Method of surface-treating a cast intermetallic component

Patent metadata

Field	Value
Publication number	US-2016201181-A1
Application number	US-201514966237-A
Country	US
Kind code	A1
Filing date	Dec 11, 2015
Priority date	Jan 9, 2015
Publication date	Jul 14, 2016
Grant date	—

Abstract

There is proposed a method of surface-treating a cast intermetallic component, which is intended primarily to reduce or remove surface porosity from the component. The method includes the steps of: providing a cast intermetallic component; placing the component in an inert atmosphere; focussing a laser beam on a surface of the component; traversing the laser beam over at least a region of said surface whilst the component is in said inert atmosphere; and controlling the laser beam during said traversing step so as to locally melt the intermetallic material of the component to a depth of no more than 300 μm, as measured from said surface of the component.

First claim

1 . A method of surface-treating a cast intermetallic component, the method comprising the steps of: providing a cast intermetallic component; placing the component in an inert atmosphere; focussing a laser beam on a surface of the component; traversing the laser beam over at least a region of said surface whilst the component is in said inert atmosphere; and controlling the laser beam during said traversing step so as to locally melt the intermetallic material of the component to a depth of no more than 300 μm, as measured from said surface of the component, the method further including a step of analysing the component, prior to said steps of focussing and traversing the laser beam, in order to identify target surface-connected and/or near-surface pores in the component and determining the maximum depth of said target pores from the surface of the component; wherein said step of controlling the laser beam involves operating the laser beam so as to locally melt the intermetallic material of the component to said maximum depth.

2 . A method according to claim 1 , wherein the laser beam is controlled so as to locally melt the intermetallic material of the component to a depth of no more than 150 μm as measured from said surface of the component.

3 . A method according to claim 1 , wherein said step of analysing the component involves capturing an image of the surface region of the component.

4 . A method according to claim 3 , wherein said image comprises a stereo-optical image.

5 . A method according to claim 3 , wherein said image comprises an X-ray image.

6 . A method according to claim 3 , wherein said step of controlling the laser beam involves controlling the laser beam in dependence on features of said image.

7 . A method according to claim 3 , wherein said step of analysing the component is performed manually.

8 . A method according to claim 3 , wherein said step of analysing the component is performed automatically using a computer.

9 . A method according to claim 1 , wherein said focussing step involves focussing the laser beam such that it energizes a target area on the surface of the component, and wherein said step of traversing involves moving the laser beam incrementally relative to the component so as to energize successive said target areas on the surface of the component; each target area being energized for a discrete dwell period and overlapping at least the immediately preceding target area.

10 . A method according to claim 1 , wherein said step of traversing involves movement of the laser beam.

11 . A method according to claim 1 , wherein said step of traversing involves movement of the component.

12 . A method according to claim 1 , wherein a heat load is applied to said component during said focussing, traversing and controlling steps, said heat load being applied to the opposite side of the component to that on which said surface is provided.

13 . A method according to claim 1 , wherein said component is pre-tensioned during said focussing, traversing and controlling steps.

14 . A method according to claim 1 , wherein said step of controlling the laser beam involves controlling at least one of: the power; the focus; the beam-shape; and the pulse period of the laser beam.

15 . A method according to claim 1 , performed on a component which is formed of intermetallic titanium.

16 . A method according to claim 1 , performed on a component which is formed of gamma titanium aluminide.

17 . A method according to claim 1 , performed on a component in the form of a turbine blade for a gas turbine engine.

18 . A method according to claim 1 , wherein said step of placing the component in an inert atmosphere involves placing the component in a vacuum chamber.

19 . A method according to claim 1 , involving the use of a plurality of said laser beams.

20 . A method according to claim 1 , performed simultaneously on a plurality of said components.

21 . A method according to claim 1 , further comprising hot isostatic pressing the component after the steps of focussing and traversing the laser beam.

22 . A method of surface-treating a cast intermetallic component, the method comprising the steps of: providing a cast intermetallic component; placing the component in an inert atmosphere; focussing a laser beam on a surface of the component; traversing the laser beam over at least a region of said surface whilst the component is in said inert atmosphere; controlling the laser beam during said traversing step so as to locally melt the intermetallic material of the component to a depth of no more than 300 μm, as measured from said surface of the component, and hot isostatic pressing the component, the method further including a step of analysing the component, prior to said steps of focussing and traversing the laser beam, in order to identify target surface-connected and/or near-surface pores in the component and determining the maximum depth of said target pores from the surface of the component; wherein said step of controlling the laser beam involves operating the laser beam so as to locally melt the intermetallic material of the component to said maximum depth, the step of analysing the component involves capturing an image of the surface region of the component and the image is selected from the group consisting of a stereo-optical image, an X-ray image and a combination of a stereo-optical image and an X-ray image.

Assignees

• Rolls Royce Plc

Inventors

• Tuppen Stephen John
• Clark Daniel

Classifications

• C21D1/34

  Methods of heating (C21D1/06 takes precedence) · CPC title

• F05D2230/90

  Coating; Surface treatment · CPC title

• B23K26/0006

  taking account of the properties of the material involved (B23K26/32, B23K26/40 take precedence) · CPC title

• B23K2103/10

  Aluminium or alloys thereof · CPC title

• C22F1/183 Primary

  of titanium or alloys based thereon · CPC title