Described herein are compositions, methods, and systems for printing metal three-dimensional objects. In an example, described is a method of printing a three-dimensional object comprising: (i) depositing a metal powder build material, wherein the metal powder build material has an average particle size of from about 10 μm to about 250 μm; (ii) selectively applying a binder fluid on at least a portion of the metal powder build material, wherein the binder fluid comprises an aqueous liquid vehicle and latex polymer particles dispersed in the aqueous liquid vehicle; (iii) heating the selectively applied binder fluid on the metal powder build material to a temperature of from about 40° C. to about 180° C.; and (iv) repeating (i), (ii), and (iii) at least one time to form the three-dimensional object.

A gear includes a sintered body, in which Fe is contained as a principal component, Ni is contained in a proportion of 2 mass % or more and 20 mass % or less, Si is contained in a proportion of 0.3 mass % or more and 5.0 mass % or less, C is contained in a proportion of 0.005 mass % or more and 0.3 mass % or less, and one element selected from the group consisting of Ti, V, Y, Zr, Nb, Hf, and Ta is defined as a first element, that is contained in a proportion of 0.01 mass % or more and 0.7 mass % or less.

A gear includes a sintered body, in which Fe is contained as a principal component, Ni is contained in a proportion of 2 mass % or more and 20 mass % or less, Si is contained in a proportion of 0.3 mass % or more and 5.0 mass % or less, C is contained in a proportion of 0.005 mass % or more and 0.3 mass % or less, and one element selected from the group consisting of Ti, V, Y, Zr, Nb, Hf, and Ta is defined as a first element, that is contained in a proportion of 0.01 mass % or more and 0.7 mass % or less.

A material for producing a three-dimensionally printed part including a metal material and at least one sintering aid in an amount effective to give the three-dimensionally printed part a density of between about 90% and about 100% after sintering is disclosed. A method of printing a three-dimensional part including selecting a metal material, incorporating at least one sintering aid into the metal material to form a print material, and printing the three-dimensional part is also disclosed. A method of producing a sintered metal part including providing a metal material for the sintered metal part incorporating boron as a first sintering aid, incorporating phosphorus as a second sintering aid, forming the metal part in a predetermined form the metal material, and heating the formed metal part to a sintering temperature is also disclosed. Three-dimensionally printed parts are also disclosed.

A material for producing a three-dimensionally printed part including a metal material and at least one sintering aid in an amount effective to give the three-dimensionally printed part a density of between about 90% and about 100% after sintering is disclosed. A method of printing a three-dimensional part including selecting a metal material, incorporating at least one sintering aid into the metal material to form a print material, and printing the three-dimensional part is also disclosed. A method of producing a sintered metal part including providing a metal material for the sintered metal part incorporating boron as a first sintering aid, incorporating phosphorus as a second sintering aid, forming the metal part in a predetermined form the metal material, and heating the formed metal part to a sintering temperature is also disclosed. Three-dimensionally printed parts are also disclosed.

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 of manufacturing a component includes making a preform from a powdered material, the preform having a density in a range from 70 to 95% of theoretical density of the material, The method also includes sintering the preform using a Field Assisted Sintering Technique (FAST) process to produce a component having a density of greater than 97% of the theoretical density of the material. Components, in particular low aspect components, formed by said method are also described.

A method of manufacturing a component includes making a preform from a powdered material, the preform having a density in a range from 70 to 95% of theoretical density of the material, The method also includes sintering the preform using a Field Assisted Sintering Technique (FAST) process to produce a component having a density of greater than 97% of the theoretical density of the material. Components, in particular low aspect components, formed by said method are also described.

A method for connecting a first component to a second component to form an assembly forms a press fit connection between the first component and the second component, for which purpose the second component is produced having an annular component section. A recess is formed, in which the first component is at least partially arranged. At least the annular component section of the second component is produced as a sintered component and has net shape or near net shape quality at least in the region of the recess.

A method for connecting a first component to a second component to form an assembly forms a press fit connection between the first component and the second component, for which purpose the second component is produced having an annular component section. A recess is formed, in which the first component is at least partially arranged. At least the annular component section of the second component is produced as a sintered component and has net shape or near net shape quality at least in the region of the recess.