Abstract: A grit blasting and alkaline etch surface pretreatment that is applied to a metallic airfoil. The metallic airfoil includes pockets or cavities that have been fabricated into the airfoil to reduce the weight of the airfoil. The pretreatment includes grit blasting the surface of the pockets or cavities, followed by washing the airfoil and treating the airfoil in an alkaline etch bath. After any remaining solution from the bath is neutralized and within twenty-four hours of the end of the pretreatment, primer is applied to the surface of the pockets or cavities. After the primer is applied to the surface of the pockets, a lightweight resin is injected into the pockets and bonds to the primer forming a mechanical bond with good fracture toughness at elevated temperatures.

Abstract: A fan blade includes a metal airfoil having a pocket disposed in a first side thereof, with the pocket including a filler bonded thereto. The pocket includes a plurality of cells separated by corresponding ribs which are submerged in the filler.

Abstract: A steam turbine blade, such as those used in an electric power generation steam turbine, has an airfoil portion. The airfoil portion includes a metallic section consisting essentially of metal and at least one (lightweight) panel section not consisting essentially of metal. The metallic section extends from generally the blade root to generally the blade tip. Each panel section is an elastomeric section. The metallic section and the at-least-one panel section only together define a generally airfoil shape.

Abstract: A lightweight, impact-resistant gas turbine blade, such as an aircraft engine fan blade, has an airfoil portion. The airfoil portion includes a metallic section consisting essentially of metal and at least one panel section not consisting essentially of metal. The metallic section extends from generally the blade root to generally the blade tip. Each panel section is an elastomeric section. Preferably, the metallic section and the at-least-one panel section only together define a generally airfoil shape.

Abstract: A lightweight, impact-resistant gas turbine blade, such as an aircraft engine fan blade, has an airfoil portion which includes a metal section and at least one foam section which together define a generally airfoil shape. The metal section extends from generally the blade root to generally the blade tip. A composite skin generally completely surrounds, and is bonded to, the metal section and the at-least-one foam section. Preferably, an erosion coating generally completely surrounds, and is bonded to, the composite skin.