An increasing number of recent studies have indicated that the best balance of Bloat Formulas mechanical properties of a high-entropy alloy (HEA) needed to meet the requirements of practical structural applications require to produce second precipitates in an HEA matrix.This type of alloy is more appropriately classified as a complex concentrated alloy (CCA) rather than an HEA.Here, we report a simple strategy for the fabrication of CCA coatings with high mechanical properties.
In this strategy, the face-centred cubic (FCC)-based Co25Cr25Cu12.5Ni25Al12.5 (at.
%) system was chosen, and spark plasma sintering was first used to prepare the Co25Cr25Cu12.5Ni25Al12.5 CCA clad layer directly on a Q235 substrate from simple mixed powders.
Our results show that the CCA coating was fabricated successfully on the substrate and that the clad layer Module Learning Kit exhibited a dense microstructure, a low dilution ratio and good metallurgical bonding with the substrate.A high density of hierarchical intragranular nanoprecipitates was contained in the clad layer.Precipitation strengthening, as one of the main strengthening mechanisms, contributes to a microhardness value of 455 HV for the clad layer, which is much higher than those of most reported FCC-structured HEAs, even some BCC-structured refractory HEAs and several BCC-based HEAs with high Al contents.
Keywords: Complex concentrated alloy coating, Spark plasma sintering, Hierarchical nanoprecipitates, Precipitation strengthening, Mechanical properties.