scholarly journals A Comparative Study of Short Range Order in Fe-Cr and Fe-V Alloys Around Equiatomic Composition

1990 ◽  
Vol 213 ◽  
Author(s):  
P.E.A. Turchi ◽  
M. Sluiter ◽  
G. M. Stocks
Keyword(s):  
High Temperature ◽  
First Principles ◽  
Driving Force ◽  
Short Range ◽  
Short Range Order ◽  
Electronic Band Structure ◽  
Range Order ◽  
Ordered Structure ◽  
Structure Approach ◽  
Electronic Band

ABSTRACTConfigurational energies have been calculated for equiatomic Fe-Cr and Fe-V alloys possessing the high temperature bcc crystalline structure, within a first principles electronic band structure approach. In agreement with experimental facts, a tendency towards order, with a B2 ordered structure of CsCI type, is found for FeV whereas phase separation characterizes FeCr. These results suggest that the nature of short range order in the high temperature bcc solid solution is not the primary driving force for describing the structural transformation from bcc to sigma which takes place in both alloys upon decreasing temperature.

scholarly journals Mathematical model of high-temperature melt flow with account for short-range order nature

2019 ◽  
Vol 94 (2) ◽  
pp. 22-28
Author(s):  
S.N. Shaltakov ◽  
◽  
S.Sh. Kazhikenova ◽  
B.R. Nussupbekov ◽  
D.Zh. Karabekova ◽  
...  
Keyword(s):  
Mathematical Model ◽  
High Temperature ◽  
Short Range ◽  
Short Range Order ◽  
Range Order ◽  
Melt Flow

HREM and Image Simulation of Short-Range-Order Domains in Ion Irradiated Zirconolite

2000 ◽  
Vol 6 (S2) ◽  
pp. 392-393
Author(s):  
S. X. Wang ◽  
L. M. Wang ◽  
R. C. Ewing
Keyword(s):  
High Temperature ◽  
Critical Temperature ◽  
Temperature Dependence ◽  
Short Range ◽  
Radiation Effects ◽  
Short Range Order ◽  
Fluorite Structure ◽  
Range Order ◽  
Image Simulation ◽  
Ion Species

Zirconolite (CaZrTi2O7) is an important phase proposed for immobilization of plutonium. Radiation effects in zirconolite were studied by 1 MeV Kr+ and 1.5 MeV Xe+ irradiation at various temperatures. Zirconolite became amorphous at temperatures below a critical temperature, Tc. The critical temperature was found to be a function of ion species: Tc - 654 K for 1 MeV Kr+ and 710 K for 1.5 MeV Xe+. The temperature dependence of amorphization dose is shown in FIG. 1. Above Tc, the specimen remained crystalline after prolonged irradiation (up to 3.6×l015 ions/cm2). However, the high-temperature irradiated zirconolite was transformed into the fluorite structure (as shown by the strong diffraction maxima in FIG. 2). In addition to the maxima from the fluorite structure, strong diffuse maxima were observed surrounding the Bragg position of pyrochlore superlattice (FIG. 2).

scholarly journals Magnetically driven short-range order can explain anomalous measurements in CrCoNi

2021 ◽  
Vol 118 (13) ◽  
pp. e2020540118
Author(s):  
Flynn Walsh ◽  
Mark Asta ◽  
Robert O. Ritchie
Keyword(s):  
First Principles ◽  
Short Range ◽  
Short Range Order ◽  
Nearest Neighbor ◽  
Range Order ◽  
Magnetic Interactions ◽  
First Principles Calculations ◽  
Principal Element ◽  
The Impact ◽  
Magnetically Aligned

The presence, nature, and impact of chemical short-range order in the multi-principal element alloy CrCoNi are all topics of current interest and debate. First-principles calculations reveal that its origins are fundamentally magnetic, involving repulsion between like-spin Co–Cr and Cr–Cr pairs that is complemented by the formation of a magnetically aligned sublattice of second-nearest-neighbor Cr atoms. Ordering models following these principles are found to predict otherwise anomalous experimental measurements concerning both magnetization and atomic volumes across a range of compositions. In addition to demonstrating the impact of magnetic interactions and resulting chemical rearrangement, the possible explanation of experiments would imply that short-range order of this type is far more prevalent than previously realized.

Simulation of Atomic Configurations in Short Range Ordered Ni3Fe

1982 ◽  
Vol 21 ◽  
Author(s):  
F. Bley ◽  
P. Cenedese ◽  
S. Lefevbre
Keyword(s):  
Short Range ◽  
Short Range Order ◽  
Heat Treatments ◽  
Order Parameters ◽  
Range Order ◽  
Ordered Structure ◽  
Antiphase Boundaries

ABSTRACTA procedure similar to that of Gehlen and Cohen and Williams is used to simulate atomic configurations of short range ordered Ni3Fe. The short range order parameters were previously measured after different heat treatments. Probabilities of different clusters are computed from those models : triangles, tetrahedrons, clusters as defined by Clapp.These probabilities vary with the enhancement of short range order. It is shown that most of the clusters the probabilities of which increase with short range order, are directly related with the L12 ordered structure: either they have the L12 structure, or the L12 structure modified by one or two antiphase boundaries. Such clusters are identified in the model in order to display perfectly ordered domains.

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