Method for manufacturing a hollow part made of metal matrix or ceramic matrix composite reinforced with short fibers

A method for manufacturing a hollow part made of ceramic matrix composite, comprising:

• preparing a raw material comprising at least short fibers and a ceramic matrix precursor charge, the short fibers having a length comprised between 50 mm and 100 mm,
• positioning a sacrificial core in a molding cavity of injection-molding equipment, the molding cavity having dimensions larger than dimensions of the sacrificial core,
• shaping the raw material by injection molding said raw material into a free space between the sacrificial core and an internal wall of the molding cavity so as to obtain a green part comprising the sacrificial core and a shaped raw material,
• extracting the green part from the injection-molding equipment,
• densifying the raw material by flash sintering of the green part so as to transform the charge into a ceramic matrix,
• removing the sacrificial core so as to obtain a hollow part made of ceramic matrix composite;
• wherein the sacrificial core is coated with a flexible graphite sheet, with a graphite layer deposited by spraying or with a boron nitride paint layer before the step of injecting the raw material, and
• wherein the sacrificial core has a geometry capable of being unmolded from the densified raw material after said densifying.