Phase diagram studies in the quasi binary systems LaMnO3–SrMnO3 and LaMnO3–CaMnO3

2000 ◽  
Vol 15 (5) ◽  
pp. 1161-1166 ◽  
Author(s):  
Peter Majewski ◽  
Lars Epple ◽  
Michael Rozumek ◽  
Heike Schluckwerder ◽  
Fritz Aldinger
Keyword(s):  
Phase Diagram ◽  
Solid Solution ◽  
Binary Systems ◽  
Single Phase ◽  
Miscibility Gap ◽  
Structure Transformation

The quasi binary systems LaMnO3–SrMnO3 and LaMnO3–CaMnO3 were studied. Both systems show a miscibility gap at intermediate La:Sr and La:Ca ratios below about 1400 °C in air. This phenomenon causes the decomposition of single-phase (La,Sr)MnO3−x and (La,Ca)MnO3−x solid solution into La-rich SrMnO3−x + Sr-rich LaMnO3−x and La-rich CaMnO3−x + Ca-rich LaMnO3−x at lower temperatures, respectively. At 1400 °C in the system LaMnO3–SrMnO3, a structure transformation of (La,Sr)MnO3 from orthorhombic to rhombohedral with increasing Sr content was not observed, and the structure of La0.7Sr0.3MnO3 was determined to be orthorhombic with a = 0.54927 ± 0.0009 nm, b = 0.54582 ± 0.0009 nm, and c 4 0.76772 ± 0.0034 nm.

Phase Equilibrium Diagrams of the Binary Systems LaMnO3-SrMnO3 and LaMnO3-CaMnO3

1999 ◽  
Vol 602 ◽  
Author(s):  
Peter Majewski ◽  
Lars Epple ◽  
Heike Schluckwerder ◽  
Fritz Aldinger
Keyword(s):  
Solid Solution ◽  
Phase Equilibrium ◽  
Binary Systems ◽  
Single Phase ◽  
Miscibility Gap ◽  
Structure Transformation

AbstractThe quasi binary systems LaMnO3 – SrMnO3 and LaMnO3 – CaMnO3 have been studied. Both systems show a miscibility gap below about 1400°C in air. This phenomenon causes the decomposition of single phase (La,Sr)MnO3−x and (La,Ca)MnO3−x solid solution with intermediate La:Sr or La:Ca ratios into La rich SrMnO3−x or CaMnO3−x and Sr or Ca rich LaMnO3−x at lower temperatures. At 1400°C a structure transformation of (La,Sr)MnO3 from orthorhombic to rombohedral has not been observed and the structure of La0.7Sr0.3MnO3 has been determined to be orthorhombic with a = 0.54927 ± 0.0009 nm, b = 0.54582 ± 0.0009 nm, and c = 0.76772 ± 0.0034 nm.

Phase-Field Modelling of radiation induced microstructures

2015 ◽  
Vol 1743 ◽  
Author(s):  
L. Luneville ◽  
G. Demange ◽  
V. Pontikis ◽  
D. Simeone
Keyword(s):  
Phase Diagram ◽  
Phase Field ◽  
Binary Systems ◽  
Canonical Ensemble ◽  
Excess Free Energy ◽  
Equilibrium Phase ◽  
Equilibrium Phase Diagram ◽  
Miscibility Gap ◽  
Radiation Induced ◽  
Grand Canonical

ABSTRACTThis work shows that realistic irradiation-induced phase separation and the resulting microstructures can be obtained via an adapted Phase Field (PF) modelling combined with atomistic Monte Carlo simulations in the pseudo-grand canonical ensemble. The last allow for calculating the equilibrium phase diagram of the silver-copper alloy, chosen as a model of binary systems with large miscibility gap and, for extracting the parameters of the excess free-energy PF functional. Relying on this methodology, the equilibrium phase diagram of the alloy is predicted in excellent agreement with its experimental counterpart whereas, under irradiation, the predicted microstructures are functions of the irradiation parameters. Different irradiation conditions trigger the formation of various microstructures consistently presented as a non-equilibrium “phase diagram” aiming at facilitating the comparison with experimental observations.

scholarly journals Phase equilibria in the YFeO3 – YСoO3 system in air

2021 ◽  
Vol 8 (1) ◽  
pp. 20218108
Author(s):  
A. V. Bryuzgina ◽  
A. S. Urusova ◽  
I. L. Ivanov ◽  
V. A. Cherepanov
Keyword(s):  
Phase Diagram ◽  
Solid Solution ◽  
Phase Equilibria ◽  
Spin State ◽  
Solid Solutions ◽  
Homogeneity Range ◽  
Perovskite Structure ◽  
Single Phase ◽  
Decomposition Temperature ◽  
Unusual Behavior

YFe1-xСоxO3 solid solutions were prepared by glycerol-nitrate technique. The homogeneity range of solid solutions was studied within the temperature range 1173 – 1573 K. A continues series of solid solution below the decomposition temperature of YСоO3, which was shown to be equal to 1266 ± 6 K, begins to narrow at higher temperatures and becomes equal to 0 ≤ x ≤ 0.1 at 1573 K. The phase diagram of the YFeO3 – YСoO3 system in the “T – composition” coordinates was divided into three fields. Similar to the parent ternary oxides, all single-phase YFe1-xСоxO3 solid solutions possess orthorhombically distorted perovskite structure (Pnma space group). Unusual behavior of orthorhombic distortions in YFe1-xСоxO3 with temperature was explained by probable changes in spin state of Co3+ ions.

