Tribological Behavior of As-Cast and Aged AlCoCrFeNi2.1 CCA

In the present study, wear behavior as a function of aging time was evaluated for the AlCoCrFeNi2.1 eutectic complex, concentrated alloy (CCA) consisting of B2 (BCC), and L12 (FCC) lamellae in the as-cast state. By aging the material at 800 °C up to 500 h, precipitation of a fine, evenly dispersed micro-phase inside the L12 takes place. From 500 h to 1000 h of aging, precipitates coarsen by the Ostwald ripening mechanism. Reciprocating wear tests were characterized by a prevailing abrasive wear mechanism, while adhesive and delamination wear components change with aging conditions. The L12 phase with lower hardness in the as-cast material preferentially deformed during the wear test, which was not the case after aging the material, i.e., with the presence of precipitates. Aging-induced changes show a similar trend for the coefficient of friction and L12 + precipitates phase fraction, whereas changes in specific wear rate are in a good agreement with changes in B2 phase fraction. In general, aging the AlCoCrFeNi2.1 CCA at 800 °C up to 500 h decreases its coefficient of friction due to reduced adhesive wear component and enhances its wear performance through precipitation strengthening.