Turbine engine hybrid rotor

Abstract

A turbine engine rotor component has a Ti-based first member (66) circumscribing an axis (500) and has either a circumferential array of integrally formed airfoils (62) or a circumferential array of blade retention features. A TiB particulate reinforced second member (90) also circumscribes the axis.

Claims

1. A turbine engine rotor component comprising: a Ti-based first member (6) circumscribing an axis (500) and having either a circumferential array of integrally-formed airfoils (62) or a circumferential array of blade retention features; and a TiB.sub.w particulate-reinforced second member (90) circumscribing the axis.

2. The component of claim 1 wherein: the second member is diffusion bonded to the first member.

3. The component of claim 1 wherein at 28 C. one to all of: the second member has higher yield tensile strength than the first member; the second member has higher ultimate tensile strength than the first member; the second member has higher modulus than the first member; the first member is more machinable than the second member; and the first member has higher fatigue strength than the second member.

4. The component of claim 3 wherein: the second member is a powder-metallurgical member.

5. The component of claim 4 wherein: the first member is a non-powder-metallurgical member.

6. The component of claim 5 wherein: the first member and the second member each account for at least 20% of weight of the turbine engine rotor component.

7. The component of claim 1 wherein one or both of: the second member has higher boron content than the first member; and the second member has higher TiB than the first member.

8. The component of claim 1 wherein in axial cross-section: the first member has a pocket (120) open either one or more of inboard, outboard, fore, and aft; and the second member is accommodated in the pocket.

9. The component of claim 1 wherein: the component lacks a protuberant bore.

10. A method for manufacturing the component of claim 1, the method comprising: forming the first member; forming the second member; and securing the second member to the first member.

11. The method of claim 10 wherein the securing comprises diffusion bonding.

12. The method of claim 11 wherein: the forming of the first member comprises a non-powder-metallurgical technique; and the forming of the second member comprises a powder-metallurgical technique.

13. A turbine engine rotor component comprising: a Ti-based first member (66) circumscribing an axis (500) and having either a circumferential array of integrally-formed airfoils (62) or a circumferential array of blade retention features; and a TiB particulate-reinforced second member (90) circumscribing the axis, wherein one to all of: the first member has a boron content of less than 0.1% by weight; the first member has a 28 C. ultimate tensile strength of less than 1.25 GPa; the second member has a boron content of at least 0.5% by weight; and the second member has a 28 C. ultimate tensile strength of more than 1.38 GPa.

14. The component of claim 13 wherein one to all of: the first member has a boron content of less than 0.05% by weight; the first member has a 28 C. ultimate tensile strength of less than 1.10 GPa; the second member has a boron content of 0.5-2.0% by weight; and the second member has a 28 C. ultimate tensile strength of more than 1.17 GPa.

15. A turbine engine (20) comprising: an engine case (22); and a compressor component comprising: a Ti-based first member (66) circumscribing an axis (500) and having either a circumferential array of integrally-formed airfoils (62) or a circumferential array of blade retention features; and a TiB particulate-reinforced second member (90) circumscribing the axis.

16. The turbine engine of claim 15 wherein: the compressor component is an integrally-bladed ring.

17. The turbine engine of claim 15 wherein: the second member is accommodated in a pocket (120) of the first member and is partially exposed.

18. The turbine engine of claim 15 wherein: the second member is diffusion bonded to the first member.

19. A turbine engine rotor component comprising: a Ti-based first member (66) circumscribing an axis (500) and having either a circumferential array of integrally-formed airfoils (62) or a circumferential array of blade retention features; and a TiB particulate-reinforced second member (90) circumscribing the axis, wherein in axial cross-section: the first member has a pocket (120) open one of fore and aft and closed inboard and outboard; and the second member is accommodated in the pocket.

