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+ | ====== General considerations ====== | ||
+ | |||
+ | ===== Compatibility ===== | ||
+ | |||
+ | MatCalc version: 5.0 - ... \\ | ||
+ | Author: E. Kozeschnik \\ | ||
+ | Created: 2011-07-05 \\ | ||
+ | Revisions: | ||
+ | |||
+ | ===== Objectives ===== | ||
+ | |||
+ | In this document, general considerations for // | ||
+ | |||
+ | |||
+ | ===== Related documents ===== | ||
+ | |||
+ | none | ||
+ | ====== Main document ======= | ||
+ | |||
+ | |||
+ | ===== Before you start ... ===== | ||
+ | |||
+ | Before actually going into the software to perform the simulation, do **make sure you clearly know, which problem you want to solve, and how you want to realize your task**. For precipitation simulations, | ||
+ | |||
+ | Setup your precipitation simulation as simple as possible in order to avoid unnecessary computational effort. This //is// an issue in kinetic simulations. Once you have successfully completed simulations in a simplified system, gradually increase the complexity until you arrive at the answer to the problem you are seeking. If you are new to MatCalc precipitation simulations, | ||
+ | |||
+ | <box 90% round blue | //**And most important ...**//> | ||
+ | //MatCalc// is a simulation tool that follows a // | ||
+ | |||
+ | **//DO NOT use MatCalc as a fitting tool where you adjust the interfacial energy until the calculation fits your experiment!!!// | ||
+ | </ | ||
+ | |||
+ | |||
+ | The vision of //MatCalc// is to provide a // | ||
+ | |||
+ | In the 'How to' manual section on alloy specific issues, you can find tips and tricks that are relevant for the particular system. This will certainly assist you in identifying the important processes that you have to account for. If you still have trouble, see whether you can find an appropriate [[examples: | ||
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+ | ====== The representative volume element (RVE) ====== | ||
+ | |||
+ | When designing and performing precipitation kinetics simulations, | ||
+ | |||
+ | //MatCalc// **precipitation kinetics simulations** are carried out within a **// | ||
+ | |||
+ | * a single, homogeneous matrix (precipitation domain) containing all existing precipitates. This is a consequence of the // | ||
+ | * all precipitates are assigned to one single precipitation domain only at one time. It is possible to swap precipitates from one precipitation domain into another, though, to mimic phase transformations of the matrix phase. | ||
+ | * temperature, | ||
+ | |||
+ | The following graphics shows a sketch of the RVE for precipitation kinetics simulations. | ||
+ | |||
+ | {{ : | ||
+ | |||
+ | The RVE in //MatCalc// contains unit volume of matter, with an arbitrary number of different atomic species. The atoms can form precipitates of different type and different chemical composition. The precipitates are considered to be spherical objects, | ||
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+ | |||
+ | ====== Setting up a precipitation simulation ====== | ||
+ | |||
+ | When setting up a precipitation kinetics simulation, you commonly proceed with the following steps: | ||
+ | |||
+ | ===== Setup the thermodynamic system ===== | ||
+ | |||
+ | Create a new workspace. Then | ||
+ | |||
+ | * Open the desired database and //select elements and phases// that you want to work with. Read thermodynamic and mobility databases. | ||
+ | * Define nominal chemical composition. | ||
+ | |||
+ | ===== Create precipitation domain(s) ===== | ||
+ | |||
+ | If you want to simulation precipitation, | ||
+ | |||
+ | * **Create precipitation domain**. Use ' | ||
+ | * Select the **thermodynamic matrix phase**. This is the phase, which defines the thermodynamic properties of the precipitation domain. | ||
+ | * Enter the microstructure information in the ' | ||
+ | * **Grain size** (important for grain boundary precipitates) | ||
+ | * **Dislocation density** (important for dislocation precipitates as well as pipe diffusion) | ||
+ | * **Subgrain size** (important for subgrain boundary precipitates, | ||
+ | * For dislocation density above the equilibrium values ($10^{11}-10^{12}$), | ||
+ | * For grain boundary precipitates, | ||
+ | |||
+ | ===== Create precipitates ===== | ||
+ | |||
+ | For each desired precipitate, | ||
+ | |||
+ | * Define the desired **number of size classes** to use in the simulations. This quantity determines, which maximum number of size classes //MatCalc// will maintain during the simulations. Practically, | ||
+ | * Attach the precipitate to a **precipitation domain**. | ||
+ | * Do //not// change the automatic setting for the interfacial energy. The estimates delivered by //MatCalc// have shown to be quite reasonable in the majority of cases, and no significant changes are usually necessary at this stage. | ||
+ | * On the ' | ||
+ | |||
+ | ===== Optional settings ===== | ||
+ | |||
+ | Heat treatments ... | ||
+ | |||
+ | FIXME | ||
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+ | |||
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