The C14-to-C15 Transformation in Cr2Hf

1994 ◽  
Vol 364 ◽  
Author(s):  
K. S. Kumar ◽  
P. M. Hazzledine
Keyword(s):  
Heat Treatment ◽  
Phase Diagram ◽  
Solid Solution ◽  
Elevated Temperature ◽  
Room Temperature ◽  
Single Phase ◽  
Higher Order ◽  
Two Phase ◽  
Heat Treated ◽  
Order Structures

AbstractThree alloys, single-phase Cr2Hf, a two-phase alloy consisting of Cr solid solution and Cr2Hf, and a two-phase alloy consisting of Hf solid solution and Cr2Hf were cast and heat treated. The C14-to- C15 transformation of the Laves phase, Cr2Hf was studied as a function of heat treatment. According to the existing phase diagram, the Cr2Hf phase exhibits a C14 structure at elevated temperature but transforms to the C15 structure at lower temperatures. Such transformations are known to be extremely sluggish. In the present study, the Cr2Hf phase was found to retain the C14 structure at room temperature in all three compositions in the cast or cast and forged conditions; upon subsequent heat-treatment at various temperatures and time-at-temperatures, however, the C14 structure decomposes to a variety of higher order structures including the 16H, 10H, and 4H structures. These superstructures can be viewed as containing various percentages of the cubic and hexagonal stacking. The C15 structure was not observed for any of the conditions considered.

Nano-Size and Miscibility Gap

2012 ◽  
Vol 585 ◽  
pp. 8-13 ◽  
Author(s):  
Chandan Srivastava
Keyword(s):  
Solid Solution ◽  
Phase Stability ◽  
Research Group ◽  
Binary Systems ◽  
Miscibility Gap ◽  
Research Activities ◽  
Work Done ◽  
Nano Size

Reports on the alloys formed from immiscible atoms when they are contained in a nano-sized system have initiated several research activities in the recent years. Bridging of the miscibility gap at nanoscale is significant as it has the potential to produce novel alloy materials with useful technological applications. Although the literature contains noticeable number of reports on the formation of solid solution between bulk immiscible atoms, several issues related to phase stability and microstructure remain unaddressed. This article discusses some of these issues using examples from the work done by the author’s research group on isolated nanoparticles of bulk immiscible binary systems such as Ag-Ni, Ag-Fe and Ag-Co.

Transition alpha structure in beta-isomorphous Nb-Hf alloys

1987 ◽  
Vol 45 ◽  
pp. 232-233
Author(s):  
R.W. Carpenter ◽  
Changhai Li ◽  
David J. Smith
Keyword(s):  
Solid Solution ◽  
Solution Phase ◽  
Miscibility Gap ◽  
Large Strains ◽  
Solid Solution Phase ◽  
Two Phase ◽  
Diffuse Intensity ◽  
Metastable Form ◽  
The Matrix ◽  
Equilibrium Morphology

Binary Nb-Hf alloys exhibit a wide bcc solid solution phase field at temperatures above the Hfα→ß transition (2023K) and a two phase bcc+hcp field at lower temperatures. The β solvus exhibits a small slope above about 1500K, suggesting the possible existence of a miscibility gap. An earlier investigation showed that two morphological forms of precipitate occur during the bcc→hcp transformation. The equilibrium morphology is rod-type with axes along <113> bcc. The crystallographic habit of the rod precipitate follows the Burgers relations: {110}||{0001}, <112> || <1010>. The earlier metastable form, transition α, occurs as thin discs with {100} habit. The {100} discs induce large strains in the matrix. Selected area diffraction examination of regions ∼2 microns in diameter containing many disc precipitates showed that, a diffuse intensity distribution whose symmetry resembled the distribution of equilibrium α Bragg spots was associated with the disc precipitate.

Using phase boundary mapping to resolve discrepancies in the Mg2Si–Mg2Sn miscibility gap

2021 ◽  
Author(s):  
Rachel Orenstein ◽  
James P. Male ◽  
Michael Toriyama ◽  
Shashwat Anand ◽  
G. Jeffrey Snyder
Keyword(s):  
Phase Diagram ◽  
Phase Boundary ◽  
Ternary Phase ◽  
Ternary Phase Diagram ◽  
Miscibility Gap ◽  
Boundary Mapping

A new understanding of the MgSi–MgSn miscibility gap is reached through phase boundary mapping the Mg–Si–Sn ternary phase diagram.

A review on phase prediction in high entropy alloys

2021 ◽  
pp. 095440622110089
Author(s):  
Vinay Kumar Soni ◽  
S Sanyal ◽  
K Raja Rao ◽  
Sudip K Sinha
Keyword(s):  
Solid Solution ◽  
Phase Formation ◽  
Single Phase ◽  
High Entropy Alloy ◽  
High Entropy Alloys ◽  
Modeling Tools ◽  
High Entropy ◽  
Recent Developments ◽  
Phase Prediction ◽  
The Stability

The formation of single phase solid solution in High Entropy Alloys (HEAs) is essential for the properties of the alloys therefore, numerous approach were proposed by many researchers to predict the stability of single phase solid solution in High Entropy Alloy. The present review examines some of the recent developments while using computational intelligence techniques such as parametric approach, CALPHAD, Machine Learning etc. for prediction of various phase formation in multicomponent high entropy alloys. A detail study of this data-driven approaches pertaining to the understanding of structural and phase formation behaviour of a new class of compositionally complex alloys is done in the present investigation. The advantages and drawbacks of the various computational are also discussed. Finally, this review aims at understanding several computational modeling tools complying the thermodynamic criteria for phase formation of novel HEAs which could possibly deliver superior mechanical properties keeping an aim at advanced engineering applications.

Sign in / Sign up

Export Citation Format

Share Document