Abstract: A control system for active stability management of a compressor element of a turbine engine is provided. In one example aspect, the control system includes one or more computing devices configured to receive data indicative of an operating characteristic associated with the compressor element. For instance, the data can be received from a high frequency sensor operable to sense pressure at the compressor element. The computing devices are also configured to determine, by a machine-learned model, a stall margin remaining of the compressor element based at least in part on the received data. The machine-learned model is trained to recognize certain characteristics of the received data and associate the characteristics with a stall margin remaining of the compressor element. The computing devices are also configured to cause adjustment of one or more engine systems based at least in part on the determined stall margin remaining.

Abstract: Methods of forming sintered coatings are provided, along with the resulting coatings on a substrate. The sintered coating may comprise a rare earth compound and a sintering aid, with the rare earth compound has the formula: A1?bBbZ1?dDdMO6 where A is Al, Ga, In, Sc, Y, Ce, Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu, Fe, Cr, Co, Mn, Bi, or a mixture thereof; b is 0 to about 0.5; Z is Hf, Ti, or a mixture thereof; D is Zr, Ce, Ge, Si, or a mixture thereof; d is 0 to about 0.5; and M is Ta, Nb, or a mixture thereof. The coating may be densified at a sintering temperature, such as 1300° C. to 1600° C.

Abstract: An intermediate investment casting mold includes at least a shell and a core. The shell has an outer surface and an inner surface, with the inner surface defining an interior for the shell. The core is located in the interior of the shell and is at least partially spaced from the inner surface of the shell. A void can be defined as the space between the core and the inner surface. The intermediate investment casting mold can include a plurality of anchors.

Abstract: Methods for forming a coating on a surface of a substrate are provided. The method can include: preheating the surface of the substrate; spraying a slurry suspension onto the surface of the substrate to form a coating, wherein the slurry composition comprises a rare earth compound, a sintering agent, and a solvent, wherein the rare earth compound has the formula: A1-bBbZ1-dDdMO6 where A is Al, Ga, In, Sc, Y, Ce, Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu, Fe, Cr, Co, Mn, Bi, or a mixture thereof; b is 0 to 0.5; Z is Hf, Ti, or a mixture thereof; D is Zr, Ce, Ge, Si, or a mixture thereof; d is 0 to 0.5; and M is Ta, Nb, or a mixture thereof; and thereafter, heat treating the coating to densify the coating from an initial porosity to a sintered porosity.

Abstract: Methods of forming sintered coatings are provided, along with the resulting coatings on a substrate. The sintered coating may comprise a rare earth compound and a sintering aid, with the rare earth compound has the formula: A1?bBbZ1?dDdMO6 where A is Al, Ga, In, Sc, Y, Ce, Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu, Fe, Cr, Co, Mn, Bi, or a mixture thereof; b is 0 to about 0.5; Z is Hf, Ti, or a mixture thereof; D is Zr, Ce, Ge, Si, or a mixture thereof; d is 0 to about 0.5; and M is Ta, Nb, or a mixture thereof. The coating may be densified at a sintering temperature, such as 1300° C. to 1600° C.

Abstract: A control system for active stability management of a compressor element of a turbine engine is provided. In one example aspect, the control system includes one or more computing devices configured to receive data indicative of an operating characteristic associated with the compressor element. For instance, the data can be received from a high frequency sensor operable to sense pressure at the compressor element. The computing devices are also configured to determine, by a machine-learned model, a stall margin remaining of the compressor element based at least in part on the received data. The machine-learned model is trained to recognize certain characteristics of the received data and associate the characteristics with a stall margin remaining of the compressor element. The computing devices are also configured to cause adjustment of one or more engine systems based at least in part on the determined stall margin remaining.