Additive layer repair of a metallic component

Abstract

A method of repairing a metallic component (formed from a first material) by powder feeding laser deposition, comprises the step of depositing a plurality of first repair layers onto a repair surface of the component to form a first repair zone, the first of the plurality of first repair layers comprising a mixture of A/B by weight of the first material and a second material, each nth successive one of the plurality of first repair layers comprising a change in the proportion of the second material in the mixture, the last of the plurality of first repair layers comprising a mixture of C/D by weight of the first material and the second material.

Claims

1. A method of repairing a metallic component by powder feeding laser deposition, the metallic component being formed from a first material, the method comprising depositing a plurality of first repair layers onto a repair surface of the component to form a first repair zone, the first of the plurality of first repair layers comprising a mixture of A/B by weight of the first material and a second material, each n.sup.th successive one of the plurality of first repair layers comprising a change in the proportion of the second material in the mixture, the last of the plurality of first repair layers comprising a mixture of C/D by weight of the first material and the second material, wherein the first material consists of at least one selected from the group consisting of a titanium alloy, a nickel alloy, a special steel and an aluminum alloy, the first material is provided as a powder having a first mean particle size, and the second material is provided as a powder having a second mean particle size, a distribution of the first mean particle size and the second mean particle size varies across the first repair zone in a thickness direction, if the first mean particle size is smaller than the second mean particle size, then, for the same volume of material, a time required to melt the first material will be less than a time required to melt the second material, and if the second mean particle size is smaller than the first mean particle size, then, for the same volume of material, the time required to melt the second material will be less than the time required to melt the first material.

2. The method as claimed in claim 1, wherein the integer n is in a range of 10 to 1,000.

3. The method as claimed in claim 1, wherein a ratio A/B is in a range of 80/20 to 5/95.

4. The method as claimed in claim 1, wherein a ratio C/D is in a range of 0/100 to 40/60.

5. The method as claimed in claim 1, wherein the change in the proportion of the second material in the mixture comprises an increase in the proportion of the second material in the mixture.

6. The method as claimed in claim 1, the method further comprising depositing a plurality of second repair layers of the second material onto the first repair zone to form a second repair zone.

7. The method as claimed in claim 6, the method further comprising depositing a plurality of third repair layers of a third material onto the second repair zone to form a third repair zone.

8. The method as claimed in claim 7, wherein the third material is metallurgically compatible with both the first material and the second material.

9. The method as claimed in claim 7, wherein if the second mean particle size is smaller than the third mean particle size, then, for the same volume of material, the time required to melt the second material will be less than the time required to melt the third material, and if the third mean particle size is smaller than the second mean particle size, then, for the same volume of material, the time required to melt the third material will be less than the time required to melt the second material.

10. The method as claimed in claim 1, wherein the first material and the second material have the same metallurgical composition.

11. A method of repairing a metallic component by powder feeding laser deposition, the metallic component being formed from a first material, the method comprising: depositing a plurality of second repair layers of a second material onto a repair surface of a first repair zone of the component to form a second repair zone; and depositing a plurality of third repair layers of a third material onto the second repair zone to form a third repair zone, wherein the first material consists of at least one selected from the group consisting of a titanium alloy, a nickel alloy, a special steel and an aluminum alloy, the first material is provided as a powder having a first mean particle size, and the second material is provided as a powder having a second mean particle size, a distribution of the first mean particle size and the second mean particle size varies across the first repair zone in a thickness direction, if the first mean particle size is smaller than the second mean particle size, then, for the same volume of material, a time required to melt the first material will be less than a time required to melt the second material, and if the second mean particle size is smaller than the first mean particle size, then, for the same volume of material, the time required to melt the second material will be less than the time required to melt the first material.

