Ordered γ-brass structures coexisting with the decagonal quasicrystal in a Ga46Fe23Cu23Si8 alloy

1999 ◽  
Vol 14 (7) ◽  
pp. 2799-2805 ◽  
Author(s):  
S. P. Ge ◽  
K. H. Kuo
Keyword(s):  
Electron Diffraction ◽  
Orientation Relationship ◽  
Face Centered Cubic ◽  
Body Centered Cubic ◽  
Decagonal Quasicrystal ◽  
Parallel Orientation ◽  
Fundamental Structure ◽  
Lattice Correspondence ◽  
Face Centered ◽  
Rapidly Solidified

In a moderately rapidly solidified Ga46Fe23Cu23Si8 alloy, a face-centered-cubic (fcc) superstructure (a = 1.78 nm) and a hexagonal superstructure (ahex = 2.18 nm and chex = 0.77 nm), based on the same body-centered-cubic (bcc) γ-brass structure (a = 0.89 nm), were found—by means of micro-area electron diffraction—to coexist with the decagonal quasicrystal. The fcc superstructure is probably similar to one of the F-centered-γ-brass structure and has a parallel orientation relationship with the bcc fundamental structure. The hexagonal superstructure has its (001) parallel to the (111) of the bcc γ-brass structure and its chex = abcc[111]/2, and their lattice correspondence relationship has been derived. Electron diffraction evidence is presented to show that these two superstructures are possibly crystalline approximants of the decagonal quasicrystal.

scholarly journals Effects of C Addition on the Microstructures of As-Cast Cu–Fe–P Alloys

Materials ◽  
2019 ◽  
Vol 12 (17) ◽  
pp. 2772 ◽  
Author(s):  
Chen ◽  
Hu ◽  
Guo ◽  
Zou ◽  
Liu ◽  
...  
Keyword(s):  
Orientation Relationship ◽  
Supersaturated Solid Solution ◽  
Face Centered Cubic ◽  
Body Centered Cubic ◽  
Matrix Microstructure ◽  
The Matrix ◽  
Bcc Structure ◽  
The Difference ◽  
Face Centered ◽  
Fcc Structure

Effects of C addition on the microstructures of as-cast Cu–Fe–P (mass fraction) alloys were systematically investigated. The results show that C addition can refine the matrix microstructure and make Fe particles finer. The Fe particles observed in both the non-C-alloyed and C-alloyed specimens are α-Fe particles, which possess a body-centered cubic (bcc) structure with a Nishiyama–Wassermann orientation relationship with the matrix. C is reported to be an γ-Fe stabilizer in the literature. The reason for the difference between the phases of Fe particles observed in this study, and that reported in the literature, are finally discussed. Additionally, C addition facilitates the decomposition of the supersaturated solid solution which occurs by the simultaneous precipitation of very fine Fe particles. Such initial decomposition product has an face-centered cubic (fcc) structure with a cube-on-cube orientation relationship with the matrix.

Voids in Irradiated Tungsten and Molybdenum

1969 ◽  
Vol 27 ◽  
pp. 190-191
Author(s):  
Robert C. Rau ◽  
Robert L. Ladd
Keyword(s):  
Melting Point ◽  
Fast Neutron ◽  
Neutron Irradiation ◽  
Elevated Temperatures ◽  
Irradiation Temperature ◽  
The Body ◽  
Face Centered Cubic ◽  
Body Centered Cubic ◽  
Cubic Metals ◽  
Face Centered

Recent studies have shown the presence of voids in several face-centered cubic metals after neutron irradiation at elevated temperatures. These voids were found when the irradiation temperature was above 0.3 Tm where Tm is the absolute melting point, and were ascribed to the agglomeration of lattice vacancies resulting from fast neutron generated displacement cascades. The present paper reports the existence of similar voids in the body-centered cubic metals tungsten and molybdenum.

