Microstructure and Mechanical Properties of FeCoNiCrAlx High-entropy Alloys by Selective Laser Melting

In this study, the thermal analysis theory of selective laser melting (SLM) was introduced, and different high-entropy alloy (HEA) specimens were prepared using the SLM technology. The effects of different powder sizes, elemental contents, and process parameters on the microstructure and mechanical properties of FeCoNiCrAl_x HEA specimens fabricated using SLM were analyzed. Moreover, hardness and tensile tests of these high-entropy alloys were performed. The results showed that with increasing laser power and hatch spacing, the hardness of the specimens initially increased and subsequently decreased; it also increased with increasing scanning speed. The FeCoNiCrAl_0.5 HEA specimens prepared using fine powder exhibited better tensile properties, followed by FeCoNiCrAl_0.8 HEA. However, the FeCoNiCrAl_0.5 HEA prepared using coarse powder exhibited the poorest tensile properties. A comparison of the tensile properties of the specimens at different heights revealed that the specimens formed at the middle height exhibited improved tensile properties.