Experimental investigation of the isopleth NbAl3-VAl3 of the Al-Nb-V system

Abstract

Since the beginning of the 21st century, a new concept of alloy development has attracted the interest of the scientific community. These are alloys with multi principal elements, which are known as high entropy alloys. Considering their potential application at high temperature, refractory metals have been used as constituents of such alloys, known as refractory high entropy alloys. Further development of these alloys considers the addition of aluminum to refractory high entropy alloys with the objective of reducing their density, a critical point for the aerospace industry. A preliminary study of the phase relations involving refractory metals and aluminum is therefore necessary, given their chemical dissimilarity. In this context one of the systems of interest is the ternary Al-Nb-V, which has received little attention so far. The investigation of this system was initiated in the master project of Júlio César Pereira dos Santos, who studied the isothermal section at 1200 °C and conducted a preliminary thermodynamic modeling of the system from microstructural characterization of as-cast and heat treated samples. The present study aims at the determination of the isopleth NbAl3 and VAl3 to contribute to the investigation of the complete ternary system. Samples will be arc-melted and heat treated at 1200 °C and 1000 °C in order to achieve thermodynamic equilibrium. All samples will be microstructurally characterized by means of X-ray diffraction (XRD), scanning electron microscopy (SEM) and electronic microanalysis (EDS).