The permanent magnet comprises a main phase structure of R.sub.2T.sub.14B crystal grains, and R is a rare earth element; T comprises at least Mn, Fe, and optionally a transition metal comprising Co; B is boron; the permanent magnet further comprises Mn and heavy rare earth elements which are distributed in a grain boundary in a diffusion mode. The heavy rare earth element is selected from at least one selected from Dy, Ho and Tb. According to the rare earth permanent magnet prepared through the preparation method, more heavy rare earth elements can be diffused into the magnet core along the grain boundary, Hcj distribution of the permanent magnet is improved, and meanwhile the corrosion resistance and the mechanical property of the permanent magnet are improved.

A shrouded rotor constructed through a hybrid additive manufacturing process. The shrouded rotor including a hub at a radial center having an outer surface forming an inner wall of a flow path, a shroud at a radial outer side having an inner surface forming an outer wall of the flow path, and vanes extending within the flow path between the hub and the shroud. The outer surface of the hub, the inner surface of the shroud, and all surfaces of the vanes have a surface roughness average of less than 32R.sub.a.

A shrouded rotor constructed through a hybrid additive manufacturing process. The shrouded rotor including a hub at a radial center having an outer surface forming an inner wall of a flow path, a shroud at a radial outer side having an inner surface forming an outer wall of the flow path, and vanes extending within the flow path between the hub and the shroud. The outer surface of the hub, the inner surface of the shroud, and all surfaces of the vanes have a surface roughness average of less than 32R.sub.a.

A lamination molding apparatus includes a chamber, covering at least a molding area which is the maximum range in which a three-dimensional object can be produced; a molding table, disposed in the molding area in the chamber, on which material powder layers are formed by uniformly spread material powder for each of divided layers, wherein the divided layers are obtained by dividing a desired three-dimensional object for each of a specific thickness; a powder holding wall, surrounding the molding table and holding the material powder supplied onto the molding table; a laser irradiation device, forming sintered layers by irradiating laser beam on specific irradiation areas defined by the contour shape of the desired three-dimensional object of the divided layers on the material powder layers; and a numerical control device, determining, at least before sintering, whether the irradiation areas of all the divided layers are included in the molding area.

A lamination molding apparatus includes a chamber, covering at least a molding area which is the maximum range in which a three-dimensional object can be produced; a molding table, disposed in the molding area in the chamber, on which material powder layers are formed by uniformly spread material powder for each of divided layers, wherein the divided layers are obtained by dividing a desired three-dimensional object for each of a specific thickness; a powder holding wall, surrounding the molding table and holding the material powder supplied onto the molding table; a laser irradiation device, forming sintered layers by irradiating laser beam on specific irradiation areas defined by the contour shape of the desired three-dimensional object of the divided layers on the material powder layers; and a numerical control device, determining, at least before sintering, whether the irradiation areas of all the divided layers are included in the molding area.

A method produces a connecting rod from a sintered material, which rod has at least one bore having a center axis, and has a first connecting rod eye in a connecting rod head, and a second connecting rod eye in a connecting rod foot, wherein the connecting rod head is connected with the connecting rod foot with a connecting rod shaft, wherein the bore is configured in the connecting rod shaft, wherein furthermore, the connecting rod is produced from a metallic powder, in accordance with a sintering process, for which purpose the powder is pressed into the corresponding mold to form a green compact, the bore is introduced into the green compact, and the green compact is afterward sintered. The bore is introduced into the green compact as a first and second partial bore, proceeding from the connecting rod foot and from the connecting rod head.

A method produces a connecting rod from a sintered material, which rod has at least one bore having a center axis, and has a first connecting rod eye in a connecting rod head, and a second connecting rod eye in a connecting rod foot, wherein the connecting rod head is connected with the connecting rod foot with a connecting rod shaft, wherein the bore is configured in the connecting rod shaft, wherein furthermore, the connecting rod is produced from a metallic powder, in accordance with a sintering process, for which purpose the powder is pressed into the corresponding mold to form a green compact, the bore is introduced into the green compact, and the green compact is afterward sintered. The bore is introduced into the green compact as a first and second partial bore, proceeding from the connecting rod foot and from the connecting rod head.

A hybrid additive manufacturing process is utilized for creating a shrouded rotor with the shrouded rotor having a hub at a radial center, a shroud at a radial outer side, and vanes extending therebetween. The hybrid additive manufacturing process includes forming the shrouded rotor in stages, with a first stage being formed by depositing material in an axial direction through a first stage of the hub, machining an outer surface of the first stage of the hub to smooth the outer surface, depositing material on the first stage of the hub in a radial direction through a first stage of the vanes and the shroud, and machining all surfaces of the first stage of the vanes and an inner surface of the first stage of the shroud to smooth the surfaces. Subsequent stages of the shrouded rotor are formed similarly to the first stage.

A hybrid additive manufacturing process is utilized for creating a shrouded rotor with the shrouded rotor having a hub at a radial center, a shroud at a radial outer side, and vanes extending therebetween. The hybrid additive manufacturing process includes forming the shrouded rotor in stages, with a first stage being formed by depositing material in an axial direction through a first stage of the hub, machining an outer surface of the first stage of the hub to smooth the outer surface, depositing material on the first stage of the hub in a radial direction through a first stage of the vanes and the shroud, and machining all surfaces of the first stage of the vanes and an inner surface of the first stage of the shroud to smooth the surfaces. Subsequent stages of the shrouded rotor are formed similarly to the first stage.

A method comprising sintering a Mn and Bi powder compact at a first temperature for a first predetermined duration, based on the first temperature, and sintering the compact at a second temperature, less than the first temperature, for a second predetermined duration, greater than the first duration, is disclosed. The sintering at a first temperature for a first predetermined duration generates a predetermined MnBi LTP transition driving force to decrease a formation energy barrier for transition to MnBi LTP. Sintering the compact at the second temperature for the second predetermined duration forms a magnet containing the MnBi LTP.