The present invention relates to tooling and methods for disposing, coating, building up, repairing, or otherwise modifying the surface of a metal substrate using frictional heating and compressive loading of a consumable metal material against the substrate. Embodiments of the invention include friction-based fabrication tooling comprising a non-consumable member with a throat and a consumable member disposed in the throat, wherein the throat is operably configured such that during rotation of the non-consumable member at a selected speed, the throat exerts normal forces on and rotates the consumable member at the selected speed; and comprising means for dispensing the consumable member through the throat and onto a substrate using frictional heating and compressive loading. Embodiments of the invention also include fabrication methods using the tools described herein.

Disclosed is a method for making polystyrene foam which utilizes one or more atmospheric gases, particularly CO.sub.2, as the blowing agent in combination with a polymer processing aid (PPA), typically an ester that is relatively non-volatile at the extrusion temperature range. The blowing agent and the PPA may both be introduced into the molten thermoplastic polystyrene resin or the PPA may be incorporated in the solid source polystyrene resins. The resulting foam will be substantially free of residual blowing agent and dimensionally stable at ambient temperatures.

Disclosed is a method for making polystyrene foam which utilizes one or more atmospheric gases, particularly CO.sub.2, as the blowing agent in combination with a polymer processing aid (PPA), typically an ester that is relatively non-volatile at the extrusion temperature range. The blowing agent and the PPA may both be introduced into the molten thermoplastic polystyrene resin or the PPA may be incorporated in the solid source polystyrene resins. The resulting foam will be substantially free of residual blowing agent and dimensionally stable at ambient temperatures.

A piston for an internal combustion engine may include a substantially circular body composed of an aluminum containing base material defining a top portion having at least one cavity. At least one coating layer may be disposed on at least one area defined by at least one of the top portion and the at least one cavity. The at least one coating layer may include at least one chemical compound derived from a chemical reaction between the base material of the body and the at least one coating layer in response to friction generated by a dragging movement of a non-consumable rotary pin with the at least one coating layer.

The present invention provides a method of manufacturing composite material, comprising the steps of: coating a thermally conductive composition on a surface portion of a metal material in at least one configuration from among a paste, film, and tape; and friction stirring the metal material, coated with the thermally conductive composition, at least once, and reacting at least a part of the surface portion of the metal material with the thermally conductive composition to form a composite material.

Provided is an electrical steel strip friction stir welding method that is able to inhibit the occurrence of coil joint fractures on a production line caused by deterioration of mechanical properties and shape of the coil joint while maintaining high work efficiency and that is also advantageous in terms of rotating tool durability. In the method, preheated double-sided friction stir welding is performed, diameter D (mm) of shoulders of rotating tools satisfies the relationship of the following Expression (7), and rotation speed RS (r/min) of the rotating tools, the diameter D (mm) of shoulders of the rotating tools, and joining speed JS (mm/min), expressed as RSD.sup.3/JS, satisfy the relationship of the following Expression (8), 4TJD10TJ . . . (7), and 180TJRSD.sup.3/JS1500TJ . . . (8).

Intended is to improve the corrosion resistance of an overlay used in a nuclear power plant, and to reduce dissolution of cobalt from an overlay. The corrosion and wear resistant overlay 7 is formed along a surface of a base 2 by laser lamination modeling, and is configured from a plurality of metal layers 1a, 1b, 1c, and 1d of a Co-base alloy. The thickness of carbide eutectics that precipitate in the metal layers 1a, 1b, 1c, and 1d is the largest in the metal layer 1a closest to the base 2, and is gradually smaller in the metal layers 1b, 1c, and 1d farther away from the base 2. The intensity of the laser beam applied to form layers by laser lamination modeling is adjusted so that the carbide eutectics that precipitate in at least the outermost metal layer 1d have a controlled size of 10 m or less.

An electrical steel strip friction stir welding method is provided that is able to inhibit the occurrence of coil joint fracture on a production line caused by degradation of mechanical properties and shape of the coil joint, under high work efficiency conditions. Double-sided friction stir welding with post-cooling is carried out under conditions that simultaneously satisfy the relationships of Expressions (1) and (2).