12. A metallic component comprising: a base region formed from a first material; and a first repair zone superposed on the base region, the first repair zone being formed from a plurality of first repair layers, the first of the plurality of first repair layers comprising a mixture of A/B by weight of the first material and a second material, each n.sup.th successive one of the plurality of first repair layers comprising a change in the proportion of the second material in the mixture, the last of the plurality of first repair layers comprising a mixture of C/D by weight of the first material and the second material, wherein the first material consists of at least one selected from the group consisting of a titanium alloy, a nickel alloy, a special steel and an aluminum alloy, the first material is provided as a powder having a first mean particle size, and the second material is provided as a powder having a second mean particle size, a distribution of the first mean particle size and the second mean particle size varies across the first repair zone in a thickness direction, if the first mean particle size is smaller than the second mean particle size, then, for the same volume of material, a time required to melt the first material will be less than a time required to melt the second material, and if the second mean particle size is smaller than the first mean particle size, then, for the same volume of material, the time required to melt the second material will be less than the time required to melt the first material.

13. The metallic component as claimed in claim 12, wherein the integer n is in a range of 10 to 1,000.

14. The metallic component as claimed in claim 12, wherein a ratio A/B is in a range of 80/20 to 5/95.

15. The metallic component as claimed in claim 12, wherein a ratio C/D is in a range of 0/100 to 40/60.

16. The metallic component as claimed in claim 12, wherein the change in the proportion of the second material in the mixture comprises an increase in the proportion of the second material in the mixture.

17. The metallic component as claimed in claim 12, further comprising a second repair zone superposed on the first repair zone, the second repair zone comprising a plurality of second repair layers of the second material.

18. The metallic component as claimed in claim 17, further comprising a third repair zone superposed on the second repair zone, the third repair zone comprising a plurality of third repair layers of a third material.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) There now follows a description of an embodiment of the disclosure, by way of non-limiting example, with reference being made to the accompanying drawings in which:

(2) FIG. 1 shows a schematic sectional view of a blown powder additive layer repair process according to the prior art;

(3) FIG. 2 shows a perspective view of a repaired metallic component according to a first embodiment of the disclosure;

(4) FIG. 3 shows a perspective view of an alternative arrangement of the repaired metallic component of FIG. 2;

(5) FIG. 4 shows a perspective view of a repaired metallic component according to a second embodiment of the disclosure;

(6) FIG. 5 shows a perspective view of a repaired metallic component according to a third embodiment of the disclosure;

(7) FIG. 6 shows a perspective view of a repaired metallic component according to a fourth embodiment of the disclosure;

(8) FIG. 7 shows a schematic sectional view of a blown powder additive layer repair process for implementing the method of the disclosure;

(9) FIG. 8 shows a schematic sectional view of an alternative blown powder additive layer repair process for implementing the method of the disclosure; and

(10) FIG. 9 shows a schematic sectional view of a gas turbine engine incorporating a repaired metallic component according to an embodiment of the disclosure.

(11) It is noted that the drawings may not be to scale. The drawings are intended to depict only typical aspects of the disclosure, and therefore should not be considered as limiting the scope of the disclosure. In the drawings, like numbering represents like elements between the drawings.

DETAILED DESCRIPTION

(12) The method of repairing a metallic component is described below with reference to the metallic component being a gas turbine engine compressor bladed disc.

(13) Referring to FIG. 2, a repaired metallic component that has been repaired according to a first embodiment of the disclosure is designated generally by the reference numeral 100.

(14) The metallic component 100 is formed from a first material 110 and has a first repair surface 120. In the present arrangement, the first material would typically be a titanium, nickel, special steel or aluminium alloy.

(15) In the method of the first embodiment of the disclosure, a powder feeding laser deposition technique is employed to deposit a plurality of first repair layers 130 onto the first repair surface 110. The plurality of the first repair layers 130 together forms a first repair zone 140.

(16) The first one of the plurality of first repair layers 130 is comprised of a mixture of A/B, by weight, of the first material 110 and a second material 150 respectively. In this first repair layer 130, the proportion A made up of the first material is 80% by weight, while the proportion B made up of the second material is 20% by weight.

