EFFECTS OF VARIATIONS IN CONCENTRATION OF FENICRCOCU HIGH ENTROPY SUPERALLOY ELEMENTS ON ITS MECHANICAL PROPERTIES USING MOLECULAR DYNAMIC SIMULATION

• Main Author: Geanari Vollindia, Attala
• Format: Final Project
• Language: Indonesia
• Online Access: https://digilib.itb.ac.id/gdl/view/80513
• Institution: Institut Teknologi Bandung

FeNiCrCoCu alloy is a Fe-based high entropy superalloy that has radiation, creep, creep-fatigue, and corrosion resistance as well as high strength and ductility. This alloy is one of the candidates that can be used in the manufacture of nuclear reactors because of its resistance to extreme conditions such as temperature, corrosion levels, stress, and high heat flux. The FeNiCrCoCu alloy was chosen because it has good phase stability and only undergoes minor structural changes when irradiated compared to other Ni alloys. Studying metal alloys through experiments requires a lot of time, energy, and cost, so computational methods are needed to simulate the effect of alloy composition on mechanical properties. Design simulation of FeNiCrCoCu alloy using molecular dynamics (MD) method has been conducted to study the effect of alloy composition on lattice parameter, ultimate compression strength (UCS), stacking fault energy (SFE), and elastic modulus, as well as the effect of lattice parameter on UCS, SFE, and elastic modulus. MD simulations were performed using the LAMMPS package with FCC alloy structure and composition variations of Cu, Cr, Co, Ni at 11.75 at%-16.25 at% and Fe at 35 at%-39.5 at%. The simulation was carried out with a random atomic distribution at a temperature of 300 K. The simulation begins with elemental optimization to obtain parameter kisi values, followed by UCS and SFE calculations. From the simulation results, the lattice parameter of high entropy superalloy (HESA) Fe35(NiCrCoCu)16.25 is 3.554 Å, high entropy alloy (HEA) FeNiCrCoCu is 3.552 Å, and the medium entropy alloy (MEA) FeNiCrCo is 3.549 Å. Increasing the concentrations of Ni, Cr, and Co will decrease the lattice parameter, while increasing the concentration of Cu will increase the lattice parameter. The UCS HESA value of Fe35(NiCrCoCu)16.25 is 8.863 GPa and the UCS HEA of FeNiCrCoCu is 8.916 GPa. Increasing the concentration of Cu, Cr, and Co elements will decrease the UCS while increasing the concentration of Ni will increase the UCS. The SFE value of MEA FeNiCrCo was 74.659 mJ/m², HEA FeNiCrCoCu was 64.963 mJ/m², and HESA Fe35(NiCrCoCu)16.25 was 60.708 mJ/m². Increasing the concentration of Ni and Cu will increase the SFE while Cr and Co will decrease the SFE value. So, by decreasing the SFE value will increase the lattice parameter, elastic modulus, and its strength but will decrease the ductility.