Needled brake disks and methods

A fibrous preform for an aircraft brake, comprising:

• two or more layers of oxidized polyacrylonitrile fiber (OPF) materials;
• an annulus formed from the two or more layers of OPF materials and having at least one of an outer diameter portion or an inner diameter portion, the outer diameter portion extending radially inward from an outer diameter of the fibrous preform and the inner diameter portion extending radially outward from an inner diameter of the fibrous preform;
• a medial diameter portion disposed between the outer diameter and the inner diameter,
• wherein the medial diameter portion comprises a first needling profile, and the outer diameter portion comprises a second needling profile,
• wherein the first needling profile and the second needling profile are co-planar,
• wherein the second needling profile is about 25% to 50% greater than the first needling profile,
• wherein first fiber tow lengths on a first layer of the OPF materials are angled in a first direction, and
• wherein second fiber tow lengths on a second layer adjacent the first layer of the OPF materials are angled in a second direction opposing the first direction,
• a heat affected zone disposed in the medial diameter portion, the heat affected zone configured to expand in response to an increase in temperature following a rejected take off,
• wherein the heat affected zone comprises a third needling profile, the third needling profile being about 25% to 50% less than the first needling profile, wherein the third needling profile and the second needling profile are co-planar.