BLADE OUTER AIR SEAL COMPONENT WITH VARYING THERMAL EXPANSION COEFFICIENT
An exemplary blade outer air seal component includes at least one first region of a first material, at least one second region of a second material, and at least one functionally graded transition region of the first material and the second material between a first region and a second region of the component. A thermal expansion coefficient of the first material is higher than a thermal expansion coefficient of the second material.
1 . A blade outer air seal component, comprising:
at least one first region of a first material;
at least one second region of a second material; and
at least one functionally graded transition region of the first material and the second material between a first region and a second region of the component, wherein a thermal expansion coefficient of the first material is higher than a thermal expansion coefficient of the second material.
2 . The component of claim 1 , wherein the first material is a metal.
3 . The component of claim 1 , wherein the second material is a ceramic or a ceramic matrix composite.
4 . The component of claim 1 , wherein the component is formed by a solid freeform (SFF) additive manufacturing process.
5 . The component of claim 4 , wherein the solid freeform (SFF) additive manufacturing process is selective laser melting (SLM).
6 . The component of claim 1 , wherein the first region is radially outside the second region.
7 . The component of claim 6 , wherein the first region provides an attachment structure that secures the composite blade outer air seal to a casing.
8 . The component of claim 7 , wherein the second region provides a blade interface surface that interfaces with a blade tip.
9 . The component of claim 2 , wherein the metal is selected from the group consisting of nickel base, iron base, cobalt base superalloy, titanium, and titanium alloy.
10 . The component of claim 3 , wherein the ceramic is selected from the group consisting of silicon carbide, silicon nitride, silicon oxynitride, and aluminum oxide.
11 . The component of claim 3 , wherein the ceramic matrix composite is selected from the group consisting of SiC/SiC, C/SiC, and SiC/Si.
12 . A method of forming a blade outer air seal containing separate regions of different materials comprising:
forming at least one first region of a first material;
forming a graded transition region on the first region with composition of the transition region changing from a first material to a second material as the forming of the transition region progresses; and
forming a second region of a second material on the transition region, wherein a thermal expansion coefficient of the first material is higher than a thermal expansion coefficient of the second material.
13 . The method of claim 12 , wherein the first material is a metal.
14 . The method of claim 12 , wherein the second material is a ceramic or ceramic matrix composite.
15 . The method of claim 12 , wherein forming comprises solid freeform (SFF) additive manufacturing.
16 . The method of claim 15 , wherein additive manufacturing comprises direct laser melting.
17 . The method of claim 13 , where the metal is selected from a group consisting of nickel base, iron base and cobalt base superalloy, titanium and titanium alloy.
18 . The method of claim 14 , wherein the ceramic is selected from the group consisting of silicon carbide, silicon nitride, silicon oxynitride, and aluminum oxide.
19 . The method of claim 14 , wherein the ceramic matrix composite is selected from the group consisting of SiC/SiC, C/SiC, and SiC/Si.
20 . The method of claim 12 , further comprising holding the composite blade outer air seal using an attachment structure provided by a portion of the first region, and interfacing with a blade tip with a surface of the second region.