A method of additively manufacturing a monolithic metal article having a three-dimensional shape is disclosed. The method involves forming a preform of the article that includes atomized metal particles bound together by a binder material. The atomized metal particles, more specifically, comprises (1) water atomized metal particles and (2) gas atomized metal particles, plasma atomized metal particles, or a mixture of gas atomized metal particles and plasma atomized metal particles. The water atomized metal particles may be contained in one portion of the preform and the gas and/or plasma atomized metal particles may be contained in another portion of the preform. The method also includes removing at least a portion of the binder material from the preform and sintering the preform to transform the preform into the monolithic metal article.

A cylinder head assembly for an internal combustion engine includes a main body, a valve seat insert, and at least one flow passage extending through the main body. The main body may be formed from a first material and defines a recess configured to cooperate with an associated cylinder bore and piston to form a combustion chamber. The flow passage may extend through the main body from the recess. The valve seat insert may be disposed within the recess proximate to an end of the flow passage. The valve seat insert includes a thermally conductive layer of powdered metal having an upper side disposed adjacent to the main body, a hardness layer of powdered metal, and a machining layer of powdered metal.

A cylinder head assembly for an internal combustion engine includes a main body, a valve seat insert, and at least one flow passage extending through the main body. The main body may be formed from a first material and defines a recess configured to cooperate with an associated cylinder bore and piston to form a combustion chamber. The flow passage may extend through the main body from the recess. The valve seat insert may be disposed within the recess proximate to an end of the flow passage. The valve seat insert includes a thermally conductive layer of powdered metal having an upper side disposed adjacent to the main body, a hardness layer of powdered metal, and a machining layer of powdered metal.

An additive manufacturing apparatus includes: a build drum, the build drum having a peripheral wall defining a worksurface, the build drum being mounted for rotation about a central axis; a drive mechanism operable to rotate the build drum about the central axis, to hold a solidifiable material on the worksurface by centrifugal force; and a material deposition and solidification apparatus, including: a material depositor operable to deposit the solidifiable material on the worksurface; and an apparatus operable to selectively solidify the solidifiable material.

An iron alloy powder consists of, when the entirety thereof is assumed to be 100 mass %, Cr: 2.5 mass % to 3.5 mass %, Mo: 0.4 mass % to 0.6 mass %, and Fe and inevitable impurities as the balance, a mixed powder consisting of 15 mass % to 40 mass % of the iron alloy powder, 1.2 mass % to 1.8 mass % of a copper powder, 0.5 mass % to 1.0 mass % of a graphite powder, and a pure iron powder as the balance when the entire mixed powder is assumed to be 100 mass % is compacted into a compact, and the compact is sintered while transforming a structure derived from the pure iron powder into a structure in which a ferritic structure and a pearlitic structure are mixed and transforming a structure derived from the iron alloy powder into a martensitic structure.

An iron alloy powder consists of, when the entirety thereof is assumed to be 100 mass %, Cr: 2.5 mass % to 3.5 mass %, Mo: 0.4 mass % to 0.6 mass %, and Fe and inevitable impurities as the balance, a mixed powder consisting of 15 mass % to 40 mass % of the iron alloy powder, 1.2 mass % to 1.8 mass % of a copper powder, 0.5 mass % to 1.0 mass % of a graphite powder, and a pure iron powder as the balance when the entire mixed powder is assumed to be 100 mass % is compacted into a compact, and the compact is sintered while transforming a structure derived from the pure iron powder into a structure in which a ferritic structure and a pearlitic structure are mixed and transforming a structure derived from the iron alloy powder into a martensitic structure.

A method for manufacturing an insert for an aluminum piston comprises applying pressure to a composition that comprises aluminum. The composition is deformed to form the insert for aluminum piston. The insert comprises an aluminum alloy and the insert functions as a ring carrier. Disclosed herein too is an article that comprises an insert for a piston. The article is manufactured from a composition that comprises aluminum. The insert is manufactured by a process that comprises applying pressure to the composition to form the insert.

A method for manufacturing an insert for an aluminum piston comprises applying pressure to a composition that comprises aluminum. The composition is deformed to form the insert for aluminum piston. The insert comprises an aluminum alloy and the insert functions as a ring carrier. Disclosed herein too is an article that comprises an insert for a piston. The article is manufactured from a composition that comprises aluminum. The insert is manufactured by a process that comprises applying pressure to the composition to form the insert.

A method for manufacturing an insert for an aluminum piston comprises applying pressure to a composition that comprises aluminum. The composition is deformed to form the insert for aluminum piston. The insert comprises an aluminum alloy and the insert functions as a ring carrier. Disclosed herein too is an article that comprises an insert for a piston. The article is manufactured from a composition that comprises aluminum. The insert is manufactured by a process that comprises applying pressure to the composition to form the insert.

Some variations provide a process for additive manufacturing of a nanofunctionalized metal alloy, comprising: providing a nanofunctionalized metal precursor containing metals and grain-refining nanoparticles; exposing a first amount of the nanofunctionalized metal precursor to an energy source for melting the precursor, thereby generating a first melt layer; solidifying the first melt layer, thereby generating a first solid layer; and repeating many times to generate a plurality of solid layers in an additive-manufacturing build direction. The additively manufactured, nanofunctionalized metal alloy has a microstructure with equiaxed grains. Other variations provide an additively manufactured, nanofunctionalized metal alloy comprising metals selected from aluminum, iron, nickel, copper, titanium, magnesium, zinc, silicon, lithium, silver, chromium, manganese, vanadium, bismuth, gallium, or lead; and grain-refining nanoparticles selected from zirconium, tantalum, niobium, titanium, or oxides, nitrides, hydrides, carbides, or borides thereof, wherein the additively manufactured, nanofunctionalized metal alloy has a microstructure with equiaxed grains.