SIMULATION OF THE EFFECT OF MN ADDITION ON HIGH ENTROPY ALLOY ON ELASTICITY PROPERTIES: A FIRSTPRINCIPLES STUDY

• Main Author: Nugraha Nurhadiansyah, Dicky
• Format: Final Project
• Language: Indonesia
• Online Access: https://digilib.itb.ac.id/gdl/view/85009
• Institution: Institut Teknologi Bandung

The development of human civilization increasingly drives the need for materials with high performance in certain conditions, especially the use of materials for high temperatures such as power plants which are useful for energy availability and have become one of the strategies in supporting strategic industrial development. An alloy that has the potential for this application is FeNiCoCr. However, a high concentration of cobalt (Co) can increase the cost of raw materials for the alloy, so adding other alloying elements such as manganese (Mn) which is cheaper can be an alternative solution to this problem. Therefore, this research discusses the effect of Mn addition on lattice parameters, mechanical properties especially related to elasticity, stacking fault energy (SFE), and electronic structure including density of states (DOS) and charge density difference. The simulation and calculation were carried out using Cambridge Sequential Total Energy Package (CASTEP) using First-Principles Density Functional Theory. The lattice parameter, SFE, and electronic structure simulations were carried out on 24 atoms with the addition of Mn 4.17 at.% and 8.33 at.%, while the elastic constant simulations were carried out on 16 atoms with the addition of Mn 6.25 at.% and 12.5 at.%. Calculation of mechanical properties related to elasticity using Voigt- Reuss-Hill approximation and Tian equation model. Voigt-Reuss-Hill approximation is used to obtain strength and ductility, while Tian equation model is used to determine hardness. The addition of Mn 4.17 at.% and 8.33 at.% will increase the lattice parameters from 3.51 Å to 3.514 Å and 3.517 Å. When the lattice parameters increase, it will increase the strength and hardness. The addition of Mn increased the SFE value respectively from 74.37 mJ/m2 to 156.69 mJ/m2 and 141.98 mJ/m2. Correspondingly, the DOS value increases at the Fermi level and the charge accumulation region decreases, indicating an increase in the bond strength between atoms. The addition of Mn 6.25 at.% and 12.5 at.% also increases the elastic modulus and hardness but reduces ductility even though the addition of Mn 6.25 at.% is still categorized as a ductile alloy.