Oxidation and Corrosion properties of a Novel Al₁₅Ti₃₀Si₃₀Mo₁₅Ni₁₀ High Entropy Alloy fabricated by Spark Plasma Sintering Technology

Abstract

The need for new advanced high temperature materials is in high demand. High Entropy Alloy (HEAs) has been described to possess excellent mechanical oxidation and good corrosion resistance properties even far above the ambient temperature. Attempts are made in this research to study the corrosion, oxidation, microhardness and densification properties of Al15Ti30Si30Mo15Ni10 HEA produced by spark plasma sintering (SPS) for high temperature applications. In addition, the effects of SPS temperature (800, 900 and 1000°C) on the microstructure and phase formation of the developed HEA were reported. The microstructural modification and phases present were examined using the scanning electron microscope (SEM) equipped with the energy dispersive spectroscopy (EDS) and X-ray diffractometer (XRD) respectively. Ordered FCC and BCC systems were identified along with clearly defined crystal lattice along with Mo, Ti and Si rich regions were observed. No pores or cracks were observed from the microstructures. Densification of 98.8% accompanied with microhardness of 1445.29HV was achieved for both HEA at 1000°C. The Al15Ti30Si30Mo15Ni10 HEA fabricated at 1000°C displayed a higher polarization value of 3477 Ω.

Mechanical and thermal behaviors of Ti36-Al16-V16-Fe16-Cr16 high entropy alloys fabricated by spark plasma sintering: An advanced material for high temperature/strength applications

“…The resistance to oxidation of sample sintered at 1000°C is attributed to the fact that it possessed the most refined grains in the microstructure devoid of pores and impurities which helped in the formation of thick protective layer that resisted oxidation just as was reported in another study. 25…”

“…It was conducted at a heating rate of 20°C/min and temperature range of 25 – 1000°C for 120 min in air atmosphere as employed and reported in Ref. 25.…”