Modules
UTILITY
The MTDATA package includes a number of utilities for creating, loading and listing databases. Facilities are also incorporated for personalising access to particular databases and for customising graphics output as exemplified in some of the graphs below. The box shows as an example part of a source datafile to be incorporated into a database by UTILITY.
Cr/+3,Ni/+2:Va<LIQUID*> E/J
*** GEX(REDLICHKISTER) DATASET FORMAT ***
298.150 2
2
1.2760000E+03 5.3873000E+00
2
2.6990000E+03 0.0000000E+00
3000.00
0 0
ACCESS
The ACCESS module is designed to be used as a data retrieval system for MULTIPHASE, GPLOT, BINARY, TERNARY, APPLICATION and COPLOT, with which it shares common features. The components, which may be elements, compounds or charged species, are entered and the databases are searched for all the substances which might be present in the system at equilibrium. In a large system this could run to many hundreds of substances, many of which may not be very relevant to a particular application and may therefore be excluded. ACCESS allows the user to remove these substances from consideration completely, and to choose from which databases the data for the remaining substances are to be retrieved on an individual basis. There may also be a need to select from alternative models for solution phases. Once the data for the system have been edited into a form which satisfies the user, they can be saved to a file which can then be read by the calculation modules for subsequent processing.
ACCESS OPTION ? define system 'Fe,Cr,Ni,C' source sgsol !
SEARCHING FOR SYSTEM Fe,Cr,Ni,C
SEARCHING DATABASE(S) : SGSOL SGTE Solution Database 3.0 2/2/93
ACCESS OPTION ? list sys phases ! The list has been greatly abbreviated
NUMBER PHASE STATUS MODEL
3 LIQUID NORMAL REDLICHKISTER
4 GAS NORMAL IDEAL GAS
5 BCC_A2:1:3 NORMAL SUBLATTICE
6 CEMENTITE:3:1 NORMAL SUBLATTICE
7 FCC_A1:1:1 NORMAL SUBLATTICE
8 HCP_A3:1:.5 NORMAL SUBLATTICE
10 M3C2:3:2 NORMAL SUBLATTICE
11 M7C3:7:3 NORMAL SUBLATTICE
12 M23C6:20:3:6 NORMAL SUBLATTICE
22 SIGMA:8:4:18 NORMAL SUBLATTICE
MULTIPHASE
MULTIPHASE is a module for the calculation of multiphase, multicomponent equilibria. Phases may include alloys, molten salts, gases, aqueous solutions, slags, mattes and pure stoichiometric substances in combination. Calculations may be made at constant pressure or volume with a fixed system composition; alternatively, constraints may be placed on the equilibrium system in terms of variables such as mole fraction in a phase, partial pressure and molality. Data for the calculations are read either from specified databases, or from a previously prepared datafile; this may be precompiled by using the ACCESS module.
Output, in the form of tabulated equilibrium amounts and mole fractions of each of the substances present at equilibrium, for each of the temperatures specified, is sent both to the terminal and to a file. Graphical output can be invoked from within MULTIPHASE in order to plot the amounts, mole fractions, partial pressures, component partition between phases and activities as a function of stepped or dependent variables. Results may be presented in mole or weight terms.
THERMOTAB
The main function of THERMOTAB is to act as the user interface to the internal database management system of MTDATA. At present all data can be inspected but calculations involving equations are available only for pure substances, gases and dilute aqueous species.
The UTILITY module should be used for data management for solution phases. UNARY, GPLOT and MULTIPHASE can be used to obtain tabulations and plots.
Fe3O4 + 3 H/+<aq> = 1/2 O2<g> + 3 Fe(OH)/+<aq>
T Delta Cp Delta H Delta S Delta G Beta
K J/K mol J/mol J/K mol J/mol DG/RTln10
298.15 13.277 1.48680E+05 133.27 1.88413E+05 33.008
373.15 10.914 1.49606E+05 130.49 1.98297E+05 27.758
473.15 0.21007 1.50253E+05 128.90 2.11243E+05 23.320
573.15 22.630 1.49241E+05 130.77 2.24193E+05 20.432
THERMOTAB provides output of the Thermodynamic functions Cp, S, G, H, Phi = (GH)/T and Beta = G/RTln10, over a range of temperatures specified by the user, for pure substances or for chemical reactions between pure substances. The output can be produced in tabular or graphical form, and may be displayed on the screen or saved to a file. Hard copy can be obtained by routing the file to a local or networked printer or plotter. The module also allows data to be copied from the reference databases provided, modified by the user, and used to compile private or specialised databases.
