Composite material turbine engine vane, and method for manufacturing same

1. A method of fabricating a turbomachine blade out of a composite material comprising fiber reinforcement densified by a matrix, the method comprising:

making a one-piece fiber blank by three-dimensional weaving;

shaping the fiber blank to obtain a one-piece fiber preform having a first portion forming a blade airfoil and root preform and at least one second portion forming a preform for an inner or outer blade platform; and

densifying the preform with a matrix to obtain a composite material blade having fiber reinforcement constituted by the preform and densified by the matrix, forming a single part with incorporated inner and/or outer platform,

wherein the one-piece fiber blank is woven to comprise a first part which is to constitute, after shaping, the first portion of the fiber preform and a second part which is to constitute, after shaping, the second portion of the fiber preform, and

wherein, in the longitudinal direction of the fiber blank that corresponds to the longitudinal direction of the blade that is to be made, the fiber blank comprises a first set of a plurality of layers of yarns that are linked together to form a first portion of the blank that corresponds to the preform for the blade airfoil and root, and a second set of a plurality of layers of yarns that are linked together at least locally to form at least one second portion of the blank that corresponds to a preform for an inner or outer blade platform, wherein the yarns of the first set of layers of yarns are not linked to the yarns of the second set of layers of yarns and wherein yarns of the second set of layers of yarns cross through the first set of layers of yarns at the level of the or each second portion of the blank.

2. A method according to claim 1 , wherein the fiber blank is woven with a second continuous set of layers of yarns and the shaping of the fiber blank comprises eliminating portions of the second set of layers of yarns external to the or each second portion of the fiber blank by cutting them away.

3. A method according to claim 1 , wherein, at the location or at least at one of the locations where yarns of the second set of layers of yarns cross through the first set of layers of yarns, the intersection between a layer of yarns of the first set and a layer of yarns of the second set follows a line that is not orthogonal to the longitudinal direction of the fiber blank.

4. A method according to claim 1 , wherein, in the first portion of the fiber blank and in a direction that corresponds to the direction extending along the profile of an airfoil of varying thickness in the blade that is to be made, the number of layers of yarns in the first set of layers of yarns is constant.

5. A method according to claim 4 , wherein the yarns of the first set of layers of yarns are of varying weights.

6. A method according to claim 4 , wherein the yarns of the first set of layers of yarns are of varying counts.

7. A method according to claim 1 , wherein a strip comprising a succession of fiber blanks is made by three-dimensional weaving.

8. A method according to claim 1 , wherein the blanks are woven with their longitudinal direction that corresponds to the direction of the blades that are to be made extending in the weft direction.

9. A method according to claim 1 , wherein the blanks are woven with their longitudinal direction that corresponds to the direction of the blades that are to be made extending in the warp direction.

10. A turbomachine fitted with a blade fabricated by implementing the method of claim 1 .

11. A turbomachine blade made of composite material comprising fiber reinforcement obtained by three-dimensional weaving of yarns and densified by a matrix, wherein the blade comprises a first portion constituting the blade airfoil and root formed as a single part together with at least one second portion constituting an inner or outer blade platform, and the two portions of the fiber reinforcement that corresponds to the first and second portions of the blade are mutually interlaced at least in part, with yarns of the first portion of the fiber reinforcement penetrating into the second portion of the fiber reinforcement.

12. A blade according to claim 11 , made of ceramic matrix composite material.

13. A blade according to claim 11 , wherein the yarns constitutive of the portion of the fiber reinforcement that corresponds to the second portion of the blade cross through the portion of the fiber reinforcement that corresponds to the first portion of the blade.

14. A blade according to claim 11 , wherein the airfoil of the blade has a profile of varying thickness, along which the portion of the fiber reinforcement that corresponds to the first portion of the blade has a constant number of layers of yarns extending in the longitudinal direction of the blade and having varying weights and/or counts.

15. A blade according to claim 11 , wherein the airfoil of the blade has a profile of varying thickness, along which the portion of the fiber reinforcement that corresponds to the first portion of the blade has a varying number of layers of yarns extending in the longitudinal direction of the blade.

16. A turbomachine fitted with a blade according to claim 11 .