A method of producing a microstructure of a high-alloy steel includes heating the metal stock to a temperature between 1270° C. and 1280° C., at a rate between 40° C./s and 45° C./s, followed by compression applied to the metal stock in a thixotropic process, after which the stock is cooled to ambient temperature. A microstructure is also shown, which includes undissolved metal carbides in the form of globular particles of austenite microstructure and of martensite microstructure.

Embodiments described herein relate generally to systems and methods for using nanocrystalline metal alloy particles or powders to create nanocrystalline and/or microcrystalline metal alloy articles using additive manufacturing. In some embodiments, a manufacturing method for creating articles includes disposing a plurality of nanocrystalline particles and selectively binding the particles together to form the article. In some embodiments, the nanocrystalline particles can be sintered to bind the particles together. In some embodiments, the plurality of nanocrystalline particles can be disposed on a substrate and sintered to form the article. The substrate can be a base or a prior layer of bound particles. In some embodiments, the nanocrystalline particles can be selectively bound together (e.g., sintered) at substantially the same time as they are disposed on the substrate.

A method of additively manufacturing is provided. The method may include successively depositing and fusing together layers of a superalloy powder mixture comprised of a base material powder and a eutectic powder, to build up an additive portion, which eutectic powder has a solidus temperature lower than the solidus temperature of the base material powder. The method may also include heat treating the additive portion at a temperature greater than 1200° C. to heal cracks and/or fill pores and to homogenize the alloy of which the additive portion is comprised. The additive portion alloy has a chemistry defined by the superalloy powder mixture. The base material powder may be formed of a nickel-base superalloy with an aluminum content by weight of at least 1.5%. The eutectic powder may be a nickel-base alloy including by weight about 6% to about 11% chromium, about 5% to about 9% titanium, and about 9% to about 13% zirconium, with balance nickel as its primary components.

A method of additively manufacturing is provided. The method may include successively depositing and fusing together layers of a superalloy powder mixture comprised of a base material powder and a eutectic powder, to build up an additive portion, which eutectic powder has a solidus temperature lower than the solidus temperature of the base material powder. The method may also include heat treating the additive portion at a temperature greater than 1200° C. to heal cracks and/or fill pores and to homogenize the alloy of which the additive portion is comprised. The additive portion alloy has a chemistry defined by the superalloy powder mixture. The base material powder may be formed of a nickel-base superalloy with an aluminum content by weight of at least 1.5%. The eutectic powder may be a nickel-base alloy including by weight about 6% to about 11% chromium, about 5% to about 9% titanium, and about 9% to about 13% zirconium, with balance nickel as its primary components.

Embodiments can relate to an improved hydroflux, additive or electroless plating assisted densification cold sintering process to densify powdered metals at lower compaction pressures and lower temperatures (e.g., 520 MPa and 140° C.). The process can involve inducing dissolution precipitation mechanisms at powder interfaces by introducing a transport phase (formed by the introduction of water during the process to suppress melting temperatures) that is not an aqueous solution. Particle interfaces in the cold sinter fuse together by the presence of the additional transport phase, thereby reducing the temperatures and pressures needed for compaction. Some embodiments involve the use of elements to form a eutectic at the desired low temperature, thereby stabilizing certain crystal structure shapes of isometric crystal systems, inducing rapid densification, and facilitating pore smoothing. Embodiments of the process can be used to generate a green compact via sintering that exhibits improved green strength.

Described herein are kits, methods, and systems for printing metal three-dimensional objects. In an example, described is a kit for three-dimensional printing comprising: powdered metal build material; and a binding fluid comprising a liquid vehicle, metal or metal precursor particles, and latex polymer particles dispersed in the liquid vehicle, wherein the latex polymer particles have an average particle size of from about 10 nm to about 300 nm, and wherein the metal or metal precursor particles comprise metal nanoparticles, metal oxide nanoparticles, metal oxide nanoparticles and a reducing agent, or combinations thereof.

Described herein are kits, methods, and systems for printing metal three-dimensional objects. In an example, described is a kit for three-dimensional printing comprising: powdered metal build material; and a binding fluid comprising a liquid vehicle, metal or metal precursor particles, and latex polymer particles dispersed in the liquid vehicle, wherein the latex polymer particles have an average particle size of from about 10 nm to about 300 nm, and wherein the metal or metal precursor particles comprise metal nanoparticles, metal oxide nanoparticles, metal oxide nanoparticles and a reducing agent, or combinations thereof.

A joining material for bonding overlapping components of a power electronic device together via a liquid phase sintering process. The joining material includes a mixture of composite particles. Each of the composite particles exhibits a core-shell structure having a core made of a copper-based material and a shell surrounding the core that is made of a low melting point material having a melting temperature or a solidus temperature less than that of the copper-based material of the core. The mixture of composite particles includes a first particulate fraction having a first median particle size and a second particulate fraction having a second median particle size. The first median particle size is at least one order of magnitude larger than the second median particle size.

A joining material for bonding overlapping components of a power electronic device together via a liquid phase sintering process. The joining material includes a mixture of composite particles. Each of the composite particles exhibits a core-shell structure having a core made of a copper-based material and a shell surrounding the core that is made of a low melting point material having a melting temperature or a solidus temperature less than that of the copper-based material of the core. The mixture of composite particles includes a first particulate fraction having a first median particle size and a second particulate fraction having a second median particle size. The first median particle size is at least one order of magnitude larger than the second median particle size.

The present invention is directed toward an additive manufacturing method for manufacturing silica-based structures that have a low linear cure shrinkage percentage and an ultra-low coefficient of thermal expansion. The structure may be constructed with a powder mixture that contains at least a first set of silica-based particles that are spherical and that have a first size, and a second set of submicron silica-based particles that are jagged, spherical, or both jagged and spherical. The silica-based powder mixture may be combined with a surfactant in order to create a slurry that can be used to create a 3D printed structure that has a low linear cure shrinkage percentage and an ultra-low coefficient of thermal expansion.