Tailoring the Microstructure and Mechanical Properties of Laser Powder-Directed Energy-Deposited Inconel 625 Using Scan Strategies

Abstract

The current study is focused on the influence of different scan strategies on the microstructural evolution, crystallographic texture, and mechanical properties of the Inconel 625 (IN625) fabricated using the laser powder-directed energy deposition (LP-DED) process. Prior to the deposition of the bulk specimens, an optimized set of process parameters (laser power (P), scan speed (v), and feed rate (f)) was selected through analysis of single-track deposits. The single tracks were thoroughly analyzed based on the aspect ratio, track stability, dilution, and shape of the melt pool. Further, six rectangular blocks of IN625 with different scan strategies (unidirectional ? 0°, bidirectional ? 0°, 45°, 67°, 90°, and spiral) were fabricated using the optimized process parameters for deposition. Samples with a 0° unidirectional scan strategy exhibited higher yield strength values but lower ductility. Notably, the sample with a scan orientation of 67° exhibited superior isotropic properties that are required to bear intense multi-axial loads when compared to other samples. The results indicated that the sample with a 67° scan orientation has the best combination of both strength and ductility. This can be attributed to finer cells/grains, which occur due to fragmentation of cells/grains during their growth across the successive layers, a higher fraction of low-angle grain boundaries (LAGBs), and variation of vector length within a layer. EBSD analysis revealed that samples with a 67° scan orientation exhibited a random crystallographic texture (MUD = 2.2), which suggests isotropic behavior compared to other samples. © ASM International 2025.