Comparison of microstructures, mechanical and tribological properties of Al_0.3CoCrFeNi high-entropy alloy prepared by induction melting and selective laser melting

Different preparation processes provide high-entropy alloys (HEAs) with distinct microstructures and properties, opening up a wider range of potential applications. In this work, Al0.3CoCrFeNi HEA is chosen as the reference alloy for understanding the effect of two different processes (induction melting and selective laser melting) on microstructures, mechanical and tribological properties. The as-cast sample exhibits coarse grains with a small amount of particles precipitated along grain boundaries. The as-printed sample exhibits heterogeneous microstructures and strong < 001 > preferred orientation. As compared to the as-cast sample (proof strength: 240 MPa, elongation: 56.5%), the as-printed sample shows a remarkable increment in proof strength (473 MPa) induced by refined grain strengthening and dislocation strengthening while a sharp drop of elongation (14.7%) induced by micropores, high-density dislocations, and residual stress. The tribological properties reveal that both the as-cast and as-printed samples exhibit the same wear mechanisms (abrasive wear and oxidative wear), while the as-printed sample with higher hardness shows superior wear resistance compared to the as-cast sample.