Methods of increasing density of 3D-printed and sintered parts

A method of printing a three-dimensional part, comprising:

• selecting a metal material for the three-dimensional part, wherein the metal material is in the form of a powderized metal material in a powder bed or comprises a filament;
• incorporating a sintering aid combination comprising boron as a first sintering aid and phosphorus as a second sintering aid into the metal material in an amount effective to give the three-dimensional part a density of between about 90% and about 100% after sintering to form a print material;
• and
• printing the three-dimensional part by forming sequential layers of the print material in a predetermined form.

A three-dimensionally printed part comprising:

• a top portion;
• a bottom portion;
• and
• a plurality of sequential layers arranged in a predetermined form between the top portion and the bottom portion, the plurality of sequential layers formed of a print material comprising a metal material, wherein the metal material is in the form of a powderized metal material in a powder bed or comprises a filament, and a sintering aid combination comprising boron as a first sintering aid and phosphorus as a second sintering aid in an amount effective to give the three-dimensionally printed part a density of between about 90% and about 100% after sintering.