductility of the hypereutectic alloy are discussed.

Nanocrystalline Ni-30wt%Fe Supersaturated Solid Solution Synthesized by Mechanical Alloying

2014 ◽  
Vol 490-491 ◽  
pp. 38-42
Author(s):  
Yu Chen ◽  
Yang Yu ◽  
Wen Cong Zhan ◽  
Er De Wang
Keyword(s):  
Solid Solution ◽  
Crystallite Size ◽  
Powder Mixture ◽  
Supersaturated Solid Solution ◽  
Average Crystallite Size ◽  
Solution Phase ◽  
Elemental Powder ◽  
Solid Solution Alloy ◽  
Solid Solution Phase ◽  
Elemental Powder Mixture

Ni-30wt%Fe elemental power mixture was mechanically milled under argon atmosphere for variuos times up to 25h.The evolution of Ni-Fe alloying during milling and the microstructure of the as-milled powders were characterized by XRD, EPMA (electron probe microanalysis), SEM and TEM, respectively. The results show that nanocrystalline Ni (Fe) supersaturated solid solution alloy powders with 30wt. % Fe in composition can be synthesized by mechanical milling of the elemental powder mixture. Both the content of Fe dissolved and the microstrain developed in the as-synthesized Ni (Fe) solid solution phase increase, while the crystallite size decreases, steadily with increasing milling time. In particular, the Ni-30wt%Fe alloy powders obtained by 25h milling consist of a single Ni (Fe) supersaturated solid solution phase with average crystallite size of about 15nm and accumulated microstrain as high as 1.12%. DSC tests show that the nanocrystalline Ni-30wt%Fe alloy powders have a lower melting temperature than the elemental powder mixture, attributed to the unique Ni (Fe) solid solution phase structure, the nanocrystallization, and the high strain energy.

Interaction between Two Ni-Base Alloys and Ceramic Moulds

2013 ◽  
Vol 747-748 ◽  
pp. 765-771 ◽  
Author(s):  
Jian Sheng Yao ◽  
Ding Zhong Tang ◽  
Xiao Guang Liu ◽  
Cheng Bo Xiao ◽  
Xin Li ◽  
...  
Keyword(s):  
Solid Solution ◽  
Interface Reaction ◽  
Vapour Phase ◽  
Optical Microscope ◽  
Solution Phase ◽  
Solid Solution Phase ◽  
X Ray Diffraction ◽  
X Ray ◽  
Scanning Electron ◽  
Reaction Surfaces

The interfacial reactions between ceramic moulds and DZ417G and DZ125 superalloys were investigated. The microstructure and composition of the interface region were observed by optical microscope, X-ray diffraction and scanning electron microscope with energy dispersive spectroscopy. The results showed that (Al1-xCrx)2O3solid solution phase with pink color was formed from the dissolution of Cr2O3and Al2O3and vapour phase, which was transferred to the reaction surfaces. The reaction layer thicknesses of DZ417G and DZ125 alloys were about in the range of 40-50μm. The interface reaction product between DZ417G alloy and ceramic mould was TiO2and the product between DZ125 alloy and ceramic mould was HfO2.

Discovery of a thermally persistent h.c.p. solid-solution phase in the Ni-W system

2014 ◽  
Vol 116 (8) ◽  
pp. 083515 ◽  
Author(s):  
S. J. B. Kurz ◽  
S. B. Maisel ◽  
A. Leineweber ◽  
M. Höfler ◽  
S. Müller ◽  
...  
Keyword(s):  
Solid Solution ◽  
Solution Phase ◽  
Solid Solution Phase

scholarly journals Elasticity of Phases in Fe-Al-Ti Superalloys: Impact of Atomic Order and Anti-Phase Boundaries

Crystals ◽  
2019 ◽  
Vol 9 (6) ◽  
pp. 299 ◽  
Author(s):  
Martin Friák ◽  
Vilma Buršíková ◽  
Naděžda Pizúrová ◽  
Jana Pavlů ◽  
Yvonna Jirásková ◽  
...  
Keyword(s):  
Solid Solution ◽  
Chemical Composition ◽  
Elastic Properties ◽  
Formation Energy ◽  
Chemical Species ◽  
Two Phase ◽  
Nano Structure ◽  
The Matrix ◽  
Free Material ◽  
Excess Fe

