A number of variations may include a product that may include a final part that may include a first part that may include a first face and may define at least one through hole and a second part that may include a second face, at least one stake, and at least one energy director that may be disposed between the first face and the second face wherein the first face and the second face may be abutted against one another and the at least one stake may be passed through the at least one through-hole and the first part and the second part have been ultrasonically staked and ultrasonically welded such that an ultrasonically welded interface may be formed between the first part and the second part.

A number of variations may include a product that may include a final part that may include a first part that may include a first face and may define at least one through hole and a second part that may include a second face, at least one stake, and at least one energy director that may be disposed between the first face and the second face wherein the first face and the second face may be abutted against one another and the at least one stake may be passed through the at least one through-hole and the first part and the second part have been ultrasonically staked and ultrasonically welded such that an ultrasonically welded interface may be formed between the first part and the second part.

Methods of making a carbon-carbon composite structure with internal microchannels include (i) assembling a dry carbon fiber composite preform with a sacrificial template woven or placed within to form a primary assembly; (ii) placing the primary assembly under a sealed enclosure; (iii) applying a vacuum to the sealed enclosure to evacuate air from the dry carbon fiber composite preform; (iv) infusing a polymer resin into the dry carbon fiber composite preform to generate a resin infused preform; (v) heating the resin infused preform under vacuum to cure the polymer resin in the resin infused preform to form a cured composite; (vi) demolding the cured composite; and (vii) heating the cured composite to an elevated temperature of at least 800 C. under a flow of an inert gas to decompose the sacrificial template to form the internal microchannels and carbonize the cured composite to form the carbon-carbon composite structure.