Abstract: A device and method are provided for evaluating the susceptibility of hot cracking in an additive manufacturing process. A first end of a substrate is interconnected to a base and one of the base and a deposition device is moved in a first direction and the second end of the substrate is pulled. A powder is dispensed at a selected rate and an energy bean having an adjustable power density is direct at the powder to melt the powder to form a material which is deposited as a layer of a material on the substrate. During the deposition process or during the deposition of the material on a subsequent substrate, one or more parameters/conditions are varied to determine the point at which hot cracking occurs during the deposition process.

Abstract: In a process for friction stir welding together pieces of dissimilar material, a first piece of a second metal is overlaid onto a first piece of a first metal that is dissimilar from the second metal such that at least a portion of the first piece of second metal overlaps a portion of the first piece of first metal. The first piece of second metal has a plurality of holes therein and the holes are disposed in overlapping relationship with the portion of the first piece of first metal. Each of the holes is filled with a plug formed from the first metal. The first piece of first metal is friction stir welded to the first piece of second metal at each of the plug locations.

Abstract: In a process for friction stir welding together pieces of dissimilar material, a first piece of a second metal is overlaid onto a first piece of a first metal that is dissimilar from the second metal such that at least a portion of the first piece of second metal overlaps a portion of the first piece of first metal. A second piece of the first metal is placed in side-to-side relationship with the first piece of second metal and overlies another portion of the first piece of first metal. The relative arrangement between the second piece of first metal and the first piece of second metal define a joint line overlying the first piece of first metal. The first piece of first metal, the first piece of second metal, and the second piece of first metal are friction stir welded together along the joint line.

Abstract: In a process for friction stir welding together pieces of dissimilar material, a first piece of a second metal is overlaid onto a first piece of a first metal that is dissimilar from the second metal such that at least a portion of the first piece of second metal overlaps a portion of the first piece of first metal. A second piece of the first metal is placed in side-to-side relationship with the first piece of second metal and overlies another portion of the first piece of first metal. The relative arrangement between the second piece of first metal and the first piece of second metal define a joint line overlying the first piece of first metal. The first piece of first metal, the first piece of second metal, and the second piece of first metal are friction stir welded together along the joint line.

Abstract: Friction stir welding is enhanced by preheating of the workpiece with an electrical arc, such as an arc applied by a common gas-tungsten arc welding (GTAW) torch. As the arc is moved about a path on the workpiece, it preheats or partially welds the path, with the friction stir welding head following along the path to complete the weld.

Abstract: Friction stir welding is enhanced by preheating of the workpiece with an electrical arc, such as an arc applied by a common gas-tungsten arc welding (GTAW) torch. As the arc is moved about a path on the workpiece, it preheats or partially welds the path, with the friction stir welding head following along the path to complete the weld.

Abstract: Crystals of doped semiconductors and alloys are grown in a Czochralski process utilizing a single crucible. An upper heater around the crucible applies heat to an upper portion of the crucible while a lower heater below the upper heater applies heat to a lower portion of the crucible independently of the upper heater. A solid feed material in a lower portion of the crucible is maintained by the lower heater at a temperature below the melting point of the feed material, while the upper heater maintains an upper portion of the crucible at a higher temperature to provide a melt of the feed material in the upper portion of the crucible.

Abstract: Growth of homogeneous single crystals is carried out by a modified Bridgman-type process using a second melt of a different composition to replenish the first melt of a predetermined composition held in the crystal growth container. By controlling the replenishing rate and suppressing diffusion between the two melts, composition variations in the first melt and hence the growing crystal are compensated. The second melt may be maintained at a predetermined higher temperature than the first melt. The first melt may be agitated during crystal growth by rotation. A liquid encapsulant may be used.

Abstract: Growth of monocrystalline rods from a bulk melt is carried out by a modified Czochralski process using a float which floats on the bulk melt held in a crucible. Melt flows through a passageway in the float to a crystal growth zone at a rate which prevents diffusion of dopant from the growth zone to the bulk melt. The shape of the crystal may be determined by a shaper wall in the float which defines the growth zone, in which case the crystal body is pulled from the float as it grows without rotating the crystal. The temperature of the float near the shaper wall may be monitored and controlled to control the crystallization process.

Abstract: Floating zone refining or crystal growth is carried out by providing rapid relative rotation of a feed rod and finish rod while providing heat to the junction between the two rods so that significant forced convection occurs in the melt zone between the two rods. The forced convection distributes heat in the melt zone to allow the rods to be melted through with a much shorter melt zone length than possible utilizing conventional floating zone processes. One of the rods can be rotated with respect to the other, or both rods can be counter-rotated, with typical relative rotational speeds of the rods ranging from 200 revolutions per minute (RPM) to 400 RPM or greater. Zone refining or crystal growth is carried out by traversing the melt zone through the feed rod.

Abstract: An apparatus for growing a monocrystalline body (30) from a polycrystalline feed rod (22) includes a heater (20) that is positioned to heat a short section of the polycrystalline rod (22) to create a molten zone (34). The heater (20) is formed to include a shaper (40) that contacts the polycrystalline rod (22) in the molten zone (34) and has a hole (46) to allow flow in the molten zone (34) between the polycrystalline rod (22) side and the monocrystalline body (30) side of the shaper. The shaper (40) has an edge (42) that defines the boundary of the cross-section of the monocrystalline body (30) that is formed as the molten material solidifies.