Abstract: A method of forming a plug-like member comprises placing a consumable member (4) in a bore (1) of a workpiece (2). The consumable member (4) is rotated relative to the workpiece (2) while they are urged together so as to generate frictional heat and the formation of plasticised material (5). The plasticised material (5) is allowed to solidify so as to form a plug-like member having an outer surface conforming to the inner surface of at least part of the bore (1). The plug-like member is either left in situ or, following formation of the complete plug-like member, removed from the workpiece.

Abstract: A method of operating on a workpiece comprises offering a probe of material harder than the workpiece material to a continuous surface of the workpiece causing relative cyclic movement between the probe and the workpiece while urging the probe and workpiece together whereby frictional heat is generated as the probe enters the workpiece so as to create a plasticized region in the workpiece material around the probe, stopping the relative cyclic movement, and allowing the plasticized material to solidify around the probe. This technique, which we refer to as "friction plunge welding" provides a very simple method of joining a probe to a workpiece. The method can be used for repairing cracks and the like within a workpiece or for joining members, such as studs or bushes, to a workpiece.

Abstract: A method of forming or reforming a composite material comprises relatively rotating a pair of members (2,3) while urging them together under pressure so as to mix or remix together the materials (1) making up the composite. The urging direction is substantially parallel with the axis of relative rotation. The composite is then extruded (7).

Abstract: A method of providing a material, typically a metal, surface on a substrate (1), comprises applying a consumable member (4) to the substrate (1) under pressure. The member (4) and substrate (1) are moved relative to one another along an arcuate path. Heat is generated at the interface between the member and the substrate so that material is laid down on the substrate along the path. The movement of the metal member (4) typically includes one or more cyclic components.