Patent Application
20200001368
Exemplary embodiments of the present disclosure relate generally to fabrication of composite metallic components and, in one embodiment, to methods of fabricating composite cast and sintered metallic components.
Various manufacturing methods and material systems have different advantages and drawbacks. Therefore, it may be advantageous to combine different manufacturing methods and material systems together in order to create composite components that enable synergistic benefits or to overcome the specific limitations of a single technology.
For example, a single crystal nickel-based super alloy casting exhibits superior material properties for high temperature creep resistance, but it may be difficult to cast certain geometries in a single crystal alloy without increasing manufacturing expenditures due to increased tooling costs or issues such as recrystallization certain geometry. Similarly, geometry changes to a component with an already manufactured tool set can be expensive as they will often require complete new tooling. Likewise, components made from sintered powdered metals can be much less expensive to produce, allow for a wider range of geometric designs, but generally have less robust material properties.
According to an aspect of the disclosure, a method of fabricating a composite component is provided. The method includes manufacturing a cast metallic component including a surface and defining an attachment point along the surface, placing a fugitive mold defining an element feature against the surface such that the element feature aligns with the attachment point, filling the element feature with powdered metallic material and heating the cast metallic component and the powdered metallic material to a temperature above a sintering temperature of the powdered metallic material and below a melting temperature of the cast metallic component.
In accordance with additional or alternative embodiments, the attachment point has undercut features and the undercut features include one or more of dovetails, zig-zags, spirals, curves and multi-directional extrusions.
In accordance with additional or alternative embodiments, the cast metallic component includes a fastening element for fastening a sintered element to the cast metallic component at the attachment point.
In accordance with additional or alternative embodiments, the element feature includes an opening with protruding undercuts.
In accordance with additional or alternative embodiments, the method further includes continuing the heating until the powdered metallic material is cured into an element attached to the surface at the attachment point and removing a remainder of the fugitive mold following the heating.
In accordance with additional or alternative embodiments, the heating results in up to 15% shrinkage of the element from a volume of the powdered metallic material at the attachment point.
In accordance with additional or alternative embodiments, the method further includes designing the attachment point such that the element tightens onto the cast metallic component during the heating.
In accordance with additional or alternative embodiments, the attachment point is designed such that the element has a tooth-root shape.
According to another aspect of the disclosure, a method of fabricating a composite component is provided and includes manufacturing a cast metallic component including a surface and defining dovetail-shaped attachment points along the surface, placing a fugitive mold defining openings with protruding undercuts against the surface such that each opening aligns with a corresponding one of the dovetail-shaped attachment points, filling the openings with powdered metallic material and heating the cast metallic component and the powdered metallic material to a temperature above a sintering temperature of the powdered metallic material and below a melting temperature of the cast metallic component.
In accordance with additional or alternative embodiments, each dovetail-shaped attachment point includes a neck section proximate to an uppermost portion of the surface and a tapered section having an increasing width with increasing depth from the neck section and each opening has a diameter which corresponds to a diameter of the neck section of the corresponding one of the dovetail-shaped attachment points.
In accordance with additional or alternative embodiments, each opening is corrugated.
In accordance with additional or alternative embodiments, the cast metallic component includes one or more fastening elements for fastening one or more sintered elements to the cast metallic component at one or more of the attachment points.
In accordance with additional or alternative embodiments, the method further includes continuing the heating until the powdered metallic material is cured into elements attached to the surface at each of the attachment points and removing a remainder of the fugitive mold following the heating.
In accordance with additional or alternative embodiments, the heating results in up to 15% shrinkage of the elements from a volume of the powdered metallic material at each of the attachment points.
In accordance with additional or alternative embodiments, the method further includes designing the attachment points such that each of the elements tighten onto the cast metallic component during the heating.
In accordance with additional or alternative embodiments, the attachment points are designed such that the elements have tooth-root shape.
According to yet another aspect of the disclosure, a composite component is provided and includes a cast metallic component including a surface and defining attachment points along the surface, elements of sintered powdered metallic material respectively comprising first and second parts, the first parts being respectively secured in a corresponding one of the attachment points, the second parts extending outwardly from corresponding ones of the first parts to protrude from the surface and the first and second parts cooperatively forming a tooth-root shape.
In accordance with additional or alternative embodiments, the attachment points each include attachment features that extend into the cast metallic component curvi-linearly outwardly and the first parts of each of the elements include sintered attachment protrusions that extend into the cast metallic component curvi-linearly outwardly.
