Spatially Resolved Mechanical Properties of Laser Powder Bed Fused Inconel 718 by Micro-Tensile Testing: Influence of Thermal History and Microstructure

Abstract Laser Powder Bed Fusion (L-PBF) fabricates three-dimensional parts through sequential layer deposition and melting. Each layer undergoes repeated thermal cycles, resulting in anisotropy and microstructural heterogeneity, which complicates part qualification. Characterizing this spatial variability using conventional mechanical tests requires numerous large specimens and is therefore costly and time-consuming. This study introduces a micro-scale testing framework to evaluate the local mechanical behavior of as-built L-PBF Inconel 718 parts. Miniature tensile specimens (3 mm × 1 mm × 0.25 mm) extracted from selected locations in four L-PBF geometries were used to determine local elastic modulus, yield strength, ultimate tensile strength, and strain to failure. Local mechanical properties were correlated with microstructural parameters and thermal history metrics. Significant spatial variability in mechanical properties was observed within the individual part and among the four geometries. The observed variability was more strongly correlated with thermal history metrics followed by microstructural parameters. The proposed approach enhances understanding of spatial heterogeneity in L-PBF parts and provides a basis for incorporating location-specific properties into component qualification and performance assessment.