Abstract: An engine component is generally provided for a gas turbine engine generating hot combustion gas flow. In one embodiment, the engine the engine component includes a substrate having a hot surface facing the hot combustion gas flow and a cooling surface facing a cooling fluid flow. The substrate defines a film hole extending through the substrate and having an inlet provided on the cooling surface, an outlet provided on the hot surface, and a passage connecting the inlet and the outlet. The passage defines a diffusion section having a pair of side passage walls extending to the outlet on the hot surface, with each of the side passage walls within the diffusion section having a surface roughness (Ra) of about 4 mils to about 7 mils. Methods are also provided for forming a film hole in a CMC substrate.

Abstract: An engine component is generally provided for a gas turbine engine generating hot combustion gas flow. In one embodiment, the engine the engine component includes a substrate having a hot surface facing the hot combustion gas flow and a cooling surface facing a cooling fluid flow. The substrate defines a film hole extending through the substrate and having an inlet provided on the cooling surface, an outlet provided on the hot surface, and a passage connecting the inlet and the outlet. The passage defines a diffusion section having a pair of side passage walls extending to the outlet on the hot surface, with each of the side passage walls within the diffusion section having a surface roughness (Ra) of about 4 mils to about 7 mils. Methods are also provided for forming a film hole in a CMC substrate.

Abstract: A process is provided for forming shaped air holes, such as for use in turbine blades. Aspects of the disclosure relate to forming shaped portions of air holes using a short pulse laser, forming a metered hole corresponding to each shaped portion, and separately finishing the shaped portion using a short-pulse laser. In other embodiments, the order of these operations may be varied, such as to form the shaped portions and to finish the shaped portions using the short-pulse laser prior to forming the corresponding metered holes.

Abstract: A system for producing at least one trench to improve film cooling in a sample is provided. The system includes at least one laser source outputting at least one pulsed laser beam. The pulsed laser beam includes a pulse duration including a range less than about 50 ?s, an energy per pulse having a range less than about 0.1 Joule, and a repetition rate with a range greater than about 1000 Hz. The system also includes a control subsystem coupled to the laser source, the control subsystem configured to synchronize a position of the sample with the pulse duration and energy level in order to selectively remove at least one of a thermal barrier coating, a bondcoat and a substrate metal in the sample to form the at least one trench.

Abstract: A process and system are provided for forming shaped air holes, such as for use in turbine blades. Aspects of the disclosure relate to forming shaped portions of air holes using a short pulse laser, forming a metered hole corresponding to each shaped portion, and separately finishing the shaped portion using a short-pulse laser. In other embodiments, the order of these operations may be varied, such as to form the shaped portions and to finish the shaped portions using the short-pulse laser prior to forming the corresponding metered holes.

Abstract: A system for producing at least one trench to improve film cooling in a sample is provided. The system includes at least one laser source outputting at least one pulsed laser beam. The pulsed laser beam includes a pulse duration including a range less than about 50 ?s, an energy per pulse having a range less than about 0.1 Joule, and a repetition rate with a range greater than about 1000 Hz. The system also includes a control subsystem coupled to the laser source, the control subsystem configured to synchronize a position of the sample with the pulse duration and energy level in order to selectively remove at least one of a thermal barrier coating, a bondcoat and a substrate metal in the sample to form the at least one trench.

Abstract: A thermal barrier coating for an underlying metal substrate of articles that operate at, or are exposed to, high temperatures, as well as being exposed to environmental contaminant compositions. This coating comprises an inner layer nearest to the underlying metal substrate comprising a ceramic thermal barrier coating material having a melting point of at least about 2000° F. (1093° C.), as well as a thermally glazed outer layer having an exposed surface and a thickness up to 0.4 mils (about 10 microns) and sufficient to at least partially protect the thermal barrier coating against environmental contaminants that become deposited on the exposed surface, and comprising a thermally glazeable coating material having a melting point of at least about 2000° F. (1093° C.) in an amount up to 100%. This coating can be used to provide a thermally protected article having a metal substrate and optionally a bond coated layer adjacent to and overlaying the metal substrate.

Abstract: A thermal barrier coating for an underlying metal substrate of articles that operate at, or are exposed to, high temperatures, as well as being exposed to environmental contaminant compositions. This coating comprises an inner layer nearest to the underlying metal substrate comprising a ceramic thermal barrier coating material having a melting point of at least about 2000° F. (1093° C.), as well as a thermally glazed outer layer having an exposed surface and a thickness up to 0.4 mils (about 10 microns) and sufficient to at least partially protect the thermal barrier coating against environmental contaminants that become deposited on the exposed surface, and comprising a thermally glazeable coating material having a melting point of at least about 2000° F. (1093° C.) in an amount up to 100%. This coating can be used to provide a thermally protected article having a metal substrate and optionally a bond coated layer adjacent to and overlaying the metal substrate.

Abstract: A method for producing apertures in hot section components of gas turbine engines made from ceramic matrix composites that have at least one oxidizable component. The method involves forming the apertures using a laser beam controlled by parameters that ablate the ceramic matrix composite in the path of the beam, while simultaneously heating the matrix material, SiC or SiN, to a sufficient temperature to oxidize it to form a silica. Sufficient heat is supplied by the beam to melt the silica to cause it to flow. The melted silica is quickly solidified as recast silica along the walls of the newly created aperture before it has an opportunity to flow and form undesirable geometries. The wall of the aperture is formed of recast silica that is a smooth surface and that forms an oxidation barrier to inhibit any further oxidation of the underlying composite as it is exposed to the high temperatures and oxidative, corrosive atmosphere of an operating gas turbine.

Abstract: A method for producing apertures in hot section components of gas turbine engines made from ceramic matrix composites that have at least one oxidizable component. The method involves forming the apertures using a laser beam controlled by parameters that ablate the ceramic matrix composite in the path of the beam, while simultaneously heating the matrix material, SiC or SiN, to a sufficient temperature to oxidize it to form a silica. Sufficient heat is supplied by the beam to melt the silica to cause it to flow. The melted silica is quickly solidified as recast silica along the walls of the newly created aperture before it has an opportunity to flow and form undesirable geometries. The wall of the aperture is formed of recast silica that is a smooth surface and that forms an oxidation barrier to inhibit any further oxidation of the underlying composite as it is exposed to the high temperatures and oxidative, corrosive atmosphere of an operating gas turbine.

Abstract: A method for producing apertures in hot section components of gas turbine engines made from ceramic matrix composites that have at least one oxidizable component. The method involves forming the apertures using a laser beam controlled by parameters that ablate the ceramic matrix composite in the path of the beam, while simultaneously heating the matrix material, SiC or SiN, to a sufficient temperature to oxidize it to form a silica. Sufficient heat is supplied by the beam to melt the silica to cause it to flow. The melted silica is quickly solidified as recast silica along the walls of the newly created aperture before it has an opportunity to flow and form undesirable geometries. The wall of the aperture is formed of recast silica that is a smooth surface and that forms an oxidation barrier to inhibit any further oxidation of the underlying composite as it is exposed to the high temperatures and oxidative, corrosive atmosphere of an operating gas turbine.