This work focused on developing an analytical fast and reliable model to predict the morphological changes in nanocomposite powders during mechanical alloying. A conceptual dynamic model was developed and applied to predict the particle size of magnesium-based hybrid composite powder reinforced with Ti and SiC fabricated by mechanical alloying. The effect of milling time on the morphology, microstructure, and particle size of composite powders was investigated. The experimental and model predictions demonstrated that the optimal milling times varies between pure metal, duel matrix alloy and duel-matrix nanocomposite because it was obtained as 32 h for Mg milled, 16 h for Mg-30 wt% Ti and Mg- 20 wt% Ti- 10 wt% SiC nanocomposite with an average particle size 4.91 μm, 6.95 μm, and 5.38 μm, respectively. Prediction results by the CD model for the mentioned samples were equal to 5.33 μm, 6.7 μm, and 6.04 μm, respectively. By increasing the time of ball milling, the crystalline structure of SiC from changed hexagonal to cubic. Another effect of increasing time occurred on the crystallite size and caused the largest decrease, which was equal to 61.91%, to occur for composite Mg-Ti-SiC.