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1.
Two-phase equilibria between the ferromagnetic fcc and the paramagnetic fcc phase from 800 ℃ to 900 ℃ in the Co-rich region have been detected by the diffusion couple technique. Two phase separation region of the fcc has been confirmed along the Curie temperature. The phase equilibria including the present results and the thermodynamic data of the Co-Cr system reported in the literature were analyzed on the basis of the thermodynamic evaluation. A set of thermodynarnic values for the liquid, fcc, hcp, bcc, sigma phases was obtained. The calculated phase equilibria were in good agreement with most of the experimental data. 相似文献
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N. A. Belov 《Russian Journal of Non-Ferrous Metals》2010,51(3):243-249
A quantitative analysis of the phase diagram of the Al-Zn-Mg-Cu-Ni as applied to high-strength nickalines is performed using
the Thermo-Calc program. Using the Al-6% Zn-2% Mg-4% Ni base composition as an example, it is shown that the copper addition
substantially complicates the phase composition. Exerting a weak effect on the liquidus of the base composition, copper strongly
reduces the solidus (equilibrium and nonequilibrium). On the one hand, this restricts the possibility of carrying out high-temperature
annealing; on the other hand, it can negatively affect the cast properties. By the totality of the calculated and previously
obtained experimental data, it is concluded that copper-free nickalines are preferable compared to cuprous ones. 相似文献
8.
Based on the thermodynamic principles of phase rule and heterogeneous equilibria, the ternary phase diagram for the system
Fe-SiO in the range of temperatures from 1730 to 1200° has been constructed with more attention paid to temperatures above
1515° and towards the iron corner of the diagram. The system is characterized by a region of three liquids above 1730° which
reduces to two-liquids regions at lower temperatures. Several three-phase and four-phase reactions occur in this system on
cooling, at various temperatures. Near the iron corner a eutectic reaction occurs at a fixed temperature in which delta iron
co-precipitates with cristobalite from liquid iron containing silicon and oxygen. At lower temperatures the system is characterized
by an invariant reaction involving liquid iron, delta iron, cristobalite and liquid oxide. For oxygen rich melts, solidification
terminates on the Fe-0 binary with the monotectic precipitation of delta iron and liquid oxide.
This paper was presented at the Centennial Meeting of the AIME Conference, New York, 1971. 相似文献
9.
An associated solution model is applied to describe the thermodyanmic properties of the liquid Ni-S phase. This model assumes
the existence of ‘NiS’ (l) species in the liquid in addition to Ni(l) and S(l). With two solution parameters for the binaries
Ni-‘NiS’ and ‘NiS’-S, this model is able to describe the thermodynamic behavior of the liquid phase over a wide range of temperature
and composition. Using this model for the liquid phase, a statistical thermodynamic model for the monosulfide phase and empirical
thermodynamic equations for β1-Ni3S2 and β2-Ni4S3, the Ni-S phase diagram is calculated. The calculated diagram is in excellent agreement with the available experimental data
with the exception that the eutectic composition for the equilibrium L1 + δ + η and those of the two liquids for the equilibriumL
1
+ L
2
+ η differ from the experimental data by more than 2 at. pct S.
Formerly Post-Doctorl Research Associate, University of Wisconsin-Milwaukee is now Lecturer, Department of Metallurgical Engineering,
Indian Institute of Technology, Kanpur, India 相似文献
10.
JD Franson 《Canadian Metallurgical Quarterly》1995,51(3):2371-2380
11.
Kinetics of the peritectic phase transformation: In-situ measurements and phase field modeling 总被引:1,自引:0,他引:1
Dominic Phelan Mark Reid Rian Dippenaar 《Metallurgical and Materials Transactions A》2006,37(3):985-994
An experimental study has been conducted into the role of cooling rate on the kinetics of the peritectic phase transformation
in a Fe-C alloy. The interfacial growth velocities of the peritectic phase transformation were measured in situ for cooling rates of 100, 50, and 10 K/min. In-situ observations were obtained using high-temperature laser scanning confocal microscopy (HTLSCM) in a concentric solidification
configuration. The experimentally measured interface velocities of the liquid/austenite (L/γ) and austenite/delta-ferrite
(γ/δ) interphase boundaries were observed to increase with higher cooling rates. A unique finding of this study was that as
the cooling rate increased, there was a transition point where the L/γ interface propagated at a higher velocity than the
γ/δ interface, contrary to the findings of previous researchers. Phase field modeling was conducted using a commercial multicomponent,
multiphase package. Good correlation was obtained between model predictions and experimental observations in absolute values
of interface velocities and the effect of cooling rate. Analysis of the simulated microsegregation in front of the L/γ and
γ/δ interfaces as a function of cooling rate revealed the importance of solute pileup. This microsegregation plays a pivotal
role in the propagation of interfaces; thus, earlier modeling work in which complete diffusion in the liquid phase was assumed
cannot fully describe the rate of propagation of the L/γ and δ/γ interfaces during the course of the peritectic transformation. 相似文献
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Calculation of the titanium-aluminum phase diagram 总被引:1,自引:0,他引:1
Joanne L. Murray 《Metallurgical and Materials Transactions A》1988,19(2):243-247
The Ti-Al phase diagram has been calculated by optimization of Gibbs energies with respect to phase diagram and thermochemical
data.T
0
curves, the locus of compositions and temperatures where the Gibbs energies of the liquid and one of the solid phases are
equal, have been calculated over the entire composition range. In order to assure physically reasonable extrapolations of
theT
0
curves of the ordered phases far from their equilibrium stability ranges, the Bragg-Williams approximation was used to provide
start values for the empirical optimizations. This approximation led to good convergence of the optimizations, and only small
deviations from the Bragg-Williams Gibbs energies were needed to obtain excellent agreement with experimental data. 相似文献
14.
