Micromechanical Characterization of 316L‐V4E Steel Transitions Produced by Electron Beam Powder Bed Fusion with Dual‐Hopper Alternating Layer Strategy

This work investigates microstructural and mechanical transitions in multi‐material assemblies of American iron and steel institute 316L stainless steel and V4E tool steel, fabricated using a dual‐hopper layer alternation strategy via electron beam powder bed fusion (PBF‐EB). Two types of layered transitions are produced: alternating transition and alternating incremental transition (AIT). The assemblies are characterized using electron backscattered diffraction and high‐speed nanoindentation (HSN), with mechanical phases extracted via Gaussian mixture modeling applied to nanoindentation maps. In the alternating layer sample, localized mechanical features are identified within the elongated austenite grains of 316L, and V4E is observed growing along grain boundaries at the interphase. In the AIT sample, similar interfacial features are observed, but the gradual addition of V4E layers generates a continuous mechanical gradient. Nanoindentation maps reveal increasing hardness and elastic modulus along the transition, ultimately reaching homogenized mechanical behavior in the V4E region. The study demonstrates the feasibility of producing compositionally graded steel assemblies with robust interfaces using PBF‐EB. It also emphasizes the value of HSN combined with statistical clustering to resolve micromechanical heterogeneities, enabling more precise design and optimization of advanced multi‐material systems.