Abstract: A method of making a hollow article, for example, a hollow airfoil, from first and second preformed sections involves a first precursor (seal) bonding step where a low external pressure and internal vacuum are utilized to form a substantially gas impermeable seal bond between opposing bonding surfaces of the sections with only limited distortion of one of the sections and no distortion of the other section, a diffusion bonding step where a high external and high internal pressure is utilized to form a complete parent metal diffusion bond between the bonding surfaces without distortion of either section and an inflation step where a high external and high internal pressure are utilized to remove the limited distortion from the affected section without distortion of the unaffected section. The inflation step and diffusion bonding step can be combined into one operation to provide a two step method of making the hollow article.

Abstract: A method for making a hollow article, for example, a hollow airfoil, from first and second preformed sections involves first forming a precursor fluid impermeable (seal) diffusion bond between opposing bonding surfaces. The precursor bond is formed by subjecting the assembled sections to coordinated pressure-time-temperature conditions where a first high external pressure is applied to reduce any gaps between the opposing bonding surfaces and then a second lower external pressure is applied to actually form the precursor diffusion bond with only limited distortion of one of the sections and no distortion of the other section. In a second step of the method, the precursor bonded sections are subjected to coordinated pressure-time-temperature conditions where a high external and high internal pressure are utilized to form a complete patent metal diffusion bond between the bonding surfaces without distortion of either section.

Abstract: An electrode or cathode assembly includes at least one electrode moveable relatively toward a workpart such as a turbine blade. The electrode includes a primary work face for machining the airfoil portion of the turbine blade. The electrode further includes secondary workfaces transverse to the primary workface for machining the shroud portion and the platform portion of the turbine blade which extend at negative angles transverses to the airfoil portion of the turbine blade. The primary workface comprises upper and lower electrode portions each having a plurality of fingers. The fingers of the upper electrode portion are alternatively disposed among the fingers of the lower electrode portion such that the opposing fingers interleave side by side with one another when the primary workface is closed.

Abstract: A method of joining titanium to a dissimilar metal wherein a predetermined amount of heat and pressure is applied sufficient to plastically deform only one of the metals being joined. The heat and pressure combine to flow one metal into shaped surfaces existing in the second metal, maintain the joint in compression through differrential thermal expansion and bonding the deformed metal to the other metal. The method uses a temperature sufficiently low to effect bonding without any chance for the formation of excessive brittle intermetallic phases.

Abstract: An improved inspection method determines how closely the cross sectional configuration of an airfoil corresponds to a reference cross sectional configuration. When an airfoil is to be inspected, the airfoil is measured and the mean camber line is determined. The mean camber lines of the reference and measured airfoils are shifted relative to each other through a plurality of relationships. A best fit relationship is determined in which the measured and reference airfoils overlie each other to a maximum extent possible. The best fit relationship can be determined by comparing points on the major side surfaces of the measured and reference airfoils. Alternatively, the best fit relationship can be determined by comparing points on the mean camber lines of the measured and reference airfoils.