FZ single crystals are pulled by melting a polycrystal with electromagnetic melting apparatus and then recrystallizing. First, a lower end of the polycrystal is melted; second, a monocrystalline seed is attached to the lower end of the polycrystal and melted beginning from an upper end thereof; third, between a lower section of the seed and the polycrystal, a thin neck is formed whose diameter (d.sub.D) is smaller than that (d.sub.I) of the seed; and fourth, between the thin neck section and the polycrystal, a conical section is formed. Before the conical growth, a switchover position (h′) of the polycrystal, the position at which the rate of polycrystal movement relative to the melting apparatus is to be reduced is determined, and the rate is reduced, in amount when the switchover position (h′) is reached.

FZ single crystals are pulled by melting a polycrystal with electromagnetic melting apparatus and then recrystallizing. First, a lower end of the polycrystal is melted; second, a monocrystalline seed is attached to the lower end of the polycrystal and melted beginning from an upper end thereof; third, between a lower section of the seed and the polycrystal, a thin neck is formed whose diameter (d.sub.D) is smaller than that (d.sub.I) of the seed; and fourth, between the thin neck section and the polycrystal, a conical section is formed. Before the conical growth, a switchover position (h′) of the polycrystal, the position at which the rate of polycrystal movement relative to the melting apparatus is to be reduced is determined, and the rate is reduced, in amount when the switchover position (h′) is reached.

Disclosed is a method of preparing single crystal ingot of barium zirconium oxide. The method includes preparing a cylindrical BaZrO.sub.3 ceramic by pulverizing a BaZrO.sub.3 compound into a powder and sintering the same into a cylindrical ceramic form, ii) fixing two cylindrical BaZrO.sub.3 ceramics to an optical floating zone furnace, joining the two cylindrical BaZrO.sub.3 ceramics together and melting the junction at a temperature of 2,600 to 3,500 C. using light emitted from a xenon lamp or laser, and after the melting, moving the two cylindrical BaZrO.sub.3 ceramics in a direction parallel to an axis of rotation thereof, enabling the molten junction to be solidified, and thereby growing a single crystal.

Some variations provide a method of making an additively manufactured single-crystal metallic component, comprising: providing a feedstock comprising a first metal or metal alloy; providing a build plate comprising a single crystal of a second metal or metal alloy; exposing the feedstock to an energy source for melting the feedstock, generating a melt layer on the build plate; and solidifying the melt layer, generating a solid layer (on the build plate) of a metal component. The solid layer is also a single crystal of the first metal or metal alloy. The method may be repeated many times to build the part. Some variations provide a single-crystal metallic component comprising a plurality of solid layers in an additive-manufacturing build direction, wherein the plurality of solid layers forms a single crystal of a metal or metal alloy with a continuous crystallographic texture. The crystal orientation may vary along the additive-manufacturing build direction.

Some variations provide a method of making an additively manufactured single-crystal metallic component, comprising: providing a feedstock comprising a first metal or metal alloy; providing a build plate comprising a single crystal of a second metal or metal alloy; exposing the feedstock to an energy source for melting the feedstock, generating a melt layer on the build plate; and solidifying the melt layer, generating a solid layer (on the build plate) of a metal component. The solid layer is also a single crystal of the first metal or metal alloy. The method may be repeated many times to build the part. Some variations provide a single-crystal metallic component comprising a plurality of solid layers in an additive-manufacturing build direction, wherein the plurality of solid layers forms a single crystal of a metal or metal alloy with a continuous crystallographic texture. The crystal orientation may vary along the additive-manufacturing build direction.

Scanning Laser Epitaxy (SLE) is a layer-by-layer additive manufacturing process that allows for the fabrication of three-dimensional objects with specified microstructure through the controlled melting and re-solidification of a metal powders placed atop a base substrate. SLE can be used to repair single crystal (SX) turbine airfoils, for example, as well as the manufacture functionally graded turbine components. The SLE process is capable of creating equiaxed, directionally solidified, and SX structures. Real-time feedback control schemes based upon an offline model can be used both to create specified defect free microstructures and to improve the repeatability of the process. Control schemes can be used based upon temperature data feedback provided at high frame rate by a thermal imaging camera as well as a melt-pool viewing video microscope. A real-time control scheme can deliver the capability of creating engine ready net shape turbine components from raw powder material.

Scanning Laser Epitaxy (SLE) is a layer-by-layer additive manufacturing process that allows for the fabrication of three-dimensional objects with specified microstructure through the controlled melting and re-solidification of a metal powders placed atop a base substrate. SLE can be used to repair single crystal (SX) turbine airfoils, for example, as well as the manufacture functionally graded turbine components. The SLE process is capable of creating equiaxed, directionally solidified, and SX structures. Real-time feedback control schemes based upon an offline model can be used both to create specified defect free microstructures and to improve the repeatability of the process. Control schemes can be used based upon temperature data feedback provided at high frame rate by a thermal imaging camera as well as a melt-pool viewing video microscope. A real-time control scheme can deliver the capability of creating engine ready net shape turbine components from raw powder material.

A method of method of forming or repairing a superalloy article having a columnar or equiaxed or directionally solidified or amorphous or single crystal microstructure includes emitting a plurality of laser beams from selected fibers of a diode laser fiber array corresponding to a pattern of a layer of the article onto a powder bed of the superalloy to form a melt pool; and controlling a temperature gradient and a solidification velocity of the melt pool to form the columnar or single crystal microstructure.

A method of method of forming or repairing a superalloy article having a columnar or equiaxed or directionally solidified or amorphous or single crystal microstructure includes emitting a plurality of laser beams from selected fibers of a diode laser fiber array corresponding to a pattern of a layer of the article onto a powder bed of the superalloy to form a melt pool; and controlling a temperature gradient and a solidification velocity of the melt pool to form the columnar or single crystal microstructure.

A method of additive manufacturing a structure on a pre-existing includes disposing the pre-existing component in a bed of powdery base material and levelling the component, such that a manufacturing plane of the component can be recoated with the base material and alternatingly recoating and irradiating the manufacturing plane with an energy beam in order to additively build up the structure, wherein the irradiation is carried out in that the manufacturing plane is scanned by the beam in a non-continuous way, wherein, for the irradiation according to a second vector for the structure, the beam is either only guided parallel with respect to a previous first vector, or the irradiation process is paused after the irradiation of the first vector for a time span between 1/10 second to 2 seconds until the irradiation is continued with the second vector.