scholarly journals Hydrogen permeable membranes based on niobium foils coated with layer of tungsten and molybdenum in niobium solid solution characteristics research

2018 ◽  
Author(s):  
A. V Panichkin ◽  
B. K. Kenzhaliyev ◽  
A. M. Derbisalin ◽  
A. A. Mamayeva ◽  
D. M. Dzhumabekov
Keyword(s):  
Solid Solution ◽  
Niobium Solid Solution

High Temperature Properties of Refractory Intermetallics

1990 ◽  
Vol 213 ◽  
Author(s):  
D.L. Anton ◽  
E. Hartford CT ◽  
D.M. Shah ◽  
Pratt Whitney ◽  
E. Hartford CT
Keyword(s):  
Solid Solution ◽  
Tensile Strength ◽  
High Temperature ◽  
Low Temperature ◽  
Ultimate Tensile Strength ◽  
Melting Temperatures ◽  
Structural Applications ◽  
Oxidation Resistant ◽  
Low Temperature Toughness ◽  
Niobium Solid Solution

AbstractOn the basis of creep strength, ultimate tensile strength and oxidation resistance, seven intermetallic compounds with melting temperatures above 1600°C have been selected as possible candidate materials for high temperature structural applications in advanced aero-turbines. These compounds, Nb3Al, Cr3Si, Co2Nb, Cr2Nb, MoSi2, Mo5Si3 and Nb2Al, have been evaluated and their properties reported herein. All seven of the compounds displayed excellent creep resistance at 1200°C with Mo5Si3 and Nb2Al being the strongest. Nb3Al, with the precipitation of the niobium solid solution displayed the greatest low temperature toughness. The greatest ultimate tensile strengths were observed for Co2Nb and MoSi2, while MoSi2 was by far the most oxidation resistant.

Short-range order in uranium-niobium solid solution

1970 ◽  
Vol 34 (2) ◽  
pp. 160-164 ◽  
Author(s):  
S.V. Strelova ◽  
Ya S. Umansky ◽  
O.S. Ivanov
Keyword(s):  
Solid Solution ◽  
Short Range ◽  
Short Range Order ◽  
Range Order ◽  
Niobium Solid Solution

scholarly journals Tin Addition to Improve the Oxidation Behaviour of NbSs/Nb5Si3 Based In Situ Composite

2011 ◽  
Vol 278 ◽  
pp. 575-580 ◽  
Author(s):  
Stephane Knittel ◽  
Stéphane Mathieu ◽  
Michel Vilasi
Keyword(s):  
Crystal Structure ◽  
Solid Solution ◽  
Oxidation Resistance ◽  
Oxidation Behaviour ◽  
Oxide Scales ◽  
Niobium Solid Solution

This work focuses on the effect of tin additions (2, 5 and 8%) to the MASC alloy (Nb-25Ti-8Hf-2Cr-2Al-18Si) on the microstructure and the oxidation behaviour at 815°C in air. The alloys are mainly constituted of a niobium solid solution plus the () Nb5Si3 silicides. For the higher Sn additions (5 and 8%), a fourth phase is evidenced: it is enriched in Sn and has a crystal structure close to Nb3Sn. The oxidation resistance of these alloys is clearly improved by tin additions: the oxygen inward diffusion is hindered and consequently the fragmentation of the silicides is avoided. Cracks in silicides are no longer observed for the MASC containing 8%Sn. This effect is not attributed to a better efficiency of the oxide scales but rather to the reduction of the niobium solid solution fraction with tin additions.

Effect of Isothermal Forging on Microstructures and Mechanical Properties of Nb-Si In Situ Composite

2007 ◽  
Vol 561-565 ◽  
pp. 423-426 ◽  
Author(s):  
Yong Wang Kang ◽  
Shi Yu Qu ◽  
Ya Fang Han ◽  
Ji Xia Song ◽  
Ding Zhong Tang
Keyword(s):  
Solid Solution ◽  
High Temperature ◽  
Nominal Composition ◽  
Temperature Structure ◽  
X Ray Diffraction ◽  
In Situ Composite ◽  
Large Size ◽  
Directional Texture ◽  
Niobium Solid Solution

Nb-Si based in-situ composites have great potential for the application of high temperature structure components. In this paper, the influence of microstructure on the compression behavior of Nb-Si in-situ composite forged at high temperature was studied. The alloy with nominal composition of Nb-12Si-24Ti-4Cr-4Al-2Hf was consumable arc-melted, and then isothermal forged at 960°C. Scanning electron microscopy (SEM), energy-dispersive spectroscopy (EDS) and X-ray diffraction (XRD) were used to characterize the microstructure, composition and phases. The compressive behaviors at 1250°C were carried out by Gleeble thermo-mechanical simulator. The results showed that the microstructures were inhomogenous in the different sections of the ingot, and no evident directional texture formed, and the main phases were niobium solid solution, Nb5Si3 and Ti5Si3. However, no macro-elements segregation in the ingot was observed. The compression strength was in the range of 140-360MPa. BSE observation showed that irregular-shaped Nb5Si3 and Ti5Si3 phases distributed in Nb solid solution and the size of Nb5Si3 in three tested samples was 10μm. Large size of eutectoid texture existed in the sample with strength of ~140MPa. On the contrary, in the sample with higher strength of 360MPa, eutectoid structures were hardly detected. The results suggested that the strength decreased gradually with size increase of eutectoid structure.