(17) In the present arrangement, the second material 150 is typically a titanium, nickel, special steel or aluminium alloy

(18) In other arrangements, the composition of the first repair layer 130 may vary between 80% A and 20% B, and 5% A and 95% B.

(19) Each of the plurality of the first repair layers 130 is between approximately 100-1000 m in thickness, this being typical of the thickness of a layer of material produced by the powder feeding laser deposition technique.

(20) Each n.sup.th successive one of the plurality of first repair layers 130 comprises a change in the proportion of the second material 150 in the respective first repair layer 130. In the present embodiment of the method, the integer n is 10. In other words, at every 10.sup.th successive first repair layer the ratio of the first material 110 to the second material 150 changes. In the present embodiment, this change is a monotonic increase in the proportion of the second material 150 in the composition of the respective first repair layer 130.

(21) The first repair zone 140 thus comprises a graded composition that starts from 80% A and 20% B at the first of the first repair layers 130 and gradually changes, as outlined above, and finishes with the last of the first repair layers 130 having a composition of 0% A and 100% B.

(22) FIG. 3 shows a repaired metallic component that has been repaired according to a variant of the first embodiment of the disclosure. The repaired metallic component is again designated generally by the reference numeral 100.

(23) In this arrangement, the first repair zone 140 comprises a plurality of first repair layers 130. However, in this arrangement, the change in the proportion of the second material 150 in each of the first repair layers 130 is not always a monotonic increase in the proportion of the second material 150.

(24) In the example of FIG. 3, the proportion of the first repair layers 130 that is comprised of the second material 150 increases steadily from the first of the first repair layers 130 (i.e. at the first repair surface 120) through to a point mid-way through the thickness of the first repair zone 140.

(25) At this mid-way point, the proportion of the first repair layers 130 that is comprised of the second material 150 decreases steadily through to the last one of the first repair layers 130.

(26) Referring to FIG. 4, a repaired metallic component according to a second embodiment of the disclosure is designated generally by the reference numeral 200. Features of the repaired metallic component 200 which correspond to those of the repaired metallic component 100 have been given corresponding reference numerals for ease of reference.

(27) The repaired metallic component 200 comprises a plurality of first repair layers 130 that are deposited onto the repair surface 120 to form a first repair zone 140.

(28) This first repair zone 140 may comprise a monotonically graded change in composition of the first repair layers 130 through the thickness of the first repair zone 140, as outlined above in relation to the repaired metallic component 100.

(29) The repaired metallic component 200 further comprises a plurality of second repair layers 160 deposited onto the first repair zone 140 to form a second repair zone 170.

(30) In the embodiment of FIG. 4, each of the second repair layers 160 is composed only of the second material 150, such that the second repair zone 170 is formed entirely of the second material 150.

(31) Referring to FIG. 5, a repaired metallic component according to a third embodiment of the disclosure is designated generally by the reference numeral 300. Features of the repaired metallic component 300 which correspond to those of the repaired metallic component 100 have been given corresponding reference numerals for ease of reference.

(32) The repaired metallic component 300 comprises a plurality of first repair layers 130 that are deposited onto the repair surface 120 to form a first repair zone 140.

(33) This first repair zone 140 may comprise a monotonically graded change in composition of the first repair layers 130 through the thickness of the first repair zone 140, as outlined above in relation to the repaired metallic component 100.

(34) The repaired metallic component 300 further comprises a plurality of second repair layers 160 deposited onto the first repair zone 140 to form a second repair zone 170.

(35) The repaired metallic component 300 still further comprises a plurality of third repair layers 180 deposited onto the second repair zone 170 to form a third repair zone 205.

(36) In the embodiment of FIG. 5, each of the second repair layers 160 is composed only of the second material 150, such that the second repair zone 170 is formed entirely of the second material 150, and each of the third repair layers 180 is composed only of the third material 190, such that the third repair zone 205 is formed entirely of the third material 190.

