Microstructure-property-performance relationships in the orientation-driven vibrational behavior of LPBF AlSi10Mg specimens

This study presents an experimental investigation of the vibrational behavior of AlSi10Mg specimens manufactured by laser powder bed fusion (LPBF), linking dynamic performance to porosity characteristics and build orientation (BO). Beam-like specimens were produced in upright and on-edge BOs and tested under sinusoidal base excitation using an electrodynamic shaker combined with a laser Doppler vibrometer. Two clamping configurations (CCs), referred to as short-length (SL) and long-length (LL), were adopted to probe the influence of boundary stiffness on resonance and damping behavior. X-ray computed tomography (CT) revealed dense microstructures with low porosity fractions (∼0.35 % for on-edge and ∼0.55 % for upright BOs), but orientation-dependent differences were evident. Large defects clustered at shell-core interfaces, consistent with contour-hatch transition zones, while upright specimens exhibited more frequent and elongated pores. Frequency response functions showed sharp, reproducible resonance peaks, underscoring the robustness of LPBF. Upright specimens resonated at ∼452 Hz (SL) and ∼582 Hz (LL), while on-edge ones resonated at ∼455 Hz (SL) and ∼595 Hz (LL). All measured frequencies were lower than Euler-Bernoulli predictions due to fixture compliance and effective free-length deviations. Damping ratios (ξ) ranged from 0.0043 to 0.0049, corresponding to a quality factor of ∼100–116. Orientation effects, though secondary to geometry and CC, were systematic: upright BOs exhibited slightly higher ξ in SL, whereas on-edge BOs showed higher ξ under LL. These results establish robust microstructure-property-performance relationships for vibration-critical LPBF AlSi10Mg components.