In accordance with additional or alternative embodiments, the second parts of each of the elements are corrugated.
In accordance with additional or alternative embodiments, each of the first parts has a lesser volume than the corresponding one of the attachment points.
These and other advantages and features will become more apparent from the following description taken in conjunction with the drawings.
The following descriptions should not be considered limiting in any way. With reference to the accompanying drawings, like elements are numbered alike:
These and other advantages and features will become more apparent from the following description taken in conjunction with the drawings.
A detailed description of one or more embodiments of the disclosed apparatus and method are presented herein by way of exemplification and not limitation with reference to the Figures.
As will be described below, a fabrication method is provided in which composite components that have a robust structure are formed by cast metal and detailed complex features are formed by powdered metal.
With reference to
As shown in
With reference to
Next, as shown in
Once the one or more fugitive molds 20 are placed against the surface 11, the openings 21 are filled with powdered metallic materials as shown in
As shown in
Each sintered element 30 has a cross-sectional shape which mimics the cross-sectional shapes of the attachment point 12 and the opening 21 it is formed in. Thus, each sintered element 30 has a first part 31 and a second part 32. The first part 31 is formed within the neck portion 120 and the tapered portion 121 of the corresponding attachment point 12. The second part 32 is integrally coupled to the first part 31 and extends from the first part 31 to protrude outwardly from the surface 11. In an event the corresponding attachment point 12 has a dovetail-shape and the corresponding opening 21 is corrugated, the first part 31 will have a corresponding dovetail-shape 310 and the second part 32 will have a corresponding corrugated shape 320.
In accordance with embodiments, a final volume of each of the sintered elements 30 may be reduced from an initial volume of the powdered metallic material of the corresponding attachment point 12 and the corresponding opening 21. This volume reduction is a consequence of the curing process and may result in up to 15% reduction in volume. This can be seen in
To the extent that the volume reduction or shrinkage illustrated in
With reference to
That is, as shown in
In particular, the attachment features 701 may extend into the cast metallic component 10 curvi-linearly outwardly such that the resulting sintered attachment protrusions 702 similarly extend into the cast metallic component 10 curvi-linearly. The attachment features 701 a taper away from each other with increasing depth into the cast metallic component 10 and the sintered attachment protrusions 702 similarly taper away from each other with increasing depth into the cast metallic component 10. Each attachment feature 701 and each corresponding sintered attachment protrusion 702 can have a substantially similar radius of outward curvature. Outer surfaces 7021 of the sintered attachment protrusions 702 may be nearly aligned in a radial dimension with an exterior surface 321 of the second part 32 and inner surfaces 7022 of the sintered attachment protrusions 702 may be separated from one another by a radial distance DR. The first and second parts 31 and 32 of the given sintered element 30 thus cooperatively form a tooth-root shaped element 710.
With reference to
Benefits of the features described herein are the provision for production of a composite component that takes advantage of the beneficial properties of different manufacturing techniques and material systems. The fabrication methods can rely on a cast substrate for structural and creep resistance purposes and can use powdered metal features to create additional surface area or detailed geometry that could not be achievable with cast metal due to recrystallization, tooling costs or other limitations. Additionally, tooling costs for a fugitive mold is significantly less than for a traditional wax pattern tool set. This allows for multiple different fugitive molds to be used on a single substrate thereby allowing numerous and varying designs to be produced and tested while requiring less tooling cost and time as compared to having to use different traditional tool sets. This can in turn allow for multiple complex designs to be built and tested for less cost than a single complex design, which is fabricated using conventional techniques and can result in faster innovations and a more valuable final product.
The term “about” is intended to include the degree of error associated with measurement of the particular quantity based upon the equipment available at the time of filing the application.
The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the present disclosure. As used herein, the singular forms “a”, “an” and “the” are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms “comprises” and/or “comprising,” when used in this specification, specify the presence of stated features, integers, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, element components, and/or groups thereof.
While the present disclosure has been described with reference to an exemplary embodiment or embodiments, it will be understood by those skilled in the art that various changes may be made and equivalents may be substituted for elements thereof without departing from the scope of the present disclosure. In addition, many modifications may be made to adapt a particular situation or material to the teachings of the present disclosure without departing from the essential scope thereof. Therefore, it is intended that the present disclosure not be limited to the particular embodiment disclosed as the best mode contemplated for carrying out this present disclosure, but that the present disclosure will include all embodiments falling within the scope of the claims.