UNARY
UNARY is used in data development, for example the provision of data for a liquid below the melting temperature of the pure substance. It is also useful in the graphical comparison of data from different sources or different phases.
GPLOT
GPLOT is used mainly for plotting but also for tabulating thermodynamic functions of phases of all types. The main application lies in the development of data for binary systems which can include systems between compounds.
0.0 0.2 0.4 0.6 0.8 1.0 800 1000 1200 1400 1600 1800 2000 AlTi x Ti Temperature / K Al Ti BCC_A 2 LIQUID TIAL TI 3 AL AL 3 TI AL 1 1TI 5 AL 2 1TI HCP_A 3
BINARY
The BINARY module is used for the calculation and plotting of binary phase diagrams, mainly as an aid to data assessment and validation. The data are retrieved in the same way as with the ACCESS module. The user sets up the calculation by specifying the temperature range and he may subsequently select parts of the diagram for closer inspection.
Labelling of single or two phase regions is very simple. Key information on phase boundaries is given numerically and hard copy can readily be obtained.
TERNARY
FeCrNi 1023 K 1.01325E5 Pa Fe Cr Ni 0.8 0.6 0.4 0.2 0.8 0.6 0.4 0.2 0.2 0.4 0.6 0.8 Cr x Ni Fe Plotted 14:51:48 11JAN94 Data file FeCrNi.MPI Results file FeCrNi54.TNR Log file C:MTDATAMTWORKMT442.LOG SIGMA FCC_A 1 BCC_A 2 BCC_A
The TERNARY module is used to plot ternary phase diagrams. Data may be retrieved directly databases or from a datafile compiled using the ACCESS module. The user may optionally specify a starting point on the ternary diagram for the calculations to begin; thereafter the computations required for the graph to be plotted can be entirely automatic. The diagram can be in weight or mole % and miscibility gaps can be calculated. Areas can readily be labelled and diagrams reorientated. The resulting plot is shown on the terminal
0.0 0.2 0.4 0.6 0.8 1.0 0.0 0.2 0.4 0.6 0.8 1.0 NaCl KCl KI NaI NaClNaIKClKI 850 K 1.01325E5 Pa Plotted 12:21:14 10JAN94 Data file DEF.MPI Results file DEF22.TNR Log file C:MTDATASALTSMT8.LOG and written to a file. Hard copy of the plot can be obtained by routing the contents of the file to a local plotter. The graphical interactive user interface is compatible with many types of equipment. Two diagrams produced by TERNARY are illustrated: a standard ternary diagram for the FeCrNi system and a reciprocal plot for the NaClNaIKClKI system. 1.9 APPLICATION 0.0 0.2 0.4 0.6 0.8 1.0 35 30 25 20 15 10 fno118 14:02:36 23JUL93 mol fraction Cr of (Cr + Fe) log 10 pO2 / atm COR SPL + COR HAL + SPL SPL SPL SPL + SPL BCC + SPL BCC + SIG BCC + SIG BCC BCC BCC + COR HAL
APPLICATION
APPLICATION allows MULTIPHASE to be used for a variety of purposes as illustrated below: including making arbitrary sections through systems, finding the temperatures of phase transitions for individual compositions and the preparation of Scheil plots. The facility is provided for users to develop their own process modelling software for linking to MTDATA.
The Ca 2 SiO 4 Mg 2 SiO 4 system is not a true
binary. The diagram takes account of the fact
that the composition of the liquid and halite
phases do not lie along the binary join.
0 10 20 30 40 50
500
1000
1500
2000
2500
fe_p.mpi 10JAN94 14:19:11
Pressure GPa
Temperature
/
K
Triple points
found
1: .5141E+10 Pa
1979.7 K
2: .1046E+11 Pa
756.6 K
Data fe_p.mpi
Log mt2327.log
Plotted 14:19:11 10JAN94
LIQUID
FCC_A 1
HCP_A 3
BCC_A 2
BCC_A
An application is also used to calculate
and plot temperaturepressure
diagrams, in this case for pure iron.
Multicomponent diagrams may also be
produced.
GENERAL INTRODUCTION JANUARY 1994
MTDATA HANDBOOK page 7
30 25 20 15 10 5 0
20
15
10
5
0
UOF 1800 K
log p O2
FITANDPLOT
FITANDPLOT is used for fitting compiled thermodynamic data to user defined mathematical functions. It incorporates checking for typing errors and can also be used for converting data already in the form of an equation to a different function.