Competitive Precipitation and Recrystallization in U-7.5Nb-2.5Zr Alloy

2014 ◽  
Vol 354 ◽  
pp. 85-91
Author(s):  
Denise A. Lopes ◽  
Thomaz Augusto Guisard Restivo ◽  
Angelo Fernando Padilha
Keyword(s):  
Grain Structure ◽  
Main Process ◽  
Gamma Phase ◽  
X Ray Diffraction ◽  
Protective Oxide ◽  
X Ray ◽  
Key Factor ◽  
Cold Rolled ◽  
Precipitation Phenomena ◽  
Precipitation Events

Abstract. Metallic nuclear fuel plates are nowadays an alternative to the ceramic ones in the sense that the uranium density can be increased at lower enrichment. Higher thermal conductivity is also a key factor favouring such fuels for power reactors. Uranium reacts promptly with oxygen and nitrogen at high temperatures to catastrophic corrosion due to non-protective oxide layers, which imparts hot forming processes. The gamma phase body centred cubic structure can be retained at room temperature by annealing the U-7.5Nb-2.5Zr (wt.%) alloy followed by quenching, where the deformation can be extensive. The resulted highly deformed gamma supersaturated structure is subjected further to competitive recovery/recrystallization and phase precipitation phenomena whose are studied in the work. The U-7.5Nb-2.5Zr alloy was melted into plasma and induction furnaces and afterwards annealed to gamma phase. The normalized alloy was cold rolled and underwent isochronal and isothermal treatments. The microstructure evolution was monitored by optical microscopy, X-ray diffraction analysis and hardness measurements. The results show the precipitation events of α” and α+γ3phases are dominant over recovery in the range 200oC < T < 500oC. Above 500oC the recrystallization is the main process leading to softening and initial Vickers hardness recovery. One refined gamma phase grain structure was obtained (~8.0 μm) after annealing at 700oC for 2.5 hours.

TEM studies of solid-state reactions in sputter-deposited Nb/Al multilayer thin films

1996 ◽  
Vol 54 ◽  
pp. 1020-1021
Author(s):  
F. Ma ◽  
S. Vivekanand ◽  
K. Barmak ◽  
C. Michaelsen
Keyword(s):  
Thin Films ◽  
Solid State ◽  
Stoichiometric Composition ◽  
Analytical Electron Microscopy ◽  
Grain Structure ◽  
Solid State Reactions ◽  
Multilayer Thin Films ◽  
X Ray Diffraction ◽  
X Ray ◽  
Sputter Deposited

Solid state reactions in sputter-deposited Nb/Al multilayer thin films have been studied by transmission and analytical electron microscopy (TEM/AEM), differential scanning calorimetry (DSC) and X-ray diffraction (XRD). The Nb/Al multilayer thin films for TEM studies were sputter-deposited on (1102)sapphire substrates. The periodicity of the films is in the range 10-500 nm. The overall composition of the films are 1/3, 2/1, and 3/1 Nb/Al, corresponding to the stoichiometric composition of the three intermetallic phases in this system.Figure 1 is a TEM micrograph of an as-deposited film with periodicity A = dA1 + dNb = 72 nm, where d's are layer thicknesses. The polycrystalline nature of the Al and Nb layers with their columnar grain structure is evident in the figure. Both Nb and Al layers exhibit crystallographic texture, with the electron diffraction pattern for this film showing stronger diffraction spots in the direction normal to the multilayer. The X-ray diffraction patterns of all films are dominated by the Al(l 11) and Nb(l 10) peaks and show a merging of these two peaks with decreasing periodicity.

scholarly journals Microstructural Development in a TRIP-780 Steel Joined by Friction Stir Welding (FSW): Quantitative Evaluations and Comparisons with EBSD Predictions

