A process for welding a first part and a second part, includes: a linear friction step during which the two parts are rubbed against one another in a linear movement, a first cooling step during which the temperature of the parts thus welded is reduced to ambient temperature, a heating step during which the parts thus welded are heated to a temperature above a temperature of transition between a two-phase - field and a single-phase field of the material constituting the two parts, and a second cooling step during which the temperature of the parts thus heated is reduced to ambient temperature. Such a process makes it possible to transform the structure of the welding zone and of the whole part thus produced into a lamellar structure in a transformed matrix which exhibits better damage tolerance.

A method of operating a linear friction welding system in one embodiment includes establishing a ram vibration amplitude by positioning a stop of a phase change assembly and positioning the phase change assembly in different configurations to establish different phase relationships between two eccentrically engaged power shafts while one of the power shafts is driven by a timing component and the other power shaft is driven by the timing component through the phase change assembly. In one phase change assembly configuration a ram operably connected to one of two components to be welded does not vibrate when the first power shaft and the second power shaft rotate while in another phase change assembly configuration the ram vibrates. Pressure between the two components is controlled to provide scrub pressure when the ram vibrates and forge pressure when the ram is no longer vibrating.

A dissimilar material solid phase bonding method is disclosed wherein one member and another member having different compositions are brought into contact with one another by way of an insert material to form an interface (1) to be bonded, at which the one member and the insert material are in contact with one another, and an interface (2) to be bonded, at which the other member and the insert material are in contact with one another; the temperature of the interface (1) to be bonded and the interface (2) to be bonded is raised by means of frictional heat and/or by electrical heating; a bonding pressure (1) is applied substantially perpendicular to the interface (1) to be bonded; a bonding pressure (2) is applied substantially perpendicular to the interface (2) to be bonded; and the bonding pressure (1) and the bonding pressure (2) are set to different values.

A method for producing an enhanced property integrally bladed rotor includes solution heat treating a stub-containing rotor hub forging; water quenching the solution heat treated stub-containing rotor hub; aging the water quenched stub-containing rotor hub forging; linear friction welding airfoils onto each of a multiple of stubs of the stub-containing rotor hub forging; and concurrently stress relieving the linear friction welds of each of the multiple of stubs within a predefined area while ensuring that a hub inner diameter does not exceed a predetermined temperature.

A method of fabricating a rack, the method includes: supporting a first rack bar having a first toothed part on a shaft of the first rack bar; supporting a second rack bar having a second toothed part on a shaft of the second rack bar such that an axial center line of the second rack bar coincides with an axial center line of the first rack bar; supporting a joint member between the first and second rack bars such that an axial center line of the joint member coincides with the axial center lines of the first and second rack bars; rotating the joint member about the axial center lines of the first and second rack bars relative to the first and second rack bars; and bringing an end of the first rack bar and an end of the second rack bar into friction pressure welding with the joint member.

Disclosed is a method of making an integrally bladed rotor. According to the method, a titanium alloy rotor disk with 15-50% by volume of primary alpha grains with a grain size less than 10 m and secondary alpha grains comprising widmanstatten grains with a grain size less than 1.0 m is subjected to thermal processing. After thermal processing, a blade having an airfoil and a base is positioned such that a base surface is in contact with an outer rim surface of the disk. Heat, pressure, and motion are applied between the blade and the disk to friction weld the base surface to the disk outer rim surface.

A linear friction welding system in one embodiment includes a welding control system operably connected to a hydraulic press and a ram, the welding control system including a processing circuit operably connected to a memory and configured to execute program instructions stored in the memory to bring a shaped charge portion of a first component to be welded into contact with a second component to be welded, and establish an initial scrub load pressure between the two components based upon a ratio between initial surface area of a contact initiation portion of the shaped charge portion and a final surface area of the first component. The processing circuit increases pressure between the components from the initial scrub load pressure to a target scrub load pressure before terminating oscillation of the ram and establishing or maintaining a weld load pressure.

A linear friction welding system in one embodiment includes a ram configured to oscillate along a welding axis, and a first and second power shaft operably connectable to the ram through a vibrating assembly. Respective motors are configured to drive respective power timing gears fixedly connected to the first and second power shafts. A slave timing gear is operably connected to the first power shaft in variable rotational relationship and to the second power shaft in fixed rotational relationship. The first slave timing gear is configured to be driven by one power shaft to force oscillation of the ram and by the other power shaft to stop oscillation of the ram.

A method for joining materials using additive friction stir techniques is provided. The method joins a material to a substrate, especially where the material to be joined and the substrate are dissimilar metals. One such method comprises (a) providing a substrate with one or more grooves; (b) rotating and translating an additive friction-stir tool relative to the substrate; (c) feeding a filler material through the additive friction-stir tool; and (d) depositing the filler material into the one or more grooves of the substrate. Translation and rotation of the tool causes heating and plastic deformation of the filler material, which flows into the grooves of the substrate resulting in an interlocking bond between the substrate and filler material. In embodiments, the depositing of the filler material causes deformation of the grooves in the substrate and an interlocking configuration between the grooves of the substrate and the filler material results.

A method of operating a linear friction welding system in one embodiment includes positioning a phase change assembly driven by a motor in different configurations to establish different phase relationships between two eccentrically engaged power shafts while one of the power shafts is driven by the motor and the other power shaft is driven by the phase change assembly. In one phase change assembly configuration a ram operably connected to one of two components to be welded does not vibrate when the first power shaft and the second power shaft rotate while in another phase change assembly configuration the ram vibrates. Pressure between the two components is controlled to provide scrub pressure when the ram vibrates and forge pressure when the ram is no longer vibrating.