Metal matrix composites (MMCs) are attractive structural materials due to their potential for tailoring mechanical properties through microstructural design [1]. Powder metallurgy is a widely used fabrication route for MMCs, in which mixed metallic powders are cold-compacted and subsequently sintered. The cold compaction stage governs the evolution of porosity, particle arrangement, and inter-particle contact, and therefore plays a critical role in determining the final effective properties of the composite. Accurate prediction of the compaction curve—relating applied pressure to relative density—is thus essential for controlling green body quality and ensuring reproducible sintering outcomes. In the present study, the cold compaction behavior of Zr–Nb powder mixtures is investigated using micromechanical finite element modeling [2]. Nb contents ranging from 0 to 30 wt.% were considered. A unit-cell–based approach was employed to predict pressure–density relationships for different compositions. The numerical models underwent rigorous verification through mesh convergence studies and were validated by comparison with experimental compaction data. Beyond composition effects, the model was used to systematically quantify the influence of key micromechanical parameters on the compaction curve, including inter-particle friction coefficient, particle shape, and particle size distribution. The results demonstrate that variations in Nb content significantly affect porosity evolution and particle rearrangement mechanisms, while friction, morphology, and size dispersion strongly influence the slope and curvature of the compaction response. The study highlights the importance of accurately determining the compaction curve as a prerequisite for predictive powder metallurgy design. The proposed modeling framework provides a robust tool for linking powder-scale characteristics to macroscopic compaction behavior, enabling improved control over green body microstructure prior to sintering.