A ceramic matrix composite article includes a melt infiltration ceramic matrix composite substrate comprising a ceramic fiber reinforcement material in a ceramic matrix material having a free silicon proportion, and a chemical vapor infiltration ceramic matrix composite outer layer comprising a ceramic fiber reinforcement material in a ceramic matrix material having essentially no free silicon proportion disposed on an outer surface of at least a portion of the substrate.

Provided herein are methods of making composite materials. The methods may include infiltrating a carbon nanoscale fiber network with a ceramic precursor, curing the ceramic precursor, and/or pyrolyzing the ceramic precursor. The infiltrating, curing, and pyrolyzing steps may be repeated one or more times. Composite materials also are provided that include a ceramic material and carbon nanoscale fibers.

Rotor assemblies and methods for manufacturing airfoils for rotor assemblies are provided. For example, a rotor assembly comprises a rotary structure extending circumferentially about an axial centerline of a gas turbine engine and an airfoil having a root and a tip. The root is coupled to the rotary structure and has a bulbous shape. The airfoil is formed from a plurality of composite plies, a portion of which defines at the root first and second end surfaces, which are in contact with the rotary structure and together define a chisel-shaped end of the root. In another embodiment, a rotor assembly comprises an outer rotor extending circumferentially about an axial centerline of a gas turbine engine and a composite outer rotor blade having a root and a tip. The blade root is coupled to the outer rotor and extends inward along a radial direction toward the axial centerline.

A non-woven fabric is provided which includes a three-dimensional array of fibers. The three-dimensional array of fibers includes an array of standing fibers extending perpendicular to a plane of the non-woven fabric and attached to a base substrate, where the base substrate is one or more of an expendable film substrate, a metal base substrate, or a mandrel substrate. Further, the three-dimensional array of fibers includes multiple layers of non-woven parallel fibers running parallel to the plane of the non-woven fiber in between the array of standing fibers in a defined pattern of fiber layer orientations. In implementation, the array of standing fibers are grown to extend from the base substrate using laser-assisted chemical vapor deposition (LCVD).

A method is provided in which multiple layers are formed. Each of the layers includes at least a first set of ceramic fibers and a second set of ceramic fibers. The first set is arranged at an angle with respect to the second set. The first set and the second set define a plurality of pores therebetween. The layers are arranged on top of each other to form a porous preform. The pores of the layers arranged on top of each other are aligned. The pores define a plurality of channels extending continuously through the porous preform from a first side of the porous preform to a second side of the porous preform. Each channel comprises one inlet at the first side of the porous preform and one outlet at the second side of the porous preform. The porous preform is infiltrated with a matrix material.

Provided herein is a method of making a conductive network by combining uncoated carbon nanotubes and carbon nanotubes coated with an electroactive substance to create an electrically conductive network; and redistributing at least a portion of the electroactive substance. Also provided herein is an electrically conductive network with an active material coating; first carbon nanotubes coated with the active material coating; and second carbon nanotubes partially coated with the active material coating, wherein at least a portion of the surfaces of the second carbon nanotubes directly contact surfaces of other second carbon nanotubes without the active material coating between these second carbon nanotubes, and wherein the first carbon nanotubes and the second carbon nanotubes are entangled to form an electrically conductive network.

A CMC article may include a CMC substrate defining a major surface and a plurality of CMC reinforcing pins at least partially embedded in the CMC substrate. Each CMC reinforcing pin of the plurality of CMC reinforcing pins defines a respective long axis. The respective long axes may be oriented at an angle substantially perpendicular to the major surface of the CMC substrate. A method may include inserting a plurality of CMC reinforcing pins into a major surface of a ceramic fiber preform. Each CMC reinforcing pin of the plurality of CMC reinforcing pins defines a respective long axis. As the plurality of CMC reinforcing pins are inserted into the major surface, the respective long axes may be oriented at an angle substantially perpendicular to the major surface. The method also includes forming a matrix of material within pores of the ceramic fiber preform to form a CMC article.

A seed crystal holder for pulling up a single crystal is made of a carbon fiber-reinforced carbon composite material, and has a substantially cylindrical shape with a hollow space having a shape matching an outer shape of a substantially rod-shaped seed crystal. A direction of carbon fibers at a part in contact with at least an outer peripheral surface of the seed crystal has isotropy as viewed from a central axis of the hollow space.

Disclosed are an inorganic nanofiber characterized in that the average fiber diameter is 2 m or less, the average fiber length is 200 m or less, and the CV value of the fiber length is 0.7 or less; and a method of manufacturing the same. In the manufacturing method, an inorganic nanofiber sheet consisting of inorganic nanofibers having an average fiber diameter of 2 m or less is formed by electrospinning, and then, the inorganic nanofiber sheet is pressed using a press machine and crushed so that the average fiber length becomes 200 m or less, and the CV value of the fiber length becomes 0.7 or less.

A method for fabricating a component according to an example of the present disclosure includes the steps of depositing a stoichiometric precursor layer onto a preform, and densifying the preform by depositing a matrix material onto the stoichiometric precursor layer. An alternate method and a component are also disclosed.