2016 ◽  
Vol 21 (2) ◽  
pp. 146-155 ◽  
Author(s):  
Gladys Perez Medina ◽  
Hugo Lopez Ferreira ◽  
Patricia Zambrano Robledo ◽  
Argelia Miranda Pérez ◽  
Felipe A. Reyes Valdés
Keyword(s):  
Retained Austenite ◽  
Shear Fracture ◽  
Grain Structure ◽  
Microstructural Development ◽  
Grain Texture ◽  
X Ray Diffraction ◽  
Significant Drop ◽  
X Ray ◽  
Friction Stir ◽  
Lap Shear

Abstract The present work describes the effect of FSW on the result microstructure in the stir zone (SZ), thermo-mechanically affected zone (TMAZ), heat affected zone (HAZ) and base metal (BM) of a TRIP-780 steel. X-ray diffraction (XRD), optical microscopy (OM) and EBSD were used for determinations retained austenite (RA) in the SZ, It was found that the amount of RA developed in SZ was relatively large, (approximately 11% to 15%). In addition, recrystallization and the formation of a grain texture were resolved using EBSD. During FSW, the SZ experienced severe plastic deformation which lead to an increase in the temperature and consequently grain recrystallization. Moreover, it was found that the recrystallized grain structure and relatively high martensite levels developed in the SZ lead to a significant drop in the mechanical properties of the steel. In addition, microhardness profiles of the welded regions indicated that the hardness in both the SZ and TMAZ were relatively elevated confirming the development of martensite in these regions. In particular, to evaluate the mechanical strength of the weld, lap shear tensile test was conducted; exhibited the fracture zone in the SZ with shear fracture with uniformly distributed elongation shear dimples.

Effect of Annealing Temperature and External Tensile Stress on Negative Thermal Expansion to Cold Rolled Ti–23Nb–0.7Ta–2Zr Alloy

2020 ◽  
Vol 12 (9) ◽  
pp. 1409-1412
Author(s):  
Jeong-Tae Moon ◽  
Tae-Hyun Nam
Keyword(s):  
Thermal Expansion ◽  
Annealing Temperature ◽  
Negative Thermal Expansion ◽  
Constant Load ◽  
External Stress ◽  
Expansion Rate ◽  
X Ray Diffraction ◽  
X Ray ◽  
Cold Rolled ◽  
The Difference

The effect of annealing temperature and external stress on the thermal expansion of a Ti–23Nb–0.7Ta–2Zr alloy were investigated by means of thermal expansion tests under constant load and X-ray diffraction (XRD). Negative thermal expansion (NTE), which is a shrinkage during heating, was observed in both a cold rolled and annealed specimens. The intensity of (200)β peak decreased while that of (211)β peak increased as the annealing temperature increased. The difference in expansion rate between 50 °C and 250 °C is found to decrease with an increasing annealing temperature from 600 °C to 800 °C, above which it kept almost constant. The expansion rate decreased as the applied stress increased.

Neutron and X-Ray Diffraction Analysis of Residual Stresses in Cold-Rolled Pearlitic Steel Sheet

2006 ◽  
pp. 375-380
Author(s):  
Marc Seefeldt ◽  
Artur Walentek ◽  
Paul Van Houtte ◽  
Miroslav Vrána ◽  
Petr Lukáš
Keyword(s):  
Residual Stresses ◽  
Diffraction Analysis ◽  
Steel Sheet ◽  
Pearlitic Steel ◽  
X Ray Diffraction ◽  
X Ray ◽  
Cold Rolled

Measurements of lattice strain in cold-rolled CR4 steel sheets using X-ray diffraction

2021 ◽  
Vol 264 ◽  
pp. 114930
Author(s):  
Tilak Raj Gupta ◽  
Sarabjeet Singh Sidhu ◽  
Jitendra Kumar Katiyar ◽  
H.S. Payal
Keyword(s):  
Lattice Strain ◽  
X Ray Diffraction ◽  
X Ray ◽  
Steel Sheets ◽  
Cold Rolled

scholarly journals Evaluation of Internal Stress in Individual Grains of Cold-Rolled Stainless Steel by Energy Dispersive X-ray Diffraction

