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| tutorials:t2 [2019/07/18 15:48] – [T2: Calculating a single equilibrium] pwarczok | tutorials:t2 [2023/08/01 14:43] (current) – pwarczok |
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| //This tutorial was tested on \\ | //This tutorial was tested on \\ |
| MatCalc version 6.02 rel 1.003 \\ | MatCalc version 6.04 rel 1.001 \\ |
| license: free \\ | license: free \\ |
| database: mc_fe.tdb // | database: mc_fe.tdb // |
| Click {{:tutorials:t2:script:t2_6021003.mcs|here}} to view the script for this tutorial. | Click {{:tutorials:t2:script:t2_6021003.mcs|here}} to view the script for this tutorial. |
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| This tutorial explains how to determine the equilibrium phases at a given temperature, and their phase fractions and compositions. | This tutorial explains how to determine the equilibrium phases at a given temperature, their phase fractions and compositions. |
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| ==== Contents ==== | ==== Contents ==== |
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| ===== Setting up the system ===== | ===== Setting up the system ===== |
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| | The system setup is the very first operation that needs to be performned by MatCalc user. |
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| ==== Opening a thermodynamic database and selecting elements and phases ==== | ==== Opening a thermodynamic database and selecting elements and phases ==== |
| In the **'Global'** menu, select **'Databases'**. | In the **'Global'** menu, select **'Databases'**. |
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| {{:tutorials:t2:img:t2_global_database_6021003.png|Open databases window}} | {{:tutorials:t2:img:t2_global_database_6041000.png|Open databases window}} |
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| A window will appear as shown below. | A window will appear as shown below. |
| In the **'Global'** menu, select **'Composition'**. | In the **'Global'** menu, select **'Composition'**. |
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| {{:tutorials:t2:img:t2_global_composition_6021003.png| Open composition window}} | {{:tutorials:t2:img:t2_global_composition_6041000.png| Open composition window}} |
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| This opens the **'Nominal composition'** box. The lower part of the box gives options for the units in which the composition is to be displayed: mole fraction, weight fraction, u-fraction or weight percent. One of the elements, usually the one with the highest mole fraction, is designated as the **'reference element'**, and the amount of this element is calculated as **1-(sum of the amounts of all other elements)** for compositions expressed in fractional form, or **100-(sum of the amounts of all other elements)** for compositions expressed as percentages. \\ | This opens the **'Nominal composition'** box. The lower part of the box gives options for the units in which the composition is to be displayed: mole fraction, weight fraction, u-fraction or weight percent. One of the elements, usually the one with the highest mole fraction, is designated as the **'reference element'**, and the amount of this element is calculated as **1-(sum of the amounts of all other elements)** for compositions expressed in fractional form, or **100-(sum of the amounts of all other elements)** for compositions expressed as percentages. \\ |
| Iron is set as the reference element by default in the 'mc_fe.tdb' database, as can be seen from the **'Ref. Elem'** column in the composition dialogue box. Another element can be set as the reference by selecting the element name and clicking on the **'Set reference element'** button on the right, or by double-clicking in the **'Ref. Elem'** column by the side of the element name. \\ | Iron is set as the reference element by default in the 'mc_fe.tdb' database, as can be seen from the **'Ref. Elem'** column in the composition dialogue box. Another element can be set as the reference by selecting the element name and clicking on the **'Set reference element'** button on the right, or by double-clicking in the **'Ref. Elem'** column by the side of the element name. \\ |
| To enter a composition of **0.4 wt.% C**, select **'weight percent'** as the unit, then highlight element C. Double-click in the **'Amount'** column or click on the **'Change'** button to modify the composition, then type in **'0.4'** and press **'Enter'**. \\ | To enter a composition of **0.4 wt.% C**, put a checkmark in **'in percent'** box and select **'weight percent'** as the unit, then highlight element **'C'**. Double-click in the **'Amount'** column or click on the **'Change'** button to modify the composition, then type in **'0.4'** and press **'Enter'**. \\ |
| The system is now ready to perform an equilibrium calculation. | The system is now ready to perform an equilibrium calculation. |
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| {{:tutorials:t2:img:t2_system_composition_6021003.png| System composition setup}} | {{:tutorials:t2:img:t2_system_composition_6041000.png| System composition setup}} |
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| Click on **'OK'** to close this window | Click on **'OK'** to close this window |
| From the **'Calc'** menu, select **'Set start values'**. This initializes the calculation variables with reasonable values in order to help the Gibbs free energy minimizer to find a solution which satisfies all the boundary conditions. This command is useful if the solution algorithm seems to be 'stuck' and unable to find an equilibrium. | From the **'Calc'** menu, select **'Set start values'**. This initializes the calculation variables with reasonable values in order to help the Gibbs free energy minimizer to find a solution which satisfies all the boundary conditions. This command is useful if the solution algorithm seems to be 'stuck' and unable to find an equilibrium. |
