The Measurement of Composition During the Early Stages of the Spinodal Decomposition of Fe-Cr Alloys

1990 ◽  
Vol 186 ◽  
Author(s):  
M.G. Hetherington ◽  
J.M. Hyde ◽  
M.K. Miller
Keyword(s):  
Monte Carlo ◽  
Phase Separation ◽  
Spinodal Decomposition ◽  
Atom Probe ◽  
Statistical Techniques ◽  
Fine Scale ◽  
Monte Carlo Calculations ◽  
Early Stages ◽  
Non Linear

AbstractThe properties of many advanced alloys are derived from extremely fine-scale microstructures. This poses interesting questions about the measurement of composition on this scale. The phase separation of model Fe-Cr alloys has been been studied with the atom-probe. Statistical techniques have been used to estimate the composition and compare the results with the predictions of linear and non-linear theories of spinodal decomposition and the distributions obtained from Monte-Carlo calculations.

Ordering and phase separation in Ni–Cr–Al: Monte Carlo simulations vs three-dimensional atom probe

1999 ◽  
Vol 47 (6) ◽  
pp. 1889-1899 ◽  
Author(s):  
C. Pareige ◽  
F. Soisson ◽  
G. Martin ◽  
D. Blavette
Keyword(s):  
Monte Carlo ◽  
Phase Separation ◽  
Monte Carlo Simulations ◽  
Three Dimensional ◽  
Atom Probe

Spinodal Decomposition in Fe-Cr-Co Alloys

1982 ◽  
Vol 21 ◽  
Author(s):  
S. S. Brenner ◽  
P. P. Camus ◽  
M. K. Miller ◽  
W. A. Soffa
Keyword(s):  
Phase Separation ◽  
Spinodal Decomposition ◽  
Atom Probe ◽  
Continuous Phase ◽  
Miscibility Gap ◽  
Two Phase ◽  
Probe Field ◽  
Long Wavelength ◽  
Composition Fluctuations ◽  
Kinetics Of

Continuous phase separation or spinodal decomposition occurs within a miscibility gap through the selective amplification of long wavelength concentration waves to produce a two-phase modulated microstructure. To comprehensively study the formation of these modulated microstructures and the kinetics of continuous phase separation the behavior of the composition fluctuations in the decomposing material should be monitored directly. The atom probe field-ion microscope is an ideal instrument for this type of investigation of fine-scale microstructures because of its ultra-high spatial resolution and microchemical analysis capability.

Early stages of phase separation using three-dimensional atom probe and atomistic modelling

2007 ◽  
Vol 39 (2-3) ◽  
pp. 178-183 ◽  
Author(s):  
Mattias Slabanja ◽  
Johan Angenete ◽  
Krystyna Stiller ◽  
Karin M. Carling ◽  
Göran Wahnström ◽  
...  
Keyword(s):  
Phase Separation ◽  
Three Dimensional ◽  
Atom Probe ◽  
Early Stages ◽  
Atomistic Modelling

The β'-α' Interaction: a Study of early Stages of Phase Separation in a Fe-20%Cr-6%Al-0.5%Ti Alloy

2011 ◽  
Vol 172-174 ◽  
pp. 315-320
Author(s):  
Carlos Capdevila ◽  
Michael K. Miller ◽  
K.F. Russell ◽  
J. Chao ◽  
F.A. López
Keyword(s):  
Phase Separation ◽  
Atom Probe Tomography ◽  
Temporal Evolution ◽  
Theoretical Calculations ◽  
Three Dimensional ◽  
Atom Probe ◽  
Early Stages ◽  
Β Phase ◽  
Α Phase ◽  
Power Measurements

The temporal evolution of the microstructure resulting from phase separation into Fe-rich (α), Cr-rich (α¢), and Fe(Ti,Al) (β¢) phases of a Fe-20Cr-6Al-0.5Ti alloy has been analyzed by thermoelectric power measurements (TEP). The early stages of decomposition and the evolution of the three-dimensional microstructure have been analyzed by atom probe tomography (APT). The roles of Cr, Al, and Ti during the decomposition process have been investigated in terms of solute partitioning between the phases. Analysis of proximity histograms revealed that significant Al and Ti partitioning occurs, which is consistent with theoretical calculations. The results indicate that as the α-α¢ phase separation proceeds, Al and Ti are rejected into the α phase, which causes the β¢ phase to nucleate on the surface of the α¢ phase.

scholarly journals Correlative Energy-Dispersive X-Ray Spectroscopic Tomography and Atom Probe Tomography of the Phase Separation in an Alnico 8 Alloy

