In situ synthesis of titanium alloy powders reinforced with nanoparticles for powder bed fusion: A step towards safer and more sustainable manufacturing

Abstract

Additive manufacturing technologies for metallic materials based on powder bed fusion, either with electron (PBF-EB/M) or laser beam (PBF-LB/M) have enormous industrial potential. It is known that the reinforcement of nanoparticles in the metallic matrix improves the mechanical properties. This study presents a novel method for manufacturing reinforced powder particles for PBF technology. The method involves dispersing and dissolving reinforcing nanoparticles in the metallic matrix, resulting in a composite material. The method was applied to a Ti‐6Al‐4V matrix with SiC nanoparticles as reinforcement to develop a new Titanium Matrix Composite (TMC). A route for atomizing the composite material has been developed to scale up the process on an industrial level. The atomized material has been designed to be used as feedstock with PBF-EB/M and PBF-LB/M. The feedstock is a composite powder obtained by the Electrode Inert Gas Atomization (EIGA) process after mixing and dispersing SiC nanoparticles in the Ti‐6Al‐4V matrix and consolidating the mixture into an ingot bar using Hot Isostatic Pressing (HIP). The powder bed fusion process parameters have been studied to obtain specimens with a density greater than 99.9%, and close to 100% after HIP process. The conditions for some heat treatments, such as HIP and stress relief, have been determined. The conditions of machining processes, such as milling and turning, have been studied. The material’s properties, such as chemical composition, microstructure, mechanical strength, and fatigue behavior have been evaluated. Compared to Ti‐6Al‐4V according to the ASTM F2924 standard, both the ultimate tensile strength and yield strength have been improved by 28%, and the elongation at break by between 30% and 60%. Regarding fatigue behavior, an increase of around 30–50% (high-low cycles) has been observed.