Manufacturing-induced geometric deviations and corrosion-driven morphological evolution in magnesium lattice scaffolds.

Abstract

Manufacturing-induced geometric deviations were found to dominate the structural fidelity of lattice scaffolds, with the largest dimensional changes arising during the salt-to-metal transition. Subsequent corrosion exposure led to strut thinning while preserving global lattice architecture, indicating that fabrication-driven geometry establishes the baseline for degradation behavior. Truncated octahedron (TO) lattice scaffolds were produced using DLP-printed resin templates, NaCl sacrificial molds, and vacuum-assisted casting of AZ31 alloy. A micro-CT-based framework combining voxel-wise thickness mapping, histogram divergence metrics, and three-dimensional deviation analysis was used to quantify strut-level geometric evolution across fabrication stages and during corrosion exposure in DMEM. Resin templates exhibited a unimodal strut thickness distribution centered near 575 μm, corresponding to ∼4% shrinkage relative to the CAD design. As-cast scaffolds displayed a bimodal distribution with a primary mode of 653 μm, indicating an 8.8% increase associated with material redistribution at nodal regions. Spatial deviation maps revealed excess material at nodes and thinning along unsupported strut segments, with deviations ranging from -100 to +80 μm across the scaffold volume. Corrosion exposure resulted in progressive strut thinning, reflected by Jensen-Shannon divergence values of 0.194 at 48 h and 0.203 at 168 h and Mg²⁺ release, while preserving global architecture. The workflow enables quantitative tracking of structure evolution across manufacturing and degradation stages, supporting correlation between fabrication variability and time-dependent morphological stability in architected metallic scaffolds.