Microstructure and anti-corrosion properties of near equi-atomic Ti25Si25Al20Mo20Ni10 High Entropy Alloy synthesized via Spark Plasma Sintering

Abstract

Materials operating at extreme conditions where they are exposed to corrosive environment can be realised in everyday applications. Suffer from corrosion due to acidic environment is still a challenge. Efforts have been made in material design to produce a suitable chemical plants material which can resist corrosion. High Entropy Alloys (HEAs) have been reported to exhibit enhanced mechanical and corrosion properties even at elevated temperatures. In this work, Al20Ti25Si25Mo20Ni10 HEA with outstanding corrosion and microhardness properties was developed by means of spark plasma sintering technique (SPS) was synthesized. The effect of sintering temperature was investigated on microstructure, densification, microhardness and corrosion resistance properties of the synthesized alloy. The microstructural evolution and phase identification were characterized 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 grains along with Mo, Ti and Si rich regions. No cracks or initiation of stress were revealed from the microstructures. Maximum relative densities of 98.4% resulted in microhardness of 960.09 HV were achieved at sintering temperature of 1000°C. The Ti25Si25 Al20Mo20Ni10 HEA fabricated at 1000°C displayed a higher polarization value of 3477 Ω.