Method of fabricating a composite material turbine engine vane with incorporated platforms

1. A method of fabricating a turbine engine vane out of composite material, the vane comprising an airfoil secured to inner and outer platforms which extend in a lateral direction around a circumference of the airfoil, the method comprising the following steps:

using multilayer weaving to form a fiber blank having a longitudinal direction corresponding to the direction of the vane to be made and including in its thickness a first woven portion with a plurality of yarn layers that are interlinked by weaving, a second woven portion, and a third woven portion, the first portion being situated between the third portion and the second portion and being interlinked therewith by weaving over only a fraction of its longitudinal dimension;

using the fiber blank to form a preform for the vane to be made, by folding out, on either side of the first portion, segments of the second and third portions that are not interlinked with the first portion, by shaping the first portion to form a preform portion for the airfoil of the vane to be made, and by shaping the folded-out segments of the second and third portions to form preform portions for the inner and outer platforms of the vane to be fabricated, said folded-out segments of the second and third portions extend in a lateral direction around a circumference of the first portion; and

densifying the vane preform with a matrix to obtain a composite material vane having incorporated inner and outer platforms.

2. A method according to claim 1 , wherein the first portion of the blank presents an internal non-interlinked zone between two layers of adjacent yarns that extends over the entire longitudinal dimension of the first portion of the blank and that is open solely at the longitudinal ends of the first portion of the blank in such a manner as to form, once shaped, a preform portion for a hollow airfoil.

3. A method according to claim 1 , wherein the segments of the second and third portions of the blank that are not interlinked with the first portion are situated in longitudinal end portions of the second and third portions of the blank.

4. A method according to claim 1 , wherein the second and third portions of the blank are interlinked by weaving with the first portion of the blank in longitudinal end portions, and the segments of the second and third portions of the blank that are not interlinked with the first portion of the blank extend between said longitudinal end portions.

5. A method according to claim 1 , wherein the preform portion for the airfoil has a width that is less than the widths of the preform portions for the inner and outer platforms, and the excess width of the first portion of the blank is eliminated by being cut off in order to shape the preform portion for the airfoil while allowing interlinking to remain between the second and third portions of the blank, via a region of the first portion of the blank, across the entire width of the blank along the connections of said segments with the remainder of the blank.

6. A method according to claim 1 , wherein, in order to make a vane for a turbine nozzle or a compressor diffuser, the vane preform is formed with an outer extension extending beyond the preform portion for the outer platform, on its outside, and, while making the vane preform, the outer extension is shaped to form a preform portion for a mounting portion for mounting in a turbine or compressor casing.

7. A method according to claim 1 , wherein, in order to make a vane for a turbine nozzle or a compressor diffuser, the vane preform is formed with an inner extension extending beyond the preform portion for the inner platform, on its inside, and, while making the vane preform, the inner extension is shaped to form a preform portion for an attachment portion.

8. A method of fabricating a turbine engine vane out of composite material, the vane comprising an airfoil secured to inner and outer platforms, the method comprising the following steps:

using multilayer weaving to form a fiber blank having a longitudinal direction corresponding to the direction of the vane to be made and including in its thickness a first woven portion with a plurality of yarn layers that are interlinked by weaving, a second woven portion, and a third woven portion, the first portion being situated between the third portion and the second portion and being interlinked therewith by weaving over only a fraction of its longitudinal dimension;

using the fiber blank to form a preform for the vane to be made, by folding out, on either side of the first portion, segments of the second and third portions that are not interlinked with the first portion, by shaping the first portion to form a preform portion for the airfoil of the vane to be made, and by shaping the folded-out segments of the second and third portions to form preform portions for the inner and outer platforms of the vane to be fabricated; and

densifying the vane preform with a matrix to obtain a composite material vane having incorporated inner and outer platforms; and

wherein the preform portion for the airfoil has a width that is less than the widths of the preform portions for the inner and outer platforms, and the excess width of the first portion of the blank is eliminated by being cut off in order to shape the preform portion for the airfoil while allowing interlinking to remain between the second and third portions of the blank, via a region of the first portion of the blank, across the entire width of the blank along the connections of said segments with the remainder of the blank.