Abstract: Additive manufacturing apparatus and methods for mixing and dispensing materials, and articles with controlled particle concentrations. Additive manufacturing apparatus includes a mixer; a reservoir in fluidic communication with the mixer; and a build plate parallel to the reservoir. Additive manufacturing apparatus includes a mixer and a solid particle dispensing system and/or a slurry dispensing system. A method for handling precursors during additive manufacturing includes (a) providing first and second precursor materials and/or a slurry to a mixer; (b) mixing the materials in the mixer; (c) transporting the mixed materials directly to a reservoir disposed in parallel with a build plate; (d) curing at least a portion of the transported and mixed materials; and (e) repeating step (d) at least once. An article includes a plurality of adjacent layers, a concentration of particles in each layer defining a controlled concentration gradient and/or vary by no more than ±50%.