MedeAMT
   
Predicting Mechanical and Thermal Properties of Materials

Method and Scope

The MedeA-MT module provides a fully automated computational procedure for predicting mechanical and thermomechanical properties of materials such as high performance alloys, hard materials, oxides and other more complex materials. Exploiting MedeA's powerful paradigm of combining experimental structure data with predictive computational methods, MedeA-MT let's you determine valuable properties such as elastic coefficients, Young’s moduli, shear moduli, and thermal expansion coefficients with unprecedented reliability and ease.

Features

MedeA-MT calculates the following properties:

  1. Elastic constants
  2. Compliance matrix
  3. Bulk and shear moduli for a polycrystalline sample (*)
  4. Longitudinal and transverse velocities of sound (*)
  5. Debye temperature (*)
  6. Heat capacity and free energy (lattice contribution in Debye approximation)
  7. Thermal expansion coefficient (estimate within the Debye-Grüneisen approximation)

 

 

 

 

 
MedeA-MT is fully integrated with the first principle method VASP. Compute intensive applications in MT are supported through MedeA's parallel/serial job control and spreadsheet job submission. While the integrated analysis tools allow for simple visualization of results, easy data export to other Windows application is one of MedeA's generic features.

Application examples

Starting from a structural model retrieved from MedeA-InfoMaticA or imported/built by the user, MT let's you predict the elastic properties through a fully automated procedure, performing the following steps:

  • Determine the symmetry of the model
  • Find the pertinent set of independent elastic constants
  • Set up strains needed to compute stiffness matrix
  • Run computations for strained and unstrained geometries
  • Derive stiffness matrix from stress field using an efficient algorithm [1]
  • Calculate further thermomechanical data from output

Example 1 - Quartz

Quartz is one of the most common minerals in the earth’s crust. It has a wide range of technological applications, amongst them piezoelectrics and semiconductor devices. MedeA-MT determines the elastic properties of SiO2 in good agreement with experiments

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Example 2 - Tourmaline

For complex structures such as the below tourmaline (Schorl) the elastic constants can be readily determined using MedeA-MT. The unit cell contains 8 species and 159 atoms. Using a parallel compute cluster with 4 nodes (INTEL P-IV 2GHz or AMD 1800GHz) such a calculation can be run overnight (~ 50 hours on a single CPU).

 

Download MedeA-MT datasheet (.pdf)

Remarks

(*) The theory of Voigt, Reuß and Hill is employed to derive these properties.

References

  1. Y. Le Page and P. Saxe, Phys. Rev. B 65, 104104 (2002), Y. Le Page, P. Saxe and J. R. Rodgers, Phys. stat. sol. (b) 229, 1155 (2002) and unpublished
  2. Landolt-Börnstein, Vol. 29, Eds. A. G. Every and A. K. McCurdy, Springer-Verlag, Berlin/Heidelberg/New York 1992
  3. B. G. Helme and P. J. King, J. Mater. Sci. 13, 1487 (1978)

 
 
 

 

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