[MatSQ Tip] Module Utilization Tip: Stacking Fault Energy (Calphad) - Materials Square

## [MatSQ Tip] Module Utilization Tip: Stacking Fault Energy (Calphad)

2020-10-14 11:05:46

In the structural materials, the properties of the materials depend on the atomic configuration of crystal structures.

In particular, when dislocation occurs in the fcc structure during plastic deformation, the stacking fault is formed.

Since it is hard for the formation of stacking fault to perform the cross-slip, this situation affects the strength and ductility of the material.

Therefore, evaluating the formation energy of stacking fault is the significant factor to estimate the plasticity of the structural materials directly and indirectly.

Experimentally, the stacking fault energy can be directly estimated by TEM observations. However, due to the experimental error,  simulation methods can be used as an alternative for a more clear evaluation.

We already introduced about how to obtain the stacking fault energy using the ab-initio calculation.
(ref: #11 Energy Generated When Crystal Regularity Is Broken: Stacking Fault Energy)

But the first-principle calculation can't apply for the stacking fault energy of an alloy, which generally consisted of many elements.

To overcome this obstacle, MatSQ releases a 'Stacking fault energy' template which developed by using the empirical models[1,2] which developed by former researchers and thermodynamic calculation techniques.

'Stacking fault energy' template is for calculating the stacking fault energy in austenite steel and Ni-base alloys.

In this module tip, we'll learn about how to obtain the stacking fault energy of the alloy using the stacking fault energy template with example video.

The Procedure for using the Stacking fault energy Template

Step 1. Select the elements of the system.

Step 2. Select the database which describes the system.

Step 3. Set the initial conditions to obtain the stacking fault energy for each temperature.

At the ‘Element,’ determine the ratio of the Major element and other elements.
At the ‘Properties,’ enter the last heat treatment temperature and select the Mol or Weight.
Next, you should determine the temperature range (TBegin, TFinal).

After finishing the setting, set the 'Job name' and click the 'Start Job!' button to start the calculation.

You can obtain the following data.

By using the 'Stacking Fault Energy' template of the MatSQ Calphad module, you can easily calculate the stacking fault energy of an alloy that is difficult to calculate with the first-principle calculation.

Example video

>Webinar
MatSQ 103: Calphad with Materials Square
>Documentation

[1] Olson, G. B. & Cohen, M. A general mechanism of martensitic nucleation: Part I. General concepts and the FCC→HCP transformation. Metall. Trans. A 7, 1897–1904 (1976).
[2] [1] Y.-K. Kim, D. Kim, H.-K. Kim, C.-S. Oh, B.-J. Lee, An intermediate temperature creep model for Ni-based superalloys, Int. J. Plast. 79 (2016) 153–175.

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