scholarly journals Deformation of C15 Laves Phase Alloys

1994 ◽  
Vol 364 ◽  
Author(s):  
F. Chu ◽  
D.P Pope
Keyword(s):  
Phase Diagram ◽  
Physical Properties ◽  
Mechanical Behavior ◽  
Laves Phase ◽  
Deformation Mechanisms ◽  
Laves Phases ◽  
Theoretical Approaches

AbstractDetails of the structure and previous work on the deformation of C15 Laves phases are reviewed. The phase diagram of the Hf-V-Nb system, some metallurgical and physical properties, mechanical behavior, and the deformation mechanisms of HfV2+Nb (C15 HfV2+Nb and V-rich bcc solution) are presented based on our previous work. Theoretical approaches to understanding the results of these studies are discussed.

Phase Equilibria in the Ternary Nb-Cr-Al System and Site Occupation in the Hexagonal C14 Laves Phase Nb(AlxCr1-x)2

2008 ◽  
Vol 1128 ◽  
Author(s):  
Oleg Prymak ◽  
Frank Stein ◽  
Alexander Kerkau ◽  
Alim Ormeci ◽  
Guido Michael Kreiner ◽  
...  
Keyword(s):  
Phase Diagram ◽  
Rietveld Analysis ◽  
Laves Phase ◽  
Laves Phases ◽  
Extended Phase ◽  
Isothermal Sections ◽  
Site Occupation ◽  
Phase Fields ◽  
The Stability ◽  
Structure Calculations

AbstractThe ternary Nb-Cr-Al phase diagram exhibits extended phase fields of the cubic C15 and the hexagonal C14 Laves phases Nb(AlxCr1-x)2. A number of Nb-Cr-Al alloys were prepared by levitation melting and annealed at temperatures between 1150 and 1450 °C for up to 1500 h. Isothermal sections of the ternary Nb-Cr-Al phase diagram at 1150, 1300 and 1450 °C were obtained from electron probe microanalysis, X-ray powder diffraction and metallographic investigations in order to study the effect of Al on the stability and structure of the Laves phases. The C14 Laves phase in the Nb-Cr-Al system can dissolve up to 45 at.% Al by substituting Cr with Al on the two different crystallographic B-sites 2a and 6h of the C14 AB2 unit cell. The site occupations of the Al and Cr atoms on these two B-sites were determined by Rietveld analysis using the program FullProf. The experimental site occupation factors were compared to site occupation factors computed by a statistical mechanics approach based on first-principles electronic structure calculations. The experimental as well as the calculated site occupation factors indicate a preferred occupation of the 2a site by Al.

The New Laves Phase Na2Ba

1994 ◽  
Vol 49 (2) ◽  
pp. 189-192 ◽  
Author(s):  
G. Jeffrey Snyder ◽  
Arndt Simon
Keyword(s):  
Crystal Structure ◽  
Phase Diagram ◽  
Single Crystal ◽  
Diffraction Data ◽  
Laves Phase ◽  
X Ray Diffraction ◽  
Laves Phases ◽  
X Ray ◽  
Strain Parameter

Abstract The crystal structure of Na2Ba was determined from single crystal X-ray diffraction data. It is isostructural with the hexagonal Laves phase Zn2Mg; P63/mmc, a = 739.3(4) pm, c = 1199.9(9) pm. The compound Na4Ba reported in the phase diagram literature is actually Na2Ba. Comparisons are made with other Laves phases using a strain parameter diagram.

Deformation modes in Laves phase intermetallics

1989 ◽  
Vol 47 ◽  
pp. 318-319
Author(s):  
Ernest L. Hall ◽  
James D. Livingston
Keyword(s):  
Mechanical Behavior ◽  
Room Temperature ◽  
Structural Complexity ◽  
Atomic Layer ◽  
Laves Phase ◽  
Intermetallic Alloys ◽  
Laves Phases ◽  
Special Mode ◽  
Cooperative Movement ◽  
Deformation Modes

There is at present a large amount of interest in the mechanical behavior of intermetallic alloys, and one of the largest classes of these alloys are the Laves phases. There are three basic types of Laves phases: cubic (C15), hexagonal (C14), and dihexagonal (C36), with stacking sequences on the close-packed planes of ABCABC..., ABAB..., and ABAC..., respectively, where each capital letter represents an interpenetrating four-atomic-layer unit. This structural complexity gives rise to a special mode of deformation for Laves phases, called synchroshear, which requires the cooperative movement of adjacent layers in different directions. Very little work has been done to date on the deformation modes in Laves phases because of the inherent brittleness of these materials at room temperature. However, through alloying it is possible to obtain mixtures of the various Laves phase types, and to affect such properties as stacking fault energy, and thus opportunities may exist for increasing ductility. In this study, the deformation microstructures of different Laves phase types were explored.

