Development of spark plasma sintered TiAlSiMoW multicomponent alloy: Microstructural evolution, corrosion and oxidation resistance

• Published in: Results in physics 2019-03, Vol.12, p.1754-1761
• Main Authors: Rudolf Kanyane, L., Patricia Popoola, A., Malatji, Nicholus
• Format: Article
• Language: English
• Subjects: Corrosion resistant; High entropy alloys (HEAs); Oxidation resistant; Spark plasma sintering (SPS)
• ISSN: 2211-3797; 2211-3797
• DOI: 10.1016/j.rinp.2019.01.098

TiAlMoSiW high entropy alloy was fabricated using spark plasma sintering under different sintering temperatures. The microstructural and morphological characteristics of the alloy were investigated using X-ray diffractometry (XRD) and scanning electron microscope (SEM) equipped with energy dispersive spectroscopy (EDS). The mechanical and corrosion properties of the alloy were tested using diamond base indentor and potentiodynamic polarization. Thermogravimetric analysis and density measurements were used to check the thermal stability and densification of the samples. Microstructural analysis of the samples showed that the samples exhibited a bcc matrix with secondary phase precipitate of TiSi2. The microhardness was found to be subject to sintering temperature and densification with high microhardness values obtained 1000 °C and 98% densification. The presence of elements that form stable protective film were attributed to the high corrosion performance of the samples. These elements also form stable oxide scales in elevated temperatures improving the thermal stability of the alloy. Excessive oxidation was noticed to occur at temperatures above 535 °C showing that the alloy has superior thermal stability than Ti-6V-4Al.