Impact of rhenium addition on microstructural characteristics and mechanical performance in Powder Bed Fusion-Laser Beam produced Inconel 625 alloy

Recent studies have highlighted the beneficial role of rhenium in enhancing the properties of superalloys. Even a slight alloying addition of rhenium can lead to a significant improvement in mechanical properties, particularly at elevated temperatures. This finding is particularly intriguing in the context of powder-based additive manufacturing techniques, which enable the utilization of powder mixtures to create metal matrix composites (MMCs) or facilitate in situ alloying. The primary objective of the current research was to examine the impact of rhenium on the powder bed fusion-laser beam (PBF-LB) process of IN 625, a specific alloy. Despite its limited solubility in the as-built state, the addition of rhenium was found to have a notable influence on increasing the ultimate tensile strength (UTS). This effect became even more pronounced after heat treatment (solution treatment), which induced a higher dispersion of rhenium and other precipitates within the material. The experimental results demonstrated that the specimen with the addition of rhenium exhibited a remarkable UTS of 900 MPa, in contrast to the 700 MPa exhibited by the wrought material. This research clearly showcases that, despite its poor dispersion characteristics, the incorporation of rhenium can lead to a substantial increase in the strength of the material.