Arthur D. Pelton 《Metallurgical and Materials Transactions A》1988,19(7):1819-1825
Several simple equations are derived which can be used to check binary phase diagrams for thermodynamic consistency. In many
cases, the only thermodynamic data required are the entropies of fusion. 相似文献
15.
FM Andrews SL White LH Williamson PL Maykuth DR Geiser EM Green SL Ralston RA Mannsman 《Canadian Metallurgical Quarterly》1995,(20):64-72
Thirty-four horses competing in the Endurance Test of a 3-day-event were divided into 3 groups: horses in Group 1 (n = 15) competing in a 3.5 min steeplechase phase; horses in Group 2 (n = 13) in a 3 min steeplechase phase (Phase B) and horses in Group 3 (n = 6) in a 2.5 min steeplechase phase. The shortening of Phase B was associated with a lengthening of Phase C so that the total distance of the event for all horses was 14,940 m. Bodyweight (BW) was measured and total body water (TBW) and water loss estimated. Blood samples were collected from the horses prior to the Endurance Test, at the end of Phase B, the 4 km marker on Phase C (C4K), the end of Phase C, and 20 min after the completion of Phase D for measurement of packed cell volume (PCV), total plasma protein [TPP], lactate, ionised calcium, pH, sodium, potassium, chloride, total calcium and glucose concentrations, and aspartate aminotransferase, creatine kinase and lactate dehydrogenase activities. Mean +/- s.d. ambient environmental temperature during the Endurance Test was 25.3 +/- 1 degrees C (range 20.3 degrees C-29.7 degrees C). Mean relative humidity was 43.8 +/- 2.4% (range 39%-48.6%) and the average 'comfort index' (CI) was 121. There were no significant differences between the groups competing in the Endurance Test, despite the shorter Phase B. However, there were significant decreases in BW, TBW, net exchangeable cations, chloride, ionised calcium, and pH. The sodium and total calcium concentrations remained at near pre-event values. The PCV, TPP, lactate, potassium, glucose, aspartate aminotransferase, and lactate dehydrogenase activity increased during the Endurance Test, when compared to pre-event values. Horses competing in this competition experienced significant fluid and electrolyte losses, reduced glomerular filtration, increased glycogenolysis and had significant leakage of enzymes from working muscles during competition. These changes could not be reduced by shortening Phase B and lengthening Phase C. 相似文献
16.
An associated solution model is applied to describe the thermodynamic behavior of Fe-S liquid. This model assumes the existence
of ‘FeS’ species in addition to Fe and S in the liquid. With two solution parameters for each of the binaries Fe-‘FeS’ and
‘FeS’-S, this model accounts for the compositional dependence of the thermodynamic properties of Fe-S liquid from pure Fe
to pure S over a wide range of temperature. The binary Fe-S does not contribute significantly to the excess Gibbs energy of
the liquid due to the rather small dissociation constant of ‘FeS’ to Fe and S. Using this model for the liquid phase and a
defect thermodynamic model for the pyrrhotite phase, the Fe-S phase diagram is calculated. The calculated diagram is in excellent
agreement with the experimental data, accounting for the range of homogeneity of pyrrhotite at all temperatures. Both the
thermodynamic and phase diagram data are obtained from the literature.
Formerly Post-Doctoral Research Associate, Materials Department, College of Engineering and Applied Science, University of
Wisconsin-Milwaukee. 相似文献
17.
Yu. I. Ustinovshikov 《Russian Metallurgy (Metally)》2009,(5):437-440
Experimental results that are obtained by electron microscopy, X-ray diffraction, and carbide analysis and indicate the precipitation
of carbon atoms clusters in a hypereutectoid steel during its annealing above the eutectoid temperature are presented. These
results are compared to the reported data in order to construct a new Fe-C phase diagram, where cementite forms below the
eutectoid temperature due to the tendency of the Fe-C system toward ordering and carbon unbound to iron precipitates above
this temperature in the form of clusters or graphite particles due to the tendency of this system toward phase separation. 相似文献
18.
Lars-Ingvar Staffansson 《Metallurgical and Materials Transactions B》1976,7(1):131-134
Using a DTA technique the melting point of pure MnS has been determined to 1655 ±5°C. The monotectic temperature in the Mn-MnS
system was found to be 1570 ±5°C. With these new data a thermodynamic analysis of the Mn-MnS system was carried out applying
a previously developed thermodynamic model. 相似文献
19.
X. Z. Li K. -T. Park K. Sugiyama K. Hiraga 《Metallurgical and Materials Transactions A》1998,29(6):1559-1563
An F-type icosahedral phase and a related cubic phase (composition of Al66.1Rh21.5Cu12.3, lattice constant a=1.5380(2) nm, and space group of Fm3) were observed in the Al63Rh18.5Cu18.5 alloy by transmission electron microscopy (TEM). The structure of the Al-Rh-Cu cubic phase was determined by single-crystal
X-ray analysis. A high-resolution electron microscopic image of the Al-Rh-Cu cubic phase is presented together with a simulated
image. The structure of the cubic phase can be described by two types of atom clusters, which have outer shells with icosahedral
symmetry. It is suggested that the structure of the Al-Rh-Cu cubic phase is helpful for understanding the structure of the
i-Al-Rh-Cu F-type icosahedral quasicrystal. 相似文献