Fabrication of iron-based amorphous reinforced CoCrNi medium-entropy alloys by selective laser melting: Enhancement of mechanical properties and improvement of corrosion resistance

Abstract

Due to their exceptional mechanical characteristics and corrosion resistance, CoCrNi medium-entropy alloys have been the subject of increasing interest in recent years. In this study, CoCrNi medium entropy alloys strengthened with iron-based amorphous materials were fabricated using Selective Laser Melting (SLM) technology, with established gradients at 0, 3, 5, and 7 wt%. At room temperature, the yield strength and hardness of the CoCrNi-5MG specimen showed marked improvements of 27.5 % and 34.7 % respectively, compared to its pure CoCrNi counterpart, while still preserving a considerable fracture elongation of 24 %. Under low-temperature conditions, all samples prepared via Selective Laser Melting (SLM) demonstrated significant improvements in yield strength and fracture plasticity. Furthermore, the CoCrNi samples doped with iron-based amorphous material exhibited superior low-temperature performance, with the increase in plasticity exceeding that of the Pure CoCrNi samples compared to room temperature conditions. Importantly, an increase in the content of iron-based amorphous material resulted in a decrease in the corrosion current density, thereby noticeably enhancing corrosion resistance. Our study proposes an innovative approach to enhancing the strength and corrosion resistance of CoCrNi medium-entropy alloys. This is achieved by incorporating iron-based amorphous materials during the SLM preparation process, thereby providing a new avenue for optimizing its properties.