Electron diffraction detection of ordliking in annealed PbTe thin film

1990 ◽  
Vol 48 (4) ◽  
pp. 1018-1019
Author(s):  
Karimat El-Sayed
Keyword(s):  
Thin Film ◽  
Electron Diffraction ◽  
Lead Telluride ◽  
Structural Basis ◽  
Face Centered Cubic ◽  
X Ray ◽  
Polycrystalline Thin Films ◽  
Stage Process ◽  
Diffraction Patterns ◽  
Face Centered

Lead telluride is an important semiconductor of many applications. Many Investigators showed that there are anamolous descripancies in most of the electrophysical properties of PbTe polycrystalline thin films on annealing. X-Ray and electron diffraction studies are being undertaken in the present work in order to explain the cause of this anamolous behaviour.Figures 1-3 show the electron diffraction of the unheated, heated in air at 100°C and heated in air at 250°C respectively of a 300°A polycrystalline PbTe thin film. It can be seen that Fig. 1 is a typical [100] projection of a face centered cubic with unmixed (hkl) indices. Fig. 2 shows the appearance of faint superlattice reflections having mixed (hkl) indices. Fig. 3 shows the disappearance of thf superlattice reflections and the appearance of polycrystalline PbO phase superimposed on the [l00] PbTe diffraction patterns. The mechanism of this three stage process can be explained on structural basis as follows :

scholarly journals Irradiation Behaviors in BCC Multi-Component Alloys with Different Lattice Distortions

Metals ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 706
Author(s):  
Yue Su ◽  
Songqin Xia ◽  
Jia Huang ◽  
Qingyuan Liu ◽  
Haocheng Liu ◽  
...  
Keyword(s):  
Single Phase ◽  
Vacuum Arc ◽  
Face Centered Cubic ◽  
Body Centered Cubic ◽  
Chemical Complexity ◽  
Arc Melting ◽  
Vacuum Arc Melting ◽  
Lattice Distortions ◽  
Face Centered ◽  
Displacement Per Atom

Recently, the irradiation behaviors of multi-component alloys have stimulated an increasing interest due to their ability to suppress the growth of irradiation defects, though the mostly studied alloys are limited to face centered cubic (fcc) structured multi-component alloys. In this work, two single-phase body centered cubic (bcc) structured multi-component alloys (CrFeV, AlCrFeV) with different lattice distortions were prepared by vacuum arc melting, and the reference of α-Fe was also prepared. After 6 MeV Au ions irradiation to over 100 dpa (displacement per atom) at 500 °C, the bcc structured CrFeV and AlCrFeV exhibited significantly improved irradiation swelling resistance compared to α-Fe, especially AlCrFeV. The AlCrFeV alloy possesses superior swelling resistance, showing no voids compared to α-Fe and CrFeV alloy, and scarce irradiation softening appears in AlCrFeV. Owing to their chemical complexity, it is believed that the multi-component alloys under irradiation have more defect recombination and less damage accumulation. Accordingly, we discuss the origin of irradiation resistance and the Al effect in the studied bcc structured multi-component alloys.

MINIMAL KNOTTING NUMBERS

2009 ◽  
Vol 18 (08) ◽  
pp. 1159-1173 ◽  
Author(s):  
CASEY MANN ◽  
JENNIFER MCLOUD-MANN ◽  
RAMONA RANALLI ◽  
NATHAN SMITH ◽  
BENJAMIN MCCARTY
Keyword(s):  
The Body ◽  
Computer Algorithm ◽  
Face Centered Cubic ◽  
Body Centered Cubic ◽  
Cubic Lattice ◽  
The Face ◽  
Face Centered ◽  
Body Centered Cubic Lattice

This article concerns the minimal knotting number for several types of lattices, including the face-centered cubic lattice (fcc), two variations of the body-centered cubic lattice (bcc-14 and bcc-8), and simple-hexagonal lattices (sh). We find, through the use of a computer algorithm, that the minimal knotting number in sh is 20, in fcc is 15, in bcc-14 is 13, and bcc-8 is 18.

Poisson's Ratio for Central-Force Polycrystals

1976 ◽  
Vol 31 (12) ◽  
pp. 1539-1542 ◽  
Author(s):  
H. M. Ledbetter
Keyword(s):  
Electron Energy ◽  
Poisson Ratio ◽  
The Body ◽  
Central Force ◽  
Face Centered Cubic ◽  
Polycrystalline Aggregate ◽  
Body Centered Cubic ◽  
The Face ◽  
Predicted Values ◽  
Face Centered

Abstract The Poisson ratio υ of a polycrystalline aggregate was calculated for both the face-centered cubic and the body-centered cubic cases. A general two-body central-force interatomatic potential was used. Deviations of υ from 0.25 were verified. A lower value of υ is predicted for the f.c.c. case than for the b.c.c. case. Observed values of υ for twenty-three cubic elements are discussed in terms of the predicted values. Effects of including volume-dependent electron-energy terms in the inter-atomic potential are discussed.

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