Abstract: A multimetallic article of manufacture comprising a body (40) of a first metallic material with discrete regions (65) therein of a second metallic material is manufactured by the in situ alloying of a third material with the first material. The alloying is performed by depositing the third material at locations on the body where the first material is melted by an energy beam (45) such as a carbon dioxide laser or electron beam.

Abstract: Laser welding is accomplished in a laser welding arrangement by positioning a plurality of workpieces to be joined next to one another so as to form an assembly having at least one interface between the workpieces, by simultaneously directing two laser beams from opposite sides of the assembly against effective welding regions of the workpieces that adjoin the interface and are substantially aligned with one another across the interface, and by effecting relative movement between the assembly and the two laser beams along the interface while maintaining the substantial alignment of the effective welding regions.

Abstract: A novel multiple spot laser welding apparatus includes a bendable mirror capable of deformation, which receives a laser beam at a single reflective surface thereof. A deformation device deforms the single reflective surface of the bendable mirror to provide a plurality of laser sub-beams to a workpiece, generating laser spots on surfaces thereof. The apparatus can be used in a laser welding method that provides a common weld pool formed by laser spots transverse to the weld seam. Another laser welding method provides multiple laser spots oriented along a weld seam producing a common weld pool therebetween. Still another laser welding method provides multiple laser spots along a weld seam producing distinct weld pools.

Abstract: A mechanical scanning apparatus adapted for oscillating the focus zone of a beam of radiation having high power to modify and control the nature and extent of the interaction zone on a workpiece is disclosed. The apparatus includes a compound beam adapted for being vibrated in a vibratory mode resulting in oscillatory motion of at least a first end of the compound beam; a reflective surface attached to the first end of the compound beam and adapted for focussing radiation incident thereon to a focus zone, and means for vibrating the compound beam to induce oscillatory motion of the reflective surface resulting in oscillatory motion of the focus zone. For vibration frequencies greater than the characteristic thermal response time of the workpiece material, the effect is a broadening of the interaction zone with a beam-material interaction characteristic of a reduced incident average power intensity while maintaining a high local intensity essential to the establishment of effective radiation-material coupling.

Abstract: A mechanical scanning apparatus adapted for oscillating the focus zone of a beam of radiation having high power to modify and control the nature and extent of the interaction zone on a workpiece is disclosed. The apparatus includes a compound beam adapted for being vibrated in a vibratory mode resulting in oscillatory motion of at least a first end of the compound beam; a reflective surface attached to the first end of the compound beam and adapted for focussing radiation incident thereon to a focus zone, and means for vibrating the compound beam to induce oscillatory motion of the reflective surface resulting in oscillatory motion of the focus zone. For vibration frequencies greater than the characteristic thermal response time of the workpiece material, the effect is a broadening of the interaction zone with a beam-material interaction characteristic of a reduced incident average power intensity while maintaining a high local intensity essential to the establishment of effective radiation-material coupling.

Abstract: An apparatus for welding T-frame stiffeners circumferentially to the interior surface of a cylindrical shell at selected axial positions to fabricate reinforced hull sections suitable for boat construction is disclosed. The apparatus is adapted for providing simultaneous two-sided Tee welds of the T-frame to the shell using radiation from a laser source to form quickly the welds which significantly reduces the time and costs of fabricating hull subassemblies.

Abstract: A method of material processing, in particular welding, utilizing high frequency interruption of a continuous wave beam of radiation is disclosed. The pulses of laser radiation are generated at a pulse repetition rate more rapid than the thermal response time of the material, typically greater than one kilohertz, wherein the material reacts with the pulses such that the characteristics of the surface reflectivity of the material are dominated by the peak power in the pulse and the characteristics of the melting of the material are controlled by the average power of the pulses. The duration of each pulse is controlled to be less than the time required to generate a beam absorbing plasma adjacent the weld zone. The absence of beam absorbing plasma and the efficient destruction of the reflectivity of the surface of the material results in increased welding efficiency and/or increased welding speed.

Abstract: A welding device capable of providing a blanket of nonreactive gas to isolate atmospheric gases from a weld zone to prevent weld contamination and capable of providing a stream of suppression gas across the path of a welding beam to suppress the formation of a beam absorbing plasma is disclosed. The device comprises a housing having a welding beam entrance port, a structure wall cooperating with the housing to form a first cavity therein and having an exit port aligned with the entrance port, means for supplying suppression gas to the first cavity, means for exhausting the suppression gas from the first cavity, a base cooperating with the housing and the structure wall to form a second cavity within the housing, means for providing a nonreactive gas to the second cavity, and means for passing the nonreactive gas from the second cavity to the weld zone.

Abstract: Gas delivery means for providing a flow of gas to the kerf in a workpiece which is being cut by a beam of laser radiation is disclosed. The distribution means consists of a thin wafer which is placed in the path of the cutting beam adjacent to the workpiece and a stream of gas directed along the axis of laser propagation blows the kerf clean. An upper gas port and a lower gas port allow the laser radiation to pass through the wafer without any transmissive optics. Use of the gas delivery means with various gases at high pressure and with laser beams at power levels which were previously impractical are discussed.

Abstract: A method of cutting a multilayer pile of sheet material with a beam of laser radiation is disclosed. A laser beam having a low order mode intensity distribution is focused onto the pile and during cutting a stream of liquid coolant is directed into the material vaporization region to absorb energy from the outer region of the mode distribution which could otherwise result in adhesion of adjacent layers, globularization, singeing or other undesired effect.

Abstract: A method of accomplishing a controlled weld with a beam of laser radiation is disclosed. The workpiece is cleaned and fitted prior to joining and a flow of a gas is provided in the weld region to prevent the formation of radiation insulating plasma between the laser source and the workpiece and to aspirate gaseous impurities from the weld zone. In addition, a trailing cover gas is provided to both the top and the bottom of the weld until the joint is sufficiently cooled to prevent reaction between the metal and the atmosphere. The beam must contain more than two kilowatts of power and be focusable on the workpiece to a power density of at least one megawatt per square inch in order to produce a keyhole in the fusion zone. Further, a weld speed in excess of twenty inches per minute and a progressive solidification technique of the weld contribute to the expulsion of contaminants from the weld.