Integral Variables

An integral variable is a quantity that has been obtained by integration in space over the whole system or over a specific region. In a planar geometry values are given per unit area, in a cylindrical geometry they are given per unit length, and in a spherical geometry they are absolute values.

SET_DIAGRAM_AXIS and ENTER_SYMBOL commands in the DICTRA POST module.

The variable mnemonics are constructed in the following way.

  • The first letter is always I for INTEGRAL VARIABLE.
  • The second letter specifies quantity.
  • The third letter is OPTIONAL and specifies the normalizing quantity.
Class Quantity Description

I

N

for number of moles

I

W

for mass

I

V

for volume

I

U

for number of moles of volume-contributing elements

II

S

for entropy

II

H

for enthalpy

II

G

for Gibbs energy

II

A

for Helmholtz energy

Integral quantities of CLASS=I may take 0-3 arguments.

The arguments MUST be given in 'falling' order of significance.

  1. Region name
  2. Phase name
  3. Component name

Integral quantities of CLASS=II may take 0-2 arguments.

The arguments MUST be given in 'falling' order of significance.

  1. Region name
  2. Phase name
Quantity Description

N

for total number of moles in system

W

for total mass of system

V

for total volume of system

U

for total number of moles of volume-contributing elements in system
Variable Definition

IW(PEARLITE,BCC,CR)

The mass of CR in the BCC phase in region PEARLITE.

IW(PEARLITE,BCC)

The mass of BCC phase in region PEARLITE. IW is the total mass in the system.

IVV(Austenite)

The volume fraction of Austenite in a single cell calculation.

IVV(2, Austenite)

The volume fraction of Austenite in Cell 2 for a multi cell calculation.