# GrandPotentialInterface

Calculate Grand Potential interface parameters for a specified interfacial free energy and width

The multiphase Grand Potential model is parameterized using a bulk free energy coefficient , a gradient interface coefficient , and a set of interface pair coefficients Aagesen et al. (2018). Note that this model is a multi phase / poly crystal model and the indices and represent phases and and represent grains.

This material class provides the above mentioned parameters and calculates them using the physical parameters of the free energy area density (sigma) for the interface between each pair of phases, and an interface width (width).

To compute the parameters first either the median of all is chosen or, if supplied by the user, the entry with the index sigma_index is chosen (overriding the median computation). The chosen is assigned a value . For this gamma value a set of analytical expessions holds

(1)

note:Interface widths

Note that the interface with (width) is only guaranteed for the interface with either the median or - if provided - the index supplied in sigma_index. All other interface widths are a function of their respective interfacial free energies.

With and determined the remaining can be computed using the fitted relation Moelans (2009)

(2)

The material propertied provided by this class are directly used by the ACGrGrMulti and ACInterface objects and indirectly used by the GrandPotentialKernelAction.

## Input Parameters

• widthInterfacial width (for the interface with gamma = 1.5)

C++ Type:double

Options:

Description:Interfacial width (for the interface with gamma = 1.5)

• sigmaInterfacial free energies

C++ Type:std::vector

Options:

Description:Interfacial free energies

### Required Parameters

• gamma_namesInterfacial / grain boundary gamma parameter names (leave empty for gamma0... gammaN)

C++ Type:std::vector

Options:

Description:Interfacial / grain boundary gamma parameter names (leave empty for gamma0... gammaN)

• boundaryThe list of boundary IDs from the mesh where this boundary condition applies

C++ Type:std::vector

Options:

Description:The list of boundary IDs from the mesh where this boundary condition applies

• computeTrueWhen false, MOOSE will not call compute methods on this material. The user must call computeProperties() after retrieving the Material via MaterialPropertyInterface::getMaterial(). Non-computed Materials are not sorted for dependencies.

Default:True

C++ Type:bool

Options:

Description:When false, MOOSE will not call compute methods on this material. The user must call computeProperties() after retrieving the Material via MaterialPropertyInterface::getMaterial(). Non-computed Materials are not sorted for dependencies.

• blockThe list of block ids (SubdomainID) that this object will be applied

C++ Type:std::vector

Options:

Description:The list of block ids (SubdomainID) that this object will be applied

Default:kappa

C++ Type:MaterialPropertyName

Options:

### Optional Parameters

• output_propertiesList of material properties, from this material, to output (outputs must also be defined to an output type)

C++ Type:std::vector

Options:

Description:List of material properties, from this material, to output (outputs must also be defined to an output type)

• outputsnone Vector of output names were you would like to restrict the output of variables(s) associated with this object

Default:none

C++ Type:std::vector

Options:

Description:Vector of output names were you would like to restrict the output of variables(s) associated with this object

### Outputs Parameters

• enableTrueSet the enabled status of the MooseObject.

Default:True

C++ Type:bool

Options:

Description:Set the enabled status of the MooseObject.

• mu_namemuGrain growth bulk energy parameter name

Default:mu

C++ Type:MaterialPropertyName

Options:

Description:Grain growth bulk energy parameter name

• use_displaced_meshFalseWhether or not this object should use the displaced mesh for computation. Note that in the case this is true but no displacements are provided in the Mesh block the undisplaced mesh will still be used.

Default:False

C++ Type:bool

Options:

Description:Whether or not this object should use the displaced mesh for computation. Note that in the case this is true but no displacements are provided in the Mesh block the undisplaced mesh will still be used.

• control_tagsAdds user-defined labels for accessing object parameters via control logic.

C++ Type:std::vector

Options:

Description:Adds user-defined labels for accessing object parameters via control logic.

• seed0The seed for the master random number generator

Default:0

C++ Type:unsigned int

Options:

Description:The seed for the master random number generator

• sigma_indexSigma index to choose gamma = 1.5 for. Omit this to automatically chose the median sigma.

C++ Type:unsigned int

Options:

Description:Sigma index to choose gamma = 1.5 for. Omit this to automatically chose the median sigma.

• implicitTrueDetermines whether this object is calculated using an implicit or explicit form

Default:True

C++ Type:bool

Options:

Description:Determines whether this object is calculated using an implicit or explicit form

• constant_onNONEWhen ELEMENT, MOOSE will only call computeQpProperties() for the 0th quadrature point, and then copy that value to the other qps.When SUBDOMAIN, MOOSE will only call computeSubdomainProperties() for the 0th quadrature point, and then copy that value to the other qps. Evaluations on element qps will be skipped

Default:NONE

C++ Type:MooseEnum

Options:NONE ELEMENT SUBDOMAIN

Description:When ELEMENT, MOOSE will only call computeQpProperties() for the 0th quadrature point, and then copy that value to the other qps.When SUBDOMAIN, MOOSE will only call computeSubdomainProperties() for the 0th quadrature point, and then copy that value to the other qps. Evaluations on element qps will be skipped