Additive Manufacturing‐Induced Deformation Mechanisms in Co–Ni Superalloys Revealed by Integration of 3D EBSD and In Situ Digital Image Correlation

Laser powder bed fusion (LPBF) additive manufacturing produces components with unique microstructural features that significantly differ from conventionally processed materials, including columnar grain structures, intragranular orientation gradients, and elevated dislocation densities. However, the relationship between these complex microstructural characteristics and mechanical behavior, particularly deformation mechanisms at the grain scale, remains poorly understood. In this study, 3D electron backscatter diffraction characterization via TriBeam tomography and high‐resolution digital image correlation is performed to quantitatively compare the microstructure‐deformation relationships in wrought and LPBF processed GammaPrint‐700. The LPBF sample exhibits a 12% higher yield strength and elevated elastic modulus compared with the wrought material, which is attributed to increased grain boundary density, geometrically necessary dislocation (GND) density, and texture differences. Slip behavior differs markedly: The LPBF sample displays more homogeneous deformation, observed as a 200% higher slip trace density with 50% lower slip amplitudes compared with the wrought material, which exhibits localization along twin boundaries and triple junctions. These findings demonstrate that the complex thermomechanical history of LPBF creates inherent work hardening through GND accumulation and orientation gradients, while simultaneously delocalizing plastic strain. This delocalization mechanism suggests improved fatigue resistance in LPBF materials, providing new insights for processing‐structure‐property optimization in additively manufactured superalloys.