An article comprises a first member comprising a first carbon composite; and a second member disposed on the first member and comprising a second carbon composite and a reinforcing agent, wherein the second member has a gradient in the weight ratio of the second carbon composite to the reinforcing agent, and wherein the first member has one or more of the following properties different than those of the second member: elasticity; corrosion resistance; erosion resistance; or hardness.

In some examples, a method including depositing a resin and a plurality of carbon fibers via a print head of a three-dimensional printing system to form a carbon fiber preform including a plurality of individual carbon fiber layers, wherein each individual layer of the plurality of individual carbon fiber layers includes the resin and carbon fibers, and wherein the carbon fiber preform exhibits at least one of a non-uniform composition of the resin within the preform, different types of the carbon fibers within the preform, or non-uniform fiber orientation within the preform.