Influence of Annealing on the Microstructures and Oxidation Behaviors of Al8(CoCrFeNi)92, Al15(CoCrFeNi)85, and Al30(CoCrFeNi)70 High-Entropy Alloys

Abstract

Abstract:The understanding of the oxidation behaviors of as-cast and annealed high-entropy alloys (HEAs) is currently limited. This work systematically investigates the influence of annealing on the microstructures and oxidation behaviors of AlCoCrFeNi-based HEAs. Annealing was found to alter the distribution of Al-rich phases which caused a change in the oxidation mechanisms. In general, all three of the investigated HEAs displayed some degree of transient oxidation at 1050 • C that was later followed by protective, parabolic oxide growth. The respective oxidation behaviors are discussed relative to existing oxide formation models for Ni-Cr-Al alloys.

Oxidation Behavior of Alx(CoCrFeNi)100-x High-Entropy Alloys Under Thermal-Cycling Conditions

“…All of the alloys were characterized by the parabolic oxide growth kinetics proceeded by a short initial transient oxidation. Further studies of the same group focused on the influence of thermal pre-treatment on the oxidation behavior of the alloys from the same system [26].…”

Phase Equilibria in the Al–Co–Cr–Fe–Ni High Entropy Alloy System: Thermodynamic Description and Experimental Study

“…High entropy alloys (HEAs) and, in particular, alloys from the Al-(Co)-Cr-Fe-Ni alloy system have been subject to numerous investigations due to promising mechanical, magnetic and electrochemical properties (Butler and Weaver, 2016;Gao et al, 2016;Chen et al, 2017;Shi et al, 2017). It was shown that in this alloy system the chemical composition can be adjusted to obtain materials with face centered cubic (FCC) or body centered cubic (BCC) majority phases (Wang et al, 2012(Wang et al, , 2014Yang et al, 2015).…”

Microstructural Impacts on the Oxidation of Multi-Principal Element Alloys

“…As the eld matures, more investigations are warranted on how traditional thermal and mechanical processing steps, which must take place from a manufacturing standpoint, will affect the microstructures and thus performance of the alloys from mechanical properties and oxidation resistance perspectives [11]. With regards to high temperature oxidation, most studies have either focused solely on the behavior of arc-melted microstructures that are known to have different bulk oxidation kinetics than homogenized and thermally processed materials [12] or have exclusively varied the bulk composition to achieve some microstructural changes [13][14][15][16][17]. In recent literature, there has been some focus on…”