Impeller for aircraft engine

1. An impeller for a centrifugal compressor, the impeller rotatable about a central axis, comprising:

a front face and a rear face axially rearward of the front face, the rear face extending radially outwardly relative to the central axis from a bore of the impeller, the impeller having an inlet and an outlet downstream of the inlet, the impeller having a gaspath face extending from the inlet to the outlet;

an outer hub body including a first material and extending around the central axis, the outer hub body defining an entirety of the gaspath face, the gaspath face extending radially away from the central axis from the inlet to the outlet, an entirety of the rear face defined by the outer hub body;

blades protruding from the gaspath face and circumferentially distributed around the central axis; and

an inner hub body extending around the central axis, the inner hub body secured to the outer hub body, the outer hub body axially overlapping and extending around the inner hub body, the inner hub body made of a second material being more cold dwell resistant than the first material, the inner hub body located entirely radially inwardly of the gaspath face.

2. The impeller of claim 1 , wherein the first material is more creep resistant than the second material.

3. The impeller of claim 1 , wherein the first material is Ti-834.

4. The impeller of claim 3 , wherein the second material is Ti-6246.

5. The impeller of claim 1 , wherein the inner hub body defines the front face.

6. The impeller of claim 1 , wherein the inner hub body has an outer face facing an inner face of the outer hub body.

7. The impeller of claim 6 , comprising an annular gap between the outer face and the inner face.

8. The impeller of claim 7 , wherein the annular gap extends radially towards the central axis as the annular gap extends axially toward the outlet.

9. The impeller of claim 1 , wherein the outer hub body is secured to the inner hub body via at least two attachment locations being axially offset from one another.

10. The impeller of claim 9 , wherein the outer hub body is free of contact with the inner hub body between the at least two attachment locations.

11. The impeller of claim 10 , wherein the at least two attachment locations include a fore attachment location and a rear attachment location, the rear attachment location located radially inwardly from the fore attachment location.

12. The impeller of claim 10 , wherein the outer hub body is secured to the inner hub body via a front tongue-and-groove connection proximate a front face of the impeller and a rear tongue-and-groove connection proximate a rear face of the impeller.

13. An aircraft engine comprising:

a compressor having an impeller rotatable about a central axis, the impeller having an inlet and an outlet downstream of the inlet, the impeller having a gaspath face extending from the inlet to the outlet, the impeller having:

a front face and a rear face axially rearward of the front face, the rear face extending radially outwardly relative to a central axis from a bore of the impeller, the impeller having an inlet and an outlet downstream of the inlet, the impeller having a gaspath face extending from the inlet to the outlet;

an outer hub body including a first material and extending around the central axis, the outer hub body defining an entirety of the gaspath face, an entirety of the rear face defined by the outer hub body;

blades protruding from the gaspath face and circumferentially distributed around the central axis; and

an inner hub body extending around the central axis, the inner hub body secured to the outer hub body, the inner hub body contained within a recess defined by the outer hub body, the inner hub body made of a second material being more cold dwell resistant than the first material, the inner hub body having an outer face facing an inner face of the outer hub body, an annular gap between the outer face and the inner face, the inner hub body located entirely radially inwardly of the gaspath face.

14. The aircraft engine of claim 13 , wherein the first material is more creep resistant than the second material.

15. The aircraft engine of claim 13 , wherein the outer hub body is secured to the inner hub body via at least two attachment locations being axially offset from one another.

16. The aircraft engine of claim 15 , wherein the outer hub body is secured to the inner hub body via a front tongue-and-groove connection proximate the front face of the impeller and a rear tongue-and-groove connection proximate the rear face of the impeller.

17. The aircraft engine of claim 16 , wherein the first material is Ti-834 and wherein the second material is Ti-6246.