Coating systems on a surface of a CMC component, such as a CMC shroud, are provided. The coating system can include an environmental barrier coating on the surface of the CMC component and an abradable coating on the environmental barrier coating and defining an external surface opposite of the environmental barrier coating. The abradable coating includes a compound having the formula: Ln.sub.2ABO.sub.8, where Ln comprises scandium, yttrium, lanthanum, cerium, praseodymium, neodymium, promethium, samarium, europium, gadolinium, terbium, dysprosium, holmium, erbium, thulium, ytterbium, lutetium, or mixtures thereof; A comprises Si, Ti, Ge, or a combination thereof; and B comprises Mo, W, or a combination thereof. In one embodiment, the abradable coating has a first coefficient of thermal expansion at an interface with the environmental barrier coating that changes to a second coefficient of thermal expansion at its external surface. Methods are also provided for applying an abradable coating onto a CMC component.

A blade has an attachment root and an airfoil, the airfoil having a proximal end and a distal end. The blade has a compositional variation along the airfoil.

According to one embodiment of this disclosure a core includes a first end and a second end spaced generally opposite from the first end. The core further includes a stacking axis defined between the first end and second end and a first toroidal structure located between the first end and the second end. The first toroidal structure includes a first passage extending through the first toroidal structure in a first direction that is perpendicular to and passes through the stacking axis. The core also includes a second toroidal structure located between the first toroidal structure and the second end. The second toroidal structure includes a second passage extending through the second toroidal structure in a second direction. The first direction and the second direction are oriented along the stacking axis at a non-zero degree angle with respect to each other.

A method is provided for casting an article such as a blade having an attachment root and an airfoil, the airfoil having a proximal end and a distal end. The method comprises introducing a molten alloy into a mold; and varying a composition of the introduced alloy during the introduction so as to produce a compositional variation.

Methods and materials for forming in-situ features in a ceramic matrix composite component are described. The method of forming a ceramic matrix composite component with cooling features, comprises forming a preform tape, laying up said preform tape to a desired shape, placing a high-temperature resistant fugitive material insert of preselected geometry in the preform tape of the desired shape, compacting the preform tape of the desired shape, burning out the preform tape of the desired shape, melt infiltrating the desired shape, removing the high-temperature resistant insert to form the cooling features during one of the burning out or the melt infiltrating or following the burning out or the melt infiltrating.

A method is provided for casting an article such as a blade having an attachment root and an airfoil, the airfoil having a proximal end and a distal end. The method includes introducing a molten alloy into a mold. A composition of the introduced alloy is varied during the introduction so as to produce a compositional variation.

A part formed using an metal additive manufacturing process such as a turbine airfoil with an oversized feature such as an oversized hole, where the oversized hole is filled with a preform having a shape of a normal sized hole and secured within the part using a braze or weld material, and where the preform is removed to leave within the part the normal sized hole. The preform is made of a refractory material that can be removed from the part by exposure to oxygen.

A method for forming a gas turbine engine component comprises the steps of forming a block of a high temperature alloy material. An external surface of the block is machined to form an external surface of a gas turbine engine component. At least one cooling passage within the component that is open to at least one end of the component is machined. At least one insert with a heat transfer feature is formed. The insert is installed within the at least one cooling passage. A component for a gas turbine engine is also disclosed.

The precipitation hardened martensitic stainless steel is characterized by containing, in percent by weight, 12.25 to 14.25% Cr, 7.5 to 8.5% Ni, 1.0 to 2.5% Mo, 0.05% or less C, 0.2% or less Si, 0.4% or less Mn, 0.03% or less P, 0.005% or less S, 0.008% or less N, 0.90 to 2.25% Al, the balance substantially being Fe, and the total content of Cr and Mo being 14.25 to 16.75%. A turbine moving blade and a steam turbine are manufactured by using this martensitic stainless steel.

A flame resistant shield includes two opposing walls between which are positioned at least: a first insulating layer, the first layer being capable of distributing heat in the plane formed by the first layer and being insulating across its thickness, a second insulating layer, one of the opposing walls which covers the first layer being produced from a refractory antioxidant material or having at least the surface intended to be exposed to flames covered with a material preventing this surface from being oxidized, the other wall being a support.