Morphology-driven mechanical behavior of sintered titanium: A meso-scale numerical study

Abstract

The mechanical behavior of sintered microstructures is strongly influenced by their underlying morphology, particularly particle arrangement, size distribution, and inter-particle connectivity. In this study, a meso-scale numerical framework was developed to investigate the structure–property relationships of sintered titanium microstructures using randomly generated two-dimensional models. Nine representative configurations with varying overlap levels (5, 10, and 15 μm) were analyzed under directional loading conditions, resulting in a total of eighteen simulations. The results demonstrate, within the adopted two-dimensional meso-scale framework, that increasing particle overlap significantly enhances neck formation, leading to improved load transfer, higher stiffness, and increased strength. Specifically, the Young’s modulus increased from as low as 0.3 GPa in low-overlap cases to values exceeding 60 GPa in highly connected structures, while the ultimate strength reached up to 415 MPa. The coefficient of variation (CV), ranging from 0.15 to 0.30, was found to strongly influence mechanical performance, with higher values promoting heterogeneity, stress concentration, and strain localization. In contrast, increased connectivity (Z_av = 2.00–2.73) improved load distribution and mechanical stability by providing multiple load paths. To capture the combined effects of microstructural heterogeneity, a randomness index (RI = 0.07–0.14) was introduced as a unified descriptor. The RI showed a strong inverse correlation with both stiffness and strength, outperforming individual parameters such as CV and connectivity. Furthermore, the mechanical response was found to be highly anisotropic, with stiffness ratios (E_y/E_x) varying from 0.01 to 4.22 depending on microstructural topology and loading direction. Overall, the findings highlight the critical role of morphology in governing the mechanical performance of sintered microstructures and provide a systematic framework for the design of materials with tailored properties.