Mechanical properties of additively manufactured AlSi7Mg0.6 and IN718 thin-walled structures

Abstract Additively manufactured heat exchanger cores offer enhanced compactness, thermomechanical robustness, and improved integration within confined assembly spaces. However, their complex thin-walled lattice structures pose significant challenges for mechanical characterization and conventional finite element analysis, due to high computational costs. This study investigates the tensile mechanical properties of grid-like structures produced by powder bed fusion with a laser beam in aluminum alloy AlSi7Mg0.6 and nickel–chromium-based superalloy Inconel 718 (IN718). Samples with varying wall thicknesses were fabricated, heat treated, and some were surface treated to reduce surface roughness. Tensile tests combined with digital image correlation and non-linear finite element modeling were conducted to evaluate mechanical behavior. Experimental results reveal that a minimum solid material proportion (P s ≈ 0.09 for AlSi7Mg0.6; P s ≈ 0.06 for IN718) is required to achieve reliable elastoplastic deformation; below these thresholds, premature brittle failure dominates. Equivalent Young’s moduli and yield strength scale linearly with solid material proportion, the latter reaching approximately 59% and 52% of bulk material values for AlSi7Mg0.6 and IN718, respectively. Surface treatment contributed mainly to wall thickness reduction without significantly altering mechanical performance. Homogenized porous material models based on the Gibson–Ashby framework and a modified Hockett–Sherby constitutive law were developed, enabling efficient and realistic simulation of these complex structures. These findings provide critical experimental data and modeling tools essential for the design and optimization of next-generation additively manufactured heat exchangers in both alloys.