Calculation of physical properties of glass via the phase diagram approach

2017 ◽  
Vol 457 ◽  
pp. 36-43 ◽  
Author(s):  
Q.Y. Zhang ◽  
W.J. Zhang ◽  
W.C. Wang ◽  
Z.H. Jiang
Keyword(s):  
Phase Diagram ◽  
Physical Properties ◽  
Diagram Approach

Multiple Superconducting Phases in UTe2: A Complex Analogy to Superfluid Phases of 3He

2021 ◽  
Vol 1 ◽  
Author(s):  
Shinsaku Kambe ◽  
Keyword(s):  
Phase Diagram ◽  
Physical Properties ◽  
Low Temperatures ◽  
Quantum Statistics ◽  
Superconducting Phases ◽  
Fermion Systems ◽  
Quantum Liquids ◽  
Wave Symmetry ◽  
Ferromagnetic Interactions ◽  
Ordered State

In quantum liquids, large differences are observed owing to differences in quantum statistics. The physical properties of liquid <sup>3</sup>He (Fermion) and <sup>4</sup>He (Boson) are considerably different at low temperatures. After the discovery of superconductivity in electron (i.e., Fermion) systems, a similar pairing ordered state was expected for <sup>3</sup>He. Remarkably, the observed ordered state of <sup>3</sup>He was more surprising than expected, multiple superfluid phases in the <em>T-P</em> phase diagram. The origin of the multiple phases was attributed to ferromagnetic interactions in the <em>p</em>-wave symmetry state.

scholarly journals Effect of Nd, Pr substitutional atoms on the magnetic and magnetostrictive properties in (Tb-Dy)(Fe-Co)2 Laves phases

2021 ◽  
Vol 2103 (1) ◽  
pp. 012196
Author(s):  
G A Politova ◽  
M A Ganin ◽  
A B Mikhailova ◽  
D A Morozov ◽  
K E Pankov ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Magnetic Properties ◽  
Laves Phase ◽  
Type Structure ◽  
Partial Substitution ◽  
Laves Phases ◽  
Temperature Range ◽  
Homogenizing Annealing ◽  
Arc Melting ◽  
Magnetostrictive Materials

Abstract Polycrystalline TbxDy1-xR0.1Fe2-zCoz (R = Nd, Pr, x = 0.2, 0.3; z = 0, 1.3) cubic Laves phase alloys with MgCu2-type structure were prepared by arc melting followed by homogenizing annealing. The crystal structure, magnetic properties, and magnetostriction have been investigated. Compounds with high values of magnetostrictive susceptibility were found in the temperature range 150-300 K. Compounds with partial substitution of cobalt for iron demonstrate a change in the sign of anisotropic magnetostriction. This work continues the search for magnetostrictive materials with inexpensive neodymium and praseodymium.

Ground-state structures, physical properties and phase diagram of carbon-rich nitride C5N

2018 ◽  
Vol 30 (38) ◽  
pp. 385402 ◽  
Author(s):  
Qinghua Wu ◽  
Qianku Hu ◽  
Yiming Hou ◽  
Haiyan Wang ◽  
Aiguo Zhou ◽  
...  
Keyword(s):  
Phase Diagram ◽  
Physical Properties ◽  
Ground State ◽  
Ground State Structures

Ternary transition metal gallides with TiNiSi, ZrBeSi and MgZn2-type structure

2019 ◽  
Vol 74 (3) ◽  
pp. 297-306 ◽  
Author(s):  
Lukas Heletta ◽  
Theresa Block ◽  
Steffen Klenner ◽  
Rainer Pöttgen
Keyword(s):  
Transition Metal ◽  
Powder Diffraction ◽  
Metallic Iron ◽  
Site Occupancy ◽  
Laves Phase ◽  
Structural Motif ◽  
Equiatomic Composition ◽  
Laves Phases ◽  
X Ray ◽  
Arc Melting

AbstractA series of ternary transition metal gallides around the equiatomic composition have been synthesized from the elements by arc-melting and subsequent annealing. The compounds crystallize with site occupancy variants of the hexagonal Laves phase MgZn2, with the hexagonal ZrBeSi or the orthorhombic TiNiSi type. All samples have been characterized on the basis of their lattice parameters, determined by X-ray powder diffraction (Guinier technique). The structures of NbCr1.58Ga0.42 and NbFe1.51Ga0.49 (MgZn2 type, P63/mmc), NbRhGa (ZrBeSi type, P63/mmc), and ScNiGa, ScPtGa and ScAuGa (TiNiSi type, Pnma) were refined from single crystal X-ray diffractometer data. The ScPtGa and ScAuGa crystals showed trilling formation. Mixed site occupancies were only observed in the Laves phases while all other crystals were well ordered. A striking structural motif of NbRhGa is the formation of niobium chains (264 pm Nb–Nb) along the c axis. Several gallides were magnetically characterized. They are Pauli paramagnets. The two crystallographically independent iron sites in the Laves phase TaFeGa could be distinguished in the 57Fe Mössbauer spectrum. The isomer shifts of 0.06(3) (Fe1) and –0.02(3) (Fe2) mm s−1 indicate metallic iron.

Sign in / Sign up

Export Citation Format

Share Document