2016 ◽  
Vol 22 (6) ◽  
pp. 1251-1260 ◽  
Author(s):  
Wei Guo ◽  
Brian T. Sneed ◽  
Lin Zhou ◽  
Wei Tang ◽  
Matthew J. Kramer ◽  
...  
Keyword(s):  
Phase Separation ◽  
Spinodal Decomposition ◽  
Atom Probe Tomography ◽  
Permanent Magnets ◽  
Atom Probe ◽  
Quantitative Information ◽  
Energy Dispersive ◽  
High Coercivity ◽  
Chemical Information ◽  
X Ray

AbstractAlnico alloys have long been used as strong permanent magnets because of their ferromagnetism and high coercivity. Understanding their structural details allows for better prediction of the resulting magnetic properties. However, quantitative three-dimensional characterization of the phase separation in these alloys is still challenged by the spatial quantification of nanoscale phases. Herein, we apply a dual tomography approach, where correlative scanning transmission electron microscopy (STEM) energy-dispersive X-ray spectroscopic (EDS) tomography and atom probe tomography (APT) are used to investigate the initial phase separation process of an alnico 8 alloy upon non-magnetic annealing. STEM-EDS tomography provides information on the morphology and volume fractions of Fe–Co-rich and Νi–Al-rich phases after spinodal decomposition in addition to quantitative information of the composition of a nanoscale volume. Subsequent analysis of a portion of the same specimen by APT offers quantitative chemical information of each phase at the sub-nanometer scale. Furthermore, APT reveals small, 2–4 nm Fe-rich α1 phases that are nucleated in the Ni-rich α2 matrix. From this information, we show that phase separation of the alnico 8 alloy consists of both spinodal decomposition and nucleation and growth processes. The complementary benefits and challenges associated with correlative STEM-EDS and APT are discussed.

scholarly journals Unconventional phase separation in the model 2D spin-pseudospin system

2018 ◽  
Vol 185 ◽  
pp. 11006 ◽  
Author(s):  
K.S. Budrin ◽  
Yu.D. Panov ◽  
A.S. Moskvin ◽  
A.A. Chikov
Keyword(s):  
Monte Carlo ◽  
Phase Separation ◽  
Ground State ◽  
Spin Exchange ◽  
Mean Field ◽  
Field Approximation ◽  
Mean Field Approximation ◽  
Spin Subsystem ◽  
Monte Carlo Calculations ◽  
Antiferromagnetic Ordering

The competition of charge and spin orderings is a challenging problem for strongly correlated systems, in particular, for high-Tc cuprates. We addressed a simplified static 2D spin-pseudospin model which takes into account both conventional spin exchange coupling and the on-site and inter-site charge correlations. Classical Monte-Carlo calculations for large square lattices show that homogeneous ground state antiferromagnetic solutions found in a mean-field approximation are unstable with respect to phase separation into the charge and spin subsystems behaving like immiscible quantum liquids. In this case, with lowering of a temperature one can observe two sequential phase transitions: first, antiferromagnetic ordering in the spin subsystem diluted by randomly distributed charges, then, the charge condensation in the charge droplets. The inhomogeneous droplet phase reduces the energy of the system and changes the diagram of the ground states. On the other hand, the ground state energy of charge-ordered state in a mean-field approximation exactly matches the numerical Monte-Carlo calculations. The doped charges in this case are distributed randomly over a system in the whole temperature range. Various thermodynamic properties of the 2D spin-pseudospin system are studied by Monte-Carlo simulation.

Characterization of the Early Stages of Phase Separation by Atom probe Tomography

1999 ◽  
Vol 580 ◽  
Author(s):  
M. K. Miller
Keyword(s):  
Phase Separation ◽  
Atom Probe Tomography ◽  
Atom Probe ◽  
Alloy 718 ◽  
Early Stages ◽  
Nickel Based Superalloy ◽  
Secondary Precipitates ◽  
Isothermal Ageing

AbstractAn atom probe tomography characterization of the early stages of phase separation in the FeCu-Ni system has been performed. The development of the copper-enriched regions into copper precipitates has been investigated during isothermal ageing at 573 K and 673 K for times up to 10,000 h. The formation and growth of the secondary precipitates in the nickel based superalloy, Alloy 718, have been determined during isothermal ageing at 873 K. These secondary precipitates were found to be a mixture of the L12-ordered γ' phase and the DO22-ordered γ” phase.

Early stages of spinodal decomposition for the Cahn-Hilliard-Cook model of phase separation

1988 ◽  
Vol 38 (7) ◽  
pp. 4725-4739 ◽  
Author(s):  
K. R. Elder ◽  
T. M. Rogers ◽  
Rashmi C. Desai
Keyword(s):  
Phase Separation ◽  
Spinodal Decomposition ◽  
Early Stages ◽  
Cook Model
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