Corrosion and thermal behaviour of AlCr1.5CuFeNi2Tix high-entropy alloys

Abstract

The high entropy alloys (HEAs) are capable to form simple solid solution and hence are the most favourable choice for high temperature applications. Till now, the research on HEAs is based on exploring the various properties of equimolar or near equimolar alloys consisting of almost similar elements. However, the corrosion behaviour of most of the novel high–entropy alloys is yet to be studied. The purpose of this study is to investigate the effect of Ti on the corrosion and thermal behaviour of AlCr1.5CuFeNi2Tix (x = 0, 0.25, 0.5, 0.75,1 in molar ratio) alloys. The AlCr1.5CuFeNi2TixHEAs samples were cast by high temperature vacuum induction furnace under inert gas environment. The electrochemical-corrosion behaviour of the alloys immersed in 3.5 wt.% NaCl solution was studied by potentiodynamic-polarization method. The results show that the addition of Titanium improves the corrosion resistance of as-cast alloys. The minimum and maximum value of corrosion rate is found to be 0.068 and 0.300 mmpy for Ti0 and Ti0.75 respectively. The thermal conductivity of the alloy was determined by hot disk thermal constant analyser at various temperatures varying from 300 K to 500 K. The thermal conductivity of the alloy decreases with the increase in Titanium content but on the contrary the thermal conductivity increases with increasing temperature.