(37) Referring to FIG. 6, a repaired metallic component according to a fourth embodiment of the disclosure is designated generally by the reference numeral 400. Features of the repaired metallic component 400 which correspond to those of the repaired metallic component 100 have been given corresponding reference numerals for ease of reference.

(38) The repaired metallic component 400 comprises a plurality of second repair layers 160 that are deposited onto the repair surface 120 to form a second repair zone 170.

(39) The repaired metallic component 400 further comprises a plurality of third repair layers 180 deposited onto the second repair zone 170 to form a third repair zone 205.

(40) In the embodiment of FIG. 6, each of the second repair layers 160 is composed only of the second material 150, such that the second repair zone 170 is formed entirely of the second material 150, and each of the third repair layers 180 is composed only of the third material 190, such that the third repair zone 205 is formed entirely of the third material 190.

(41) FIG. 7 shows a schematic arrangement of a modified powder feeding laser deposition process capable of performing the method of the present disclosure as outlined above in relation to the first and second embodiments of the disclosure.

(42) In the arrangement of FIG. 7, each of the first material 110 and the second material 150 is delivered to the deposition nozzle 310 via separate powder feeds 350, 360 respectively.

(43) The flow of powder through each powder feed 350,360 can be independently adjusted to change the powder composition slow 320 directed on to the layered build surface 330. This change in the powder composition is implemented automatically in the deposition programme operating code. The deposition software allows the method to vary the composition of the first repair layers 130 to achieve the graded layer composition as outlined above.

(44) The software may also use material data to compensate for different material densities and particle size distributions in order to maintain an accurate powder feed ratio in order to deliver the grading that is required.

(45) FIG. 8 shows a variant of the modified process shown in FIG. 7 that has been adapted to perform the method of the present disclosure as outlined above in relation to the third and fourth embodiments of the disclosure.

(46) FIG. 8 differs from FIG. 7 in the addition of another powder feed 470 (in addition to powder feeds 450 and 460) to deliver the third material 190.

(47) FIG. 9 shows a schematic sectional view of a turbofan engine 500. The turbofan gas turbine engine 500, as shown in FIG. 1, comprises in flow series an intake 511, a fan 512, an intermediate pressure compressor 513, a high pressure compressor 514, a combustion chamber 515, a high pressure turbine 516, an intermediate pressure turbine 517, a low pressure turbine 518 and an exhaust 519. The high pressure turbine 516 is arranged to drive the high pressure compressor 514 via a first shaft 526. The intermediate pressure turbine 517 is arranged to drive the intermediate pressure compressor 513 via a second shaft 528 and the low pressure turbine 518 is arranged to drive the fan 512 via a third shaft 530. In operation air flows into the intake 511 and is compressed by the fan 512. A first portion of the air flows through, and is compressed by, the intermediate pressure compressor 513 and the high pressure compressor 514 and is supplied to the combustion chamber 515. Fuel is injected into the combustion chamber 515 and is burnt in the air to produce hot exhaust gases which flow through, and drive, the high pressure turbine 516, the intermediate pressure turbine 517 and the low pressure turbine 518. The hot exhaust gases leaving the low pressure turbine 518 flow through the exhaust 519 to provide propulsive thrust. A second portion of the air bypasses the main engine to provide propulsive thrust.

(48) In the arrangement of FIG. 9, each of the stages of the intermediate pressure compressor 513 is formed as a bladed disc 520 that has been repaired according to a method of the present disclosure as outlined above.

(49) The foregoing description of various aspects of the disclosure has been presented for purposes of illustration and description. It is not intended to be exhaustive or to limit the disclosure to the precise form disclosed, and obviously, many modifications and variations are possible. Such modifications and variations that may be apparent to a person of skill in the art are included within the scope of the disclosure as defined by the accompanying claims.