We combine theoretical and experimental tools to study elastic properties of Fe-Al-Ti superalloys. Focusing on samples with chemical composition Fe71Al22Ti7, we use transmission electron microscopy (TEM) to detect their two-phase superalloy nano-structure (consisting of cuboids embedded into a matrix). The chemical composition of both phases, Fe66.2Al23.3Ti10.5 for cuboids and Fe81Al19 (with about 1% or less of Ti) for the matrix, was determined from an Energy-Dispersive X-ray Spectroscopy (EDS) analysis. The phase of cuboids is found to be a rather strongly off-stoichiometric (Fe-rich and Ti-poor) variant of Heusler Fe2TiAl intermetallic compound with the L21 structure. The phase of the matrix is a solid solution of Al atoms in a ferromagnetic body-centered cubic (bcc) Fe. Quantum-mechanical calculations were employed to obtain an insight into elastic properties of the two phases. Three distributions of chemical species were simulated for the phase of cuboids (A2, B2 and L21) in order to determine a sublattice preference of the excess Fe atoms. The lowest formation energy was obtained when the excess Fe atoms form a solid solution with the Ti atoms at the Ti-sublattice within the Heusler L21 phase (L21 variant). Similarly, three configurations of Al atoms in the phase of the matrix with different level of order (A2, B2 and D03) were simulated. The computed formation energy is the lowest when all the 1st and 2nd nearest-neighbor Al-Al pairs are eliminated (the D03 variant). Next, the elastic tensors of all phases were calculated. The maximum Young’s modulus is found to increase with increasing chemical order. Further we simulated an anti-phase boundary (APB) in the L21 phase of cuboids and observed an elastic softening (as another effect of the APB, we also predict a significant increase of the total magnetic moment by 140% when compared with the APB-free material). Finally, to validate these predicted trends, a nano-scale dynamical mechanical analysis (nanoDMA) was used to probe elasticity of phases. Consistent with the prediction, the cuboids were found stiffer.

scholarly journals Effect of CNT Contents on the Microstructure and Properties of CNT/TiMg Composites

Materials ◽  
2019 ◽  
Vol 12 (10) ◽  
pp. 1620
Author(s):  
Xiaomin Yuan ◽  
Haonan Zhu ◽  
Huiling Ji ◽  
Yiwei Zhang
Keyword(s):  
Cross Section ◽  
Optical Microscope ◽  
Solution Phase ◽  
Solid Solution Phase ◽  
Wet Milling ◽  
X Ray Diffraction ◽  
X Ray ◽  
Microstructure Observation ◽  
The Matrix ◽  
Scanning Electron

Carbon nanotubes (CNTs), dispersed in absolute ethanol, were evenly mixed into Ti/MgH2 powders by wet milling. Then, we applied the vacuum hot-pressed sinteringmethod to the CNTs/TiMg composite materials. An optical microscope (OM), X-ray diffraction (XRD), scanning electron microscopy (SEM) with energy dispersive spectroscopy (EDS) and a field emission scanning electron microscope (FESEM) were used for the microstructure observation and phase analysis of samples. The mechanical properties were measured via the micro-vickers hardness. The results show that the main phases in the composites were Ti, Mg and C. Meanwhile, a small amount of Ti-Mg solid solution phase was also found. The cross-section morphology of the composites shows that the melted magnesium fills the grain interface during extrusion and that the composites have a better compactness.The microstructures of the composites have been greatly refined as the CNT contents increased. The structure of the composites was further refined when 0.5 wt.% CNTs were added. The fracture surface is obviously a ductile fracture. The microhardness increases obviously with the CNT content increasing. When the content of the CNTs is 1.0 wt.%, the microhardness of the composites reaches 232 HV, which is 24% higher than that of the matrix.

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