Process for manufacturing a thermostructural composite part

A method of fabricating a composite material part comprising fiber reinforcement densified by a matrix, said method comprising the steps of:

• making a fiber preform consolidated by impregnating a fiber texture made up of yarns with a liquid consolidation composition containing a precursor for a consolidating material, and by transforming the precursor into consolidating material by pyrolysis so as to obtain a consolidated preform that is held in shape;
• and
• densifying the consolidated fiber preform by chemical vapor infiltration;
• the method being characterized in that it includes, prior to impregnation of the fiber texture with the consolidation liquid composition and prior to chemical vapor infiltration of the fiber preform, a step of filling the pores of the yarns of said fiber texture by means of a filler composition;
• the method being further characterized in that in the filling step, the quantity of filler liquid composition is selected in such a manner as to fill the internal spaces within the yarns without any overflowing so as to prevent the filler liquid from occupying any of the spaces between the yarns of the fiber texture.