Method for manufacturing a part of complex shape by pressure sintering starting from a preform

A method for manufacturing a part of complex shape by successive deposition of layers according to a technique of 3D additive printing and a pressure sintering, the method comprising the steps of:

• producing a model from a material chosen from porous or pulverulent materials based on a metal alloy, a ceramic, a composite material, or a lost material by formation of successive layers deposited according to a 3D additive printing technique which is digitally controlled;
• producing a preform from the model, the preform is made of porous or pulverulent material derived from the model,
• covering at least one face of the preform with a graphite layer to form an interface layer;
• introducing the preform covered with the graphite layer into a mold filled with sacrificial porous or pulverulent material;
• applying a pressure sintering under a uniaxial densifying pressure to the mold to form the part which is finally extracted from the mold;
• wherein pressure sintering is performed to a load between 50 MPa and 100 Pa and a direct current between 3000 A and 10000 A;
• wherein the 3D additive printing technique is chosen from stereolithography, binder jetting, controlled extrusion, fused filament fabrication, inkjet printing, or aerosol jet printing;
• and wherein the mold is filled with a pulverulent or porous sacrificial material before and after introduction of the preform, the sacrificial material being chosen from a ceramic, a silica, a metal silicate, or a composite material.