Microstructural Pathways to Interface Stability in Al–SiC Metal Matrix Composites: Powder Metallurgy Versus Field‐Assisted Sintering/Spark Plasma Sintering Consolidation

Al–SiC metal matrix composites are widely used in lightweight structural and tribological applications; however, their performance is governed by chemical and microstructural stability of the Al–SiC interface. Despite extensive research, microstructural pathways controlling interface evolution under different consolidation routes remain insufficiently understood. In this work, a novel microstructure‐driven framework is proposed to describe interface evolution in Al–SiC composites processed by powder metallurgy (PM) and field‐assisted sintering/spark plasma sintering (FAST/SPS). The two routes are identified as distinct thermal–kinetic regimes, leading to fundamentally different interface development mechanisms. PM processing results in diffusion‐controlled evolution characterized by residual porosity (≈91–94% relative density), oxide‐stabilized particle contacts, and a tendency for continuous interfacial reaction layers. In contrast, FAST/SPS enables rapid, pressure‐assisted densification (up to ≈99.6% relative density), accompanied by oxide fragmentation, particle rearrangement, and improved particle–matrix bonding, even at high reinforcement fractions. Although localized Al 4 C 3 formation is observed in both cases, reaction products remain spatially limited under kinetically constrained FAST/SPS conditions. Hardness, transverse rupture strength, and dry sliding wear confirm that interface integrity governs macroscopic performance, with FAST/SPS composites exhibiting improved wear resistance. Proposed relationships provide a unified framework for understanding consolidation‐dependent interface evolution and guiding design of Al–SiC composites with stable interfaces.