2013 ◽  
Vol 53 (1) ◽  
pp. 165-169 ◽  
Author(s):  
Kentaro Kajiwara ◽  
Masugu Sato ◽  
Tamotsu Hashimoto ◽  
Takuyo Yamada ◽  
Takumi Terachi ◽  
...  
Keyword(s):  
Stainless Steel ◽  
Internal Stress ◽  
Energy Dispersive ◽  
X Ray Diffraction ◽  
X Ray ◽  
Cold Rolled ◽  
Individual Grains

Amorphous Solids, Small Particles and Thin Surface Films

1957 ◽  
Vol 1 ◽  
pp. 73-99 ◽  
Author(s):  
F. Schossberger
Keyword(s):  
Electroless Nickel ◽  
Surface Films ◽  
Fibrous Materials ◽  
X Ray Diffraction ◽  
Surface Layers ◽  
X Ray ◽  
Cold Rolled ◽  
Combination Of Methods ◽  
Diffraction Effects ◽  
The Relationship

AbstractA comprehensive chart is preserit of the X-ray diffraction effects of gas-and Uquid-like armorphous substances, small particle-size materials, mixtures of amorphous and crystalline compounds, sheetlike crystals, and fibrous materials.The relationship between the X-ray diagrams and chemical preparations as shown by typical examples from the field of the manufacture of active catalysts cadmium sulfide semiconductors, pour point-depressed lubricants, electroless nickel platings and metal-filled cellulose fibers.The investigation of thin surface layers formed by chemical reactions required the combination of electron and X-ray diffraction techniques. The usefulness of this combination of methods is demonstrated by a study of black stain formation on cold rolled annealed steel. By identifying the materials in the stain and determining the sequence in which they formed a reaction mechanism between steel surface and annealing-gas can be postulated.

Effect of Sintering Temperature on Silver-Copper Nanopaste as High Temperature Die Attach Material

2013 ◽  
Vol 795 ◽  
pp. 47-50 ◽  
Author(s):  
Kim Seah Tan ◽  
Kuan Yew Cheong
Keyword(s):  
Electrical Conductivity ◽  
High Temperature ◽  
Sintering Temperature ◽  
Grain Structure ◽  
Binder System ◽  
X Ray Diffraction ◽  
X Ray ◽  
Silver Copper ◽  
Die Attach ◽  
Scanning Electron

A novel stencil-printable silver-copper (Ag-Cu) nanopaste that serves as an alternative high temperature die attach material was introduced in this study. The nanopaste was made by mixing 50 nm-sized of Ag and Cu particles with an organic binder system. Sintering temperatures, up to 450°C, were used to sinter nanopaste in air and its post sintered properties were investigated. The viscosity of nanopaste was 350,000 cps and it demonstrated a shear thinning behavior. Scanning electron microscope revealed the change of grain structure with the change in the sintering temperature. Formations of Ag97Cu3 and Ag1Cu99 compounds after sintering were confirmed with X-ray diffraction; and the electrical conductivity of the sintered nanopaste was increased with the increase of the sintering temperature. The study concluded 380°C was the optimum sintering temperature to form a well sintered nanopaste.

Texture Development in a Special Rolled AA6016 Aluminum Alloy

2013 ◽  
Vol 834-836 ◽  
pp. 416-419
Author(s):  
Tong He ◽  
Ning Zhang ◽  
Wei Sun
Keyword(s):  
Aluminum Alloy ◽  
Reference Frame ◽  
Rolling Texture ◽  
Texture Development ◽  
X Ray Diffraction ◽  
Deformation Method ◽  
X Ray ◽  
Cold Rolled

AA6016 aluminum alloy with a strong β fiber rolling texture was cold rolled to different reductions by means of a special deformation method (side rolling in Chinese). The texture development during side rolling was investigated by X-ray diffraction. The typical B, S and C orientation on the β fiber are transformed into the B'{111}, S'{22 17 9} and C'{011} orientations, respectively. The results show that these orientations are unstable and gradually rotate to the B orientation in the new sample reference frame.

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