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| {{:tutorials:t2:img:t2_set_start_values_6021003.png|Set start values}} | {{:tutorials:t2:img:t2_set_start_values_6041000.png|Set start values}} |
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| Once one valid equilibrium has been found, solutions at other temperatures or boundary conditions are much easier to obtain. From the **'Calc'** menu, select **'Equilibrium'**, or click on the {{:tutorials:t2:img:icon_equilibrium.png| MatCalc icon equilibrium}} icon in the toolbar. | Once one valid equilibrium has been found, solutions at other temperatures or boundary conditions are much easier to obtain. From the **'Calc'** menu, select **'Equilibrium'**, or click on the {{:tutorials:t2:img:icon_equilibrium.png| MatCalc icon equilibrium}} icon in the toolbar. |
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| {{:tutorials:t2:img:t2_equilibrium_6021003.png|Equilibrium settings}} | {{:tutorials:t2:img:t2_equilibrium_6041000.png|Equilibrium settings}} |
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| The following window appears: | The following window appears: |
| The **'Options'** window provides display options for the currently highlighted window. In the case of the **'Phase details'** window, the composition can be displayed as a mole fraction, a weight fraction or a u-fraction, and can also be expressed as a percentage if required. | The **'Options'** window provides display options for the currently highlighted window. In the case of the **'Phase details'** window, the composition can be displayed as a mole fraction, a weight fraction or a u-fraction, and can also be expressed as a percentage if required. |
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| {{:tutorials:t2:img:t2_options_window_6001000.png| MatCalc options window}} | {{:tutorials:t2:img:t2_options_window_6041000.png| MatCalc options window}} |
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| ==== Phase status: suspended and fixed phase fraction ==== | ==== Phase status: suspended and fixed phase fraction ==== |
| By default, the results from a previous equilibrium calculation are overwritten when a new calculation is carried out. However, it is sometimes useful to store the results from a calculation for future use. The **'Calculation states'** feature is provided for this purpose; it can be found in the **'Global'** menu under **'CalcStates'**. In the sub-menu, click on **'Create'** and type the name in the box: | By default, the results from a previous equilibrium calculation are overwritten when a new calculation is carried out. However, it is sometimes useful to store the results from a calculation for future use. The **'Calculation states'** feature is provided for this purpose; it can be found in the **'Global'** menu under **'CalcStates'**. In the sub-menu, click on **'Create'** and type the name in the box: |
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| {{:tutorials:t2:img:t2_create_calc_state_6021003.png|Create calculation state}} | {{:tutorials:t2:img:t2_create_calc_state_6041000.png|Create calculation state}} |
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| {{:tutorials:t2:img:t2_calc_state_name_6021003.png|Calcuation state name}} | {{:tutorials:t2:img:t2_calc_state_name_6021003.png|Calcuation state name}} |
| The calculation state stores all information on an equilibrium including the complete phase status, composition and any compositional states which may apply. Calculate another equilibrium at 600°C and store it by creating another calculation state. These states are now both available in the calculation state drop-box on the toolbar: | The calculation state stores all information on an equilibrium including the complete phase status, composition and any compositional states which may apply. Calculate another equilibrium at 600°C and store it by creating another calculation state. These states are now both available in the calculation state drop-box on the toolbar: |
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| {{:tutorials:t2:img:t2_load_calc_state_6021003.png?650|Calculation states list}} | {{:tutorials:t2:img:t2_load_calc_state_6041000.png?650|Calculation states list}} |
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| Select a calculation state from this box and load the stored equilibrium with the {{:tutorials:t2:img:load.png?30| MatCalc load}} button. This can also be done using **'Global > CalcStates > Select'** and then **'Load'**. Note how the contents of the **'Phase details'** and **'Phase summary'** windows are immediately updated with the results stored in the calculation state, and the temperature at which the equilibrium was calculated is shown in the status bar towards the bottom right of the screen. The results of the current equilibrium calculation can be saved into an existing calculation state by selecting the name of the state in the drop-box and then clicking on the {{:tutorials:t2:img:icon_save.png?30| MatCalc save}} button or using **'Global > CalcStates > Select'** and then **'Save'**. **NB: Calculation states, like all other calculation results, are erased when data is re-read from the database!** | Select a calculation state from this box and load the stored equilibrium with the {{:tutorials:t2:img:load.png?30| MatCalc load}} button. This can also be done using **'Global > CalcStates > Select'** and then **'Load'**. Note how the contents of the **'Phase details'** and **'Phase summary'** windows are immediately updated with the results stored in the calculation state, and the temperature at which the equilibrium was calculated is shown in the status bar towards the bottom right of the screen. The results of the current equilibrium calculation can be saved into an existing calculation state by selecting the name of the state in the drop-box and then clicking on the {{:tutorials:t2:img:icon_save.png?30| MatCalc save}} button or using **'Global > CalcStates > Select'** and then **'Save'**. **NB: Calculation states, like all other calculation results, are erased when data is re-read from the database!** |
