Commingled fiber preform architecture for high temperature composites

A porous fiber preform comprising:

• a first fabric layer, wherein the first fabric layer comprises first fugitive fibers, first carbon fibers, and first fusible fibers and wherein a percentage of the first carbon fibers together with a percentage of the first fusible fibers in the first fabric layer is larger than a percentage of the first fugitive fibers in the first fabric layer;
• a second fabric layer, wherein the second fabric layer comprises second fugitive fibers, second carbon fibers, second first fusible fibers, wherein a percentage of the second carbon fibers together with a percentage of the second fusible fibers in the second fabric layer is larger than a percentage of the second fugitive fibers in the second fabric layer, and wherein the percentage of the second carbon fibers, the percentage of the second fusible fibers, and the percentage of the second fugitive fibers in the second fabric layer is different from the percentage of the first carbon fibers, the percentage of the first fusible fibers, and the percentage of the first fugitive fibers in the first fabric layer;
• a third fabric layer, wherein the third fabric layer comprises third fugitive fibers, third carbon fibers, third first fusible fibers, wherein a percentage of the third carbon fibers together with a percentage of the third fusible fibers in the third fabric layer is larger than a percentage of the third fugitive fibers in the third fabric layer, and wherein the percentage of the third carbon fibers, the percentage of the third fusible fibers, and the percentage of the third fugitive fibers in the third fabric layer is different from the percentage of the first carbon fibers, the percentage of the first fusible fibers, and the percentage of the first fugitive fibers in the first fabric layer;
• and
• a fourth fabric layer, wherein the fourth fabric layer comprises fourth fugitive fibers, fourth carbon fibers, and fourth fusible fibers, wherein a percentage of the fourth carbon fibers together with a percentage of the fourth fusible fibers in the fourth fabric layer is larger than a percentage of the fourth fugitive fibers in the fourth fabric layer, and wherein the percentage of the fourth carbon fibers, the percentage of the fourth fusible fibers, and the percentage of the fourth fugitive fibers in the fourth fabric layer are different from the percentage of the second carbon fibers, the percentage of the second fusible fibers, and the percentage of the second fugitive fibers in the second fabric layer and the percentage of the third carbon fibers, the percentage of the third fusible fibers, and the percentage of the third fugitive fibers in the third fabric layer,
• wherein the second fabric layer and the third fabric layer are positioned between the first fabric layer and the fourth fabric layer,
• wherein the second fabric layer, the third fabric layer, and the fourth fabric layer are joined to the first fabric layer via through thickness reinforcement (TTR) using a commingled thread thereby forming a fiber preform,
• wherein a transport depth of the TTR penetrates completely through a thickness of the first fabric layer and partially through a thickness of one or more of the second fabric layer, the third fabric layer, or the fourth fabric layer,
• wherein, prior to pyrolysis, the commingled thread comprises fifth carbon fibers commingled with fifth fugitive fibers and fifth fusible fibers,
• wherein a ratio of the fifth fugitive fibers to the fifth carbon fibers to the fifth fusible fibers is 1:to at least 2:to at least 2,
• wherein, during pyrolysis, the first fugitive fibers, the second fugitive fibers, the third fugitive fibers, the fourth fugitive fibers, and the fifth fugitive fibers are pyrolyzed from the commingled fiber preform to create a path through the thickness for infiltration of fluids thereby forming the porous fiber preform, and
• wherein, during the pyrolysis, the first fusible fibers, the second fusible fibers, the third fusible fibers, the fourth fusible fibers, and the fifth fusible fibers decompose leaving behind a carbon char that forms a carbon matrix of the commingled fiber preform.