Chemical vapor infiltration tooling hole modification for optimizing infiltration in ceramic matrix composites
A tooling fixture suitable for use in infiltrating a fibrous preform with a reactant gas includes an outer surface and opposing inner surface defining a thickness therebetween, and a plurality of holes extending through the thickness. Each hole of the plurality of holes includes an inlet at the outer surface, the inlet configured to receive a flow of the reactant gas, an outlet at the inner surface, a transition point between the inlet and the outlet, and an angled segment extending from the transition point to the outlet. Each hole of the plurality of holes has a first diameter at the inlet and a second diameter at the outlet, and the second diameter is greater than the first diameter.
1 . A tooling fixture suitable for use in infiltrating a fibrous preform with a reactant gas, the tooling fixture configured to at least partially surround the fibrous preform and comprising:
an outer surface and opposing preform-facing inner surface defining a thickness therebetween, the preform-facing inner surface having a geometry to maintain a shape of the preform; and
a plurality of holes extending through the thickness, each hole of the plurality of holes comprising:
an inlet at the outer surface, the inlet configured to receive a flow of the reactant gas;
an outlet at the inner surface;
a transition point between the inlet and the outlet; and
an angled segment extending from the transition point to the outlet;
wherein each hole of the plurality of holes has a first diameter at the inlet and a second diameter at the outlet; and
wherein the second diameter is greater than the first diameter.
2 . The tooling fixture of claim 1 , wherein the first diameter is 0.125 in.
3 . The tooling fixture of claim 1 , wherein each hole of the plurality of holes is cylindrical between the inlet and the transition point.
4 . The tooling fixture of claim 3 , wherein each hole of the plurality of holes is at least partially frustoconical between the transition point and the outlet.
5 . The tooling fixture of claim 1 , wherein the angled segment defines a diffusion angle at the transition point, and wherein the diffusion angle ranges from 5° to 20°.
6 . The tooling fixture of claim 1 , wherein the tooling fixture is formed from at least one of graphite, a refractory metal alloy, a carbon-carbon composite, and a ceramic material.
7 . A tooling fixture suitable for use in infiltrating a fibrous preform with a reactant gas, the tooling fixture comprising:
an outer surface and opposing inner surface defining a thickness therebetween; and
a plurality of holes extending through the thickness, each hole of the plurality of holes comprising:
an inlet at the outer surface, the inlet configured to receive a flow of the reactant gas;
an outlet at the inner surface, wherein each hole of the plurality of holes is cylindrical between the inlet and the outlet with a uniform first diameter;
a transition point between the inlet and the outlet; and
at least one branching hole extending away from the hole between the transition point and the outer surface.
8 . The tooling fixture of claim 7 , wherein the at least one branching hole is cylindrical with a uniform second diameter.
9 . The tooling fixture of claim 8 , wherein the first diameter is greater than the second diameter.
10 . The tooling fixture of claim 7 , wherein the at least one branching hole comprises a plurality of branching holes.
11 . The tooling fixture of claim 7 , wherein the tooling fixture is formed from at least one of graphite, a refractory metal alloy, a carbon-carbon composite, and a ceramic material.
12 . A tooling fixture suitable for use in infiltrating a fibrous preform with a reactant gas, the tooling fixture comprising:
an outer surface and opposing inner surface defining a thickness therebetween; and
a plurality of holes extending through the thickness; each hole of the plurality of holes comprising:
an inlet at the outer surface; and
an outlet at the inner surface;
a first hole concentration at the outer surface, the first hole concentration being defined by an inlet diameter of each hole of the plurality of holes; and
a second hole concentration at the inner surface, the second hole concentration defined by an outlet diameter of each hole of the plurality of holes;
wherein the second hole concentration is greater than the first hole concentration;
wherein each hole of the plurality of holes is cylindrical between the inlet and the outlet,
and further wherein each hole of the plurality of holes comprises:
a transition point between the inlet and the outlet; and
an angled segment extending from the transition point to the outlet.
13 . The tooling fixture of claim 12 , wherein each hole of the plurality of holes is cylindrical between the inlet and the transition point.
14 . The tooling fixture of claim 13 , wherein each hole of the plurality of holes is at least partially frustoconical between the transition point and the outlet.
15 . The tooling fixture of claim 12 , wherein each hole of the plurality of holes comprises:
at least one branching hole extending away from the hole between the transition point and the outer surface;
wherein the at least one branching defines the angled segment.
16 . The tooling fixture of claim 12 , wherein the angled segment defines a diffusion angle at the transition point, and wherein the diffusion angle ranges from 5° to 20°.
17 . The tooling fixture of claim 12 , wherein the tooling fixture is formed from at least one of graphite, a refractory metal alloy, a carbon-carbon composite, and a ceramic material.