Our study proposes in situ synthesis of cold-rollable aluminum nitride (AlN) reinforced aluminum matrix composites with attractive thermal properties via arc plasma-induced accelerated volume nitridation (APAVN). Within three minutes of repeated APAVN using commercial nitrogen gas, volume fraction of AlN increased up to 40 vol%, which is the highest value ever reported by in situ nitridation of pure aluminum. The composites contained homogeneously dispersed AlN particulates with strong interfacial bonding and low interfacial thermal resistance, which resulted in unique combination of a relatively low coefficient of thermal expansion and high specific thermal conductivity. APAVN resulted from instantaneous chemisorption of dissociated nitrogen, enhanced diffusion of dissolved nitrogen, and improved wettability, which led to much more AlN formation, ∼2.94 × 10−1 g/(min cm3), which is about 400 times higher than that in the gas bubbling method. These results would ultimately give us a promising strategy for continuous production of in situ Al–AlN composites for heat sink applications through cost-effective processing.