20. A turbine engine rotor component comprising: a Ti-based first member (66) circumscribing an axis (500) and having either a circumferential array of integrally-formed airfoils (62) or a circumferential array of blade retention features; and a TiB particulate-reinforced second member (90) circumscribing the axis, wherein: the first member and the second member each account for at least 20% of weight of the turbine engine rotor component; and at 28 C. one to all of: the second member has higher yield tensile strength than the first member; the second member has higher ultimate tensile strength than the first member; the second member has higher modulus than the first member; the first member is more machinable than the second member; and the first member has higher fatigue strength than the second member.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) FIG. 1 is a partially schematic longitudinal sectional view of a gas turbine engine.

(2) FIG. 1A is an enlarged view of a blade ring of the engine of FIG. 1.

(3) FIG. 2 is a table of properties of various materials.

(4) FIG. 3 is an enlarged sectional view of an alternate blade ring.

(5) Like reference numbers and designations in the various drawings indicate like elements.

DETAILED DESCRIPTION

(6) FIG. 1 shows a gas turbine engine. FIG. 1 shows a gas turbine engine 20 having an engine case 22 surrounding a centerline or central longitudinal axis 500. An exemplary gas turbine engine is a turbofan engine having a fan section 24 including a fan 26 within a fan case 28. The exemplary engine includes an inlet 30 at an upstream end of the fan case receiving an inlet flow along an inlet flowpath 520. The fan 26 has one or more stages of fan blades 32. Downstream of the fan blades, the flowpath 520 splits into an inboard portion 522 being a core flowpath and passing through a core of the engine and an outboard portion 524 being a bypass flowpath exiting an outlet 34 of the fan case.

(7) The core flowpath 522 proceeds downstream to an engine outlet 36 through one or more compressor sections, a combustor, and one or more turbine sections. The exemplary engine has two axial compressor sections and two axial turbine sections, although other configurations are equally applicable. From upstream to downstream there is a low pressure compressor section (LPC) 40, a high pressure compressor section (HPC) 42, a combustor section 44, a high pressure turbine section (HPT) 46, and a low pressure turbine section (LPT) 48. Each of the LPC, HPC, HPT, and LPT comprises one or more stages of blades which may be interspersed with one or more stages of stator vanes.

(8) In the exemplary engine, the blade stages of the LPC and LPT are part of a low pressure spool mounted for rotation about the axis 500. The exemplary low pressure spool includes a shaft (low pressure shaft) 50 which couples the blade stages of the LPT to those of the LPC and allows the LPT to drive rotation of the LPC. In the exemplary engine, the shaft 50 also directly drives the fan. In alternative implementations, the fan may be driven via a transmission (e.g., a fan gear drive system such as an epicyclic transmission) to allow the fan to rotate at a lower speed than the low pressure shaft.

(9) The exemplary engine further includes a high pressure shaft 52 mounted for rotation about the axis 500 and coupling the blade stages of the HPT to those of the HPC to allow the HPT to drive rotation of the HPC. In the combustor 44, fuel is introduced to compressed air from the HPC and combusted to produce a high pressure gas which, in turn, is expanded in the turbine sections to extract energy and drive rotation of the respective turbine sections and their associated compressor sections (to provide the compressed air to the combustor) and fan.

(10) FIG. 1A shows a compressor blade stage 60 of a rotor of the engine of FIG. 1. The exemplary blade stage is an integrally bladed stage wherein the blade airfoils 62 are integrally formed as a single piece including a rim, band, or ring portion 64 of a first member 66 circumscribing the engine axis. The first member includes a radially outboard surface 68 (locally forming an inboard boundary of the core gaspath) from which the airfoils protrude. The exemplary first member is formed of a Ti alloy. More particularly, it is formed of a relatively inexpensive conventional wrought Ti-based alloy. The portion of the first member 66 inboard of the airfoil 62 combines with a second member to form a disk 70.

