Room and Elevated Temperature Sliding Friction and Wear Behavior of Al0.3CoFeCrNi and Al0.3CuFeCrNi2 High Entropy Alloys

Abstract

In this study, processing–structure–property relations were systematically investigated at room and elevated temperatures for two FCC Al0.3CoFeCrNi and Al0.3CuFeCrNi2 high-entropy alloys (HEAs), also known as complex concentrated alloys (CCAs), prepared by conventional arc-melting. It was determined that both alloys exhibit FCC single-phase solid solution structure. Micro-indentation and sliding wear tests were performed to study the hardness and tribological behavior and mechanisms at room and elevated temperatures. During room-temperature sliding, both alloys exhibit similar friction behavior, with an average steady-state coefficient of friction (COF) of ~0.8. Upon increasing sliding temperatures to 300 °C, the average COF decreased to a lowest value of ~0.3 for Al0.3CuFeCrNi2. Mechanistic wear studies showed this was due to the low interfacial shear strength tribofilms formed inside the wear tracks. Raman spectroscopy and energy dispersive spectroscopy determined the tribofilms were predominantly composed of binary oxides and multi-element solid solution oxides. While the tribofilms at elevated temperatures lowered the COF values, the respective wear rates in both alloys were higher compared to room-temperature sliding, due to thermal softening during 300 °C sliding. Thus, these single FCC-phase HEAs provide no further benefit in wear resistance at elevated temperatures, and likely will have similar implications for other single FCC-phase HEAs.

Microstructure and Friction Properties of AlCrTiVNbx High-Entropy Alloys via Annealing Manufactured by Vacuum Arc Melting

“…Additionally, the alloy exhibits improved resistance to dislocation at grain boundaries, resulting in a 26% increase in its hardness and enhanced wear resistance. The third way is to modify its surface structure through surface engineering technology [45], such as carburizing, nitriding and boronizing. For example, with Ni 45 (CoCrFe) 40 (AlTi) 15 surface nitriding [46], AlN, CrN and TiN phases are formed on the surface, effectively increasing the surface hardness of the alloy from 8.8 GPa to 14.9 GPa.…”

Comparative Analysis of Wear Behavior of High Entropy Alloy (TiVNbCrAl) and Ti-based Conventional Alloy (TiNbCrCoAl)

“…Alloys with a minimum of five components and component concentrations ranging from 5 to 35 at.% fall under this category of materials. A stable thermodynamically RESEARCH substitutional solid mixture with the starting bcc, fcc, or hcp structure is a distinctive feature of HEAs [4][5][6][7]. Using this method, we can create new alloys that have a Exceptional balance of toughness, elasticity, hardness, and resistance to wear.…”