Embodiments of the invention are directed to compact bearing assemblies configured to operate in small spaces and/or in harsh environments, bearing apparatuses including such bearing assemblies, and method of operating such bearing assemblies and apparatuses. For instance, one or more compact bearing assemblies may at least partially rotatably secure a shaft of a power generation unit to a housing thereof. Also, a first compact bearing assembly may connect or couple to the shaft and may rotatably engage a second compact bearing assembly, which may be connected or otherwise secured to the housing.

A nanocrystalline bainitic steel consisting of, by weight percentage: 0.3% to 0.6% carbon; 9.0% to 20.0% nickel; up to 10% cobalt; 1.0% to 4.5% aluminium; up to 0.5% molybdenum; up to 0.5% manganese; up to 0.5% tungsten; up to 3.0% chromium; and the balance being iron and impurities.

Disclosed herein is a method of manufacturing a double walled section of an aerofoil (701) of a gas turbine engine (10), the method comprising: forming a plurality of columns (402) on an outer surface of a first structure; forming a plurality of columns (402) on a surface of each of a plurality of parts of a second structure; and forming a double walled section of an aerofoil (701) by attaching the ends of columns (402) on each part of the second structure to the ends of columns (402) on the first structure such that the first structure is an inner wall (401) of the section of the aerofoil (701) and the second structure is an outer wall (501) of the section of the aerofoil (701).

An article includes a body that has a first section and a second section bonded with the first section. The first section is formed with a first material that has a first microstructure and the second section is formed of a second material that has a second, different microstructure.

A rotary-mechanical device, capable of extracting energy from a fluid flow and converting it into rotational motion, may comprise a turbine rotor. This turbine rotor may have an exterior surface extending between two opposing sides. The exterior surface may be formed of a plurality of straight lines, each spanning from a first edge, bordering one of the sides, to a second edge, bordering the opposite side. Each of the straight lines may be disposed in an individual plane running perpendicular to a rotational axis of the turbine rotor, wherein the rotational axis is positioned equidistant between the two sides. A turbine rotor of this type may be formed from a unitary mass by degrading the mass with a wire that may be translated and rotated relative to the mass during degradation.

A method for casting comprising: providing a seed, the seed characterized by: an arcuate form and a crystalline orientation progressively varying along an arc of the form; providing molten material; and cooling and solidifying the molten material so that a crystalline structure of the seed propagates into the solidifying material.

An airfoil includes an airfoil body that extends at least between leading and trailing edges, first and second sides, and radially inner and outer ends. The airfoil body includes an aluminum alloy that has a controlled crystallographic texture with respect to a predefined three-dimensional coordinate system. The airfoil can be used in the fan of a gas turbine engine.

Embodiments of the invention are directed to compact bearing assemblies configured to operate in small spaces and/or in harsh environments, bearing apparatuses including such bearing assemblies, and method of operating such bearing assemblies and apparatuses. For instance, one or more compact bearing assemblies may at least partially rotatably secure a shaft of a power generation unit to a housing thereof. Also, a first compact bearing assembly may connect or couple to the shaft and may rotatably engage a second compact bearing assembly, which may be connected or otherwise secured to the housing.

A casting method includes forming a seed. The seed has a first end and a second end and an inner diameter (ID) surface and an outer diameter (OD) surface. The seed second end is placed in contact or spaced facing relation with a chill plate. The first end is contacted with molten material. The molten material is cooled and solidified so that a crystalline structure of the seed propagates into the solidifying material. At least a portion of the seed contacted with the molten material has a solidus higher than a solidus of at least an initial pour portion of the molten material.

An article includes a body that has a coating thereon. The coating has a first portion disposed on a first section of the body and a second portion disposed on a second, different section of the body. The first portion has a first microstructure and the second portion has a second, different microstructure.