In this study, we developed an Mg-, vacuum-, and pressure-free process for manufacturing Al-based composites via nitridation-assisted spontaneous infiltration of molten Al. In this process, the wettability between molten Al and ceramic reinforcement was significantly enhanced by nitridation via heating and surface modification of the Al particles; this provided a sufficient capillary force (i. e., negative curvature) for spontaneous infiltration of molten Al. The proposed process can generate composites based on Mg-free Al matrices and is relatively versatile in terms of the type, volume fraction, and morphology of the reinforcement material. Furthermore, the properties of the final composites can be modified by controlling their degree of nitridation, thereby expanding the material scope and their corresponding application fields.