SIMULATION, DESIGN, AND EXPERIMENT OF HIGH-ENTROPY ALLOYS ALXTI0.3CR0.7FE0.8CONIY WITH ADDITION OF SI-NB USING SPARK PLASMA SINTERING

• Main Author: Sahid, Ahmad
• Format: Theses
• Language: Indonesia
• Online Access: https://digilib.itb.ac.id/gdl/view/57962
• Institution: Institut Teknologi Bandung

High-entropy alloys are alloys with a composition of more than five major elements and some minor elements. High-entropy alloys with high mechanical properties are promising candidate for structural applications at high temperatures. Efforts to design high-entropy alloys were carried out using various approaches, including using thermodynamic and physical parameters. This approach can predict phase formation with its crystal structure. One of the commonly used high-entropy alloy fabrication is through the arc melting process. However, other alternative processes such as spark plasma sintering have not been widely used. This study aimed to design high-entropy alloys through simulation of thermodynamic and physical parameter calculations and then verified through the spark plasma sintering process. The alloys were characterized using SEM, EDS, and XRD, then mechanical testing was carried out using compression test and Vickers hardness test. Simulation and design resulted high-entropy alloy AlxTi0.3Cr0.7Fe0.8CoNiy (x = 0.7 and y = 2.5 designated as A1; x = 1.0 and y = 2.0 designated as A3). The addition of Si-Nb to A1 and A3 formed A2 and A4 respectively. XRD data showed the formation of FCC and BCC solid solutions and FCC intermetallic. Without the addition of Si-Nb, the microstructure of the alloy showed traces of suppression flow with a lamellar structure in the matrix and particles. While the alloy with the addition of Si-Nb microstructure was more homogeneous with globular particles. The reduction of Ni and addition of Al composition such as from A1 to A3, as well as the addition of Si-Nb contributed to the increase in hardness and compressive strength values. Particularly for A4 produces a hardness and compressive strength of 696 HV and 2350 MPa, respectively, which is superior to the most high-strength alloys.