NiAl precipitation in Fe-12w/o Cr-5w/o Ni-4w/o Al

1983 ◽  
Vol 41 ◽  
pp. 202-203
Author(s):  
L.E. Murr ◽  
J.S. Dunning ◽  
S. Shankar
Keyword(s):  
Solid Solution ◽  
Stainless Steel ◽  
Stainless Steels ◽  
Alloy Composition ◽  
Chromium Content ◽  
Scale Up ◽  
Optical Metallography ◽  
Property Evaluation ◽  
310 Stainless Steel ◽  
Microstructural Studies

Aluminum additions to conventional 18Cr-8Ni austenitic stainless steel compositions impart excellent resistance to high sulfur environments. However, problems are typically encountered with aluminum additions above about 1% due to embrittlement caused by aluminum in solid solution and the precipitation of NiAl. Consequently, little use has been made of aluminum alloy additions to stainless steels for use in sulfur or H2S environments in the chemical industry, energy conversion or generation, and mineral processing, for example.A research program at the Albany Research Center has concentrated on the development of a wrought alloy composition with as low a chromium content as possible, with the idea of developing a low-chromium substitute for 310 stainless steel (25Cr-20Ni) which is often used in high-sulfur environments. On the basis of workability and microstructural studies involving optical metallography on 100g button ingots soaked at 700°C and air-cooled, a low-alloy composition Fe-12Cr-5Ni-4Al (in wt %) was selected for scale up and property evaluation.

Solid Solution Effects and Deformation Micros trueture of Shock-Loaded Iron Manganese Alloys

1970 ◽  
Vol 28 ◽  
pp. 420-421
Author(s):  
A. Christou ◽  
J. V. Foltz ◽  
N. Brown
Keyword(s):  
Solid Solution ◽  
Shock Loading ◽  
High Strain ◽  
Local Stress ◽  
Strain Rates ◽  
Local Stress Concentration ◽  
Bcc Metals ◽  
Manganese Alloys ◽  
Iron Manganese ◽  
Transmission Microscope

In general, all BCC transition metals have been observed to twin under appropriate conditions. At the present time various experimental reports of solid solution effects on BCC metals have been made. Indications are that solid solution effects are important in the formation of twins. The formation of twins in metals and alloys may be explained in terms of dislocation mechanisms. It has been suggested that twins are nucleated by the achievement of local stress-concentration of the order of 15 to 45 times the applied stress. Prietner and Leslie have found that twins in BCC metals are nucleated at intersections of (110) and (112) or (112) and (112) type of planes.In this paper, observations are reported of a transmission microscope study of the iron manganese series under conditions in which twins both were and were not formed. High strain rates produced by shock loading provided the appropriate deformation conditions. The workhardening mechanisms of one alloy (Fe - 7.37 wt% Mn) were studied in detail.

Fine Microstructure of a Mechanically Alloyed Oxide Dispersion Strengthened Nickel-Base Superalloy

1977 ◽  
Vol 35 ◽  
pp. 298-299
Author(s):  
Jordi Marti ◽  
Timothy E. Howson ◽  
David Kratz ◽  
John K. Tien
Keyword(s):  
Solid Solution ◽  
Volume Fraction ◽  
Stress Rupture ◽  
Oxide Dispersion Strengthened ◽  
Solid Solution Alloy ◽  
Oxide Dispersion ◽  
Creep And Stress Rupture ◽  
Mechanically Alloyed ◽  
Fine Microstructure ◽  
Nickel Base

The previous paper briefly described the fine microstructure of a mechanically alloyed oxide dispersion strengthened nickel-base solid solution. This note examines the fine microstructure of another mechanically alloyed system. This alloy differs from the one described previously in that it is more generously endowed with coherent precipitate γ forming elements A1 and Ti and it contains a higher volume fraction of the finely dispersed Y2O3 oxide. An interesting question to answer in the comparative study of the creep and stress rupture of these two ODS systems is the role of the precipitate γ' in the mechanisms of creep and stress rupture in alloys already containing oxide dispersoids.The nominal chemical composition of this alloy is Ni - 20%Cr - 2.5%Ti - 1.5% A1 - 1.3%Y203 by weight. The system receives a three stage heat treatment-- the first designed to produce a coarse grain structure similar to the solid solution alloy but with a smaller grain aspect ratio of about ten.

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