(11) FIG. 1A further shows the second member 90 mounted/joined to the first member. The exemplary second member is a full-annulus ring 90 of a powder metallurgical (PM) Ti-based alloy. Utilizing a very high strength (e.g., >200 ksi) TiB particulate-reinforced ring 90 in place of a Ti MMC ring can save similar weight without the cost and anisotropic properties found with conventional Ti-MMCs. The ring could be diffusion bonded or forge joined to the first ring. The conventional and particulate reinforced materials could also be co-extruded or hot isostatically pressed to join them. Similarly, conventional airfoils could be diffusion bonded or linear friction welded to the second ring without a first ring (FIG. 3). Additive manufacturing techniques can also be used to create conventional airfoils on a particulate-reinforced ring. The first ring 64 may have good HCF or temperature capability. Fabrication methods for the first ring and the mating of the second ring may be similar for those used to join continuous fiber MMC rings. However, due to the isotropic thermal expansion of particulate-reinforced ring, other joining methods are also applicable.

(12) Viewed in axial cross-section, the second ring is formed as an axially-elongate rectangle, having an outboard surface 92, an inboard surface 94, a forward/front/upstream surface 96 and a rear/back/aft surface 98.

(13) FIG. 2 (Table I) shows properties of various candidate materials for the first ring, second ring, and prior art MMC second ring. The exemplary second ring is a TiB particulate-reinforced titanium member.

(14) Thus, for example a conventional Ti-6-4 first member may offer low cost. The addition of a high strength, high modulus PM second member may provide higher performance than in the absence of the second member at less cost than other high performance options such as fiber-reinforcement (continuous fiber MMC). Thus, one group of examples involves using one of the lower yield strength wrought alloys (rather than one of the higher yield strength wrought alloys) for the first member and one of the higher yield strength TiB particulate-reinforced alloys for the second member. These higher strength TiB particulate-reinforced alloys may have room temperature isotropic UTS nearly as high (e.g., within about 20%, more narrowly, within about 15%) of the corresponding longitudinal UTS of the anisotropic long fiber Ti MMC. Thus, exemplary room temperature (20 C. or 28 C.) UTS of the second member may be at least 1.35 GPa (more narrowly, at least 1.45 GPa) while room temperature UTS of the first member may be less than 1.25 GPa (more narrowly, less than 1.15 GPa) for such exemplary combinations of relatively low strength wrought alloys and relatively high strength TiB particulate-reinforced.

(15) The exemplary second member is at least partially accommodated in a compartment 120 of the first member. The exemplary compartment is forwardly open and closed inboard by an inner rim section 140. In the exemplary embodiment, the inner rim section 140 is joined to the outer rim portion 64 by a radial web 142. This illustration is merely illustrative and schematic. Particularly, the first member would be expected to have complex surface geometry including things such as features for engaging seals, features for engaging other rings, features for engaging tie rods, and the like.

(16) An exemplary manufacture sequence includes forming the first member by forging and machining (or other conventional process, more particularly in some embodiments a non-powder metallurgical process).

(17) An exemplary manufacture sequence includes forming the second member by extruding, forging to form a large pancake, and then machining out an annular ring. An alternative involves a hot isostatic pressing (HIP) of a powder compact and machining. Another alternative involves extruding a powder compact (absent forging) and machining. Other alternatives involve HIP followed by forging.

(18) An exemplary manufacture sequence includes joining the second member to the first member by forge joining.

(19) Alternatives involve diffusion bonding, HIP bonding, co-extrusion, or linear friction welding.

(20) FIG. 3 shows an alternate blade stage 60 wherein a series of individual blades 62 are secured to a TiB particulate reinforced member 90. The exemplary member 90 substantially forms the disk alone (e.g., without a continuation of the unreinforced metal of the blades extending radially inboard). Exemplary airfoil securing includes friction welding, forge joining, coextrusion (e.g., followed by machining to further refine the airfoils and disk contours), diffusion bonding, hot isostatic pressing (HIP) bonding, and additive manufacturing (e.g., laser, electron beam, gas tungsten arc (GTA), and the like).

(21) One or more embodiments have been described. Nevertheless, it will be understood that various modifications may be made. For example, when implemented as a modification of a baseline engine configuration, details of the baseline may influence details of any particular implementation.

(22) Accordingly, other embodiments are within the scope of the following claims.