A graphene-reinforced alloy composite material and a preparation method thereof are disclosed. The method includes preparing a porous graphene colloid, smelting a first-part alloy, pouring it into the porous graphene colloid to be formed, subjecting the formed product to a hot extrusion, and pulverizing into a powder I; smelting a second-part alloy into an alloy melt II, adding a high-purity silicon powder therein, mixing by stirring, and atomizing to obtain a powder II; mixing the powder I and the powder II, to obtain a pretreated alloy powder; placing the pretreated alloy powder in a high-purity ark, transferring the high-purity ark to a high-temperature tubular furnace, subjecting the pretreated alloy powder to a redox treatment, and introducing methane and hydrogen to grow graphene, to obtain a coated alloy powder; subjecting the coated alloy powder to a pre-compressing molding and sintering, to obtain the graphene-reinforced alloy composite material.

A method for producing material powder, comprising providing material and an atomization gas charged with an atomization gas pressure by means of an atomization gas compressor to an atomization device, melting the material and pulverizing the molten material into material powder by means of charging the molten material with the atomization gas using the atomization introducing the material powder from the atomization device into a pressurized container and providing a conveyor gas charged with a conveyer gas pressure by means of a conveyer gas compressor to the pressurized container, wherein the conveyor gas pressure is higher than the atmospheric pressure and lower than the atomization gas pressure, as well as a device for carrying out the method.

A method of carburizing a powder metal part involving more than one carburizing step. In a pre-forging carburizing step, a powder metal part that is less than fully dense is carburized to establish a pre-forging carburization profile. After the pre-forging carburizing step, the powder metal part is forged so that the powder metal part is increased in density and the pre-forging carburization profile is transformed into an as-forged carburization profile. In a post-forging carburizing step following the forging step, the powder metal part is again carburized, thereby resulting in both further diffusion of carbon from the as-forged carburization profile into the powder metal part and further introduction of carbon into the powder metal part at a surface of the powder metal part.

A method of carburizing a powder metal part involving more than one carburizing step. In a pre-forging carburizing step, a powder metal part that is less than fully dense is carburized to establish a pre-forging carburization profile. After the pre-forging carburizing step, the powder metal part is forged so that the powder metal part is increased in density and the pre-forging carburization profile is transformed into an as-forged carburization profile. In a post-forging carburizing step following the forging step, the powder metal part is again carburized, thereby resulting in both further diffusion of carbon from the as-forged carburization profile into the powder metal part and further introduction of carbon into the powder metal part at a surface of the powder metal part.

A treated additive manufactured article is disclosed. The article comprises a shaped metal alloy having a treated surface layer and a core. At least one of the average hardness of the treated surface layer is greater than the average hardness of the core, and the average corrosion resistance of the treated surface layer is greater than the average corrosion resistance of the core.

A treated additive manufactured article is disclosed. The article comprises a shaped metal alloy having a treated surface layer and a core. At least one of the average hardness of the treated surface layer is greater than the average hardness of the core, and the average corrosion resistance of the treated surface layer is greater than the average corrosion resistance of the core.

A method and apparatus for surface densification of powder metal annular preforms is described. A forming tool has external helical teeth corresponding to internal helical teeth of the preform. A die correspondingly configured to the external splines of the preform circumferentially surrounds the forming tool. The forming tool, die and lower punch(es) collectively define an aperture dimensioned to receive the preform. Upper punch(es) encase the preform in the aperture. Surface densification of the internal surface of the preform is achieved by movement of the preform axially over the forming tool. External splines of the preform and corresponding die splines direct the preform axially while internal helical teeth and corresponding forming teeth direct the forming tool to rotate as the preform moves. The forming teeth have varying dimensions in the circumferential and radial directions to apply compression and relaxation to densify the surface of the preform helical teeth.

A method and apparatus for surface densification of powder metal annular preforms is described. A forming tool has external helical teeth corresponding to internal helical teeth of the preform. A die correspondingly configured to the external splines of the preform circumferentially surrounds the forming tool. The forming tool, die and lower punch(es) collectively define an aperture dimensioned to receive the preform. Upper punch(es) encase the preform in the aperture. Surface densification of the internal surface of the preform is achieved by movement of the preform axially over the forming tool. External splines of the preform and corresponding die splines direct the preform axially while internal helical teeth and corresponding forming teeth direct the forming tool to rotate as the preform moves. The forming teeth have varying dimensions in the circumferential and radial directions to apply compression and relaxation to densify the surface of the preform helical teeth.

Alloy compositions for 3D metal printing procedures which provide metallic parts with high hardness, tensile strengths, yield strengths, and elongation. The alloys include Fe, Cr and Mo and at least three or more elements selected from C, Ni, Cu, Nb, Si and N. As built parts indicate a tensile strength of at least 1000 MPa, yield strength of at least 640 MPa, elongation of at least 3.0% and hardness (HV) of at least 375.

According to a several embodiment, provided is a method for manufacturing a molded object, including a material preparing step to prepare a material powder obtained by removing carbon from medium carbon steel or high carbon steel until a carbon content is 0.1 mass % or less, a molding step to form a desired molded object by a lamination molding method repeating the steps of: a recoating step to uniformly spread the material powder on a molding table to form a material powder layer; and a sintering step to irradiate a predetermined portion of the material powder layer with a laser beam to form a sintered layer; and a carburization step to subject the molded object to carburization after the molding step is performed.