WO2019040795A1

WO2019040795A1 - Additively manufactured parts having varied grain microstructures and related methods of making the same

Info

Publication number: WO2019040795A1
Application number: PCT/US2018/047824
Authority: WO
Inventors: John Siemon; Neville Whittle; Kyle Williams
Original assignee: Arconic Inc.
Priority date: 2017-08-23
Filing date: 2018-08-23
Publication date: 2019-02-28

Abstract

One or more embodiments of the present disclosure are directed towards methods of modifying additively manufactured microstructures including friction stir modification (FSM) processing of directed energy deposition (DED) additively manufactured (AM) build or AM part, such that via the FSM process, the grain structure is modified from a columnar structure to an equiaxed structure.

Description

Additively Manufactured Parts Having Varied Grain Microstructures and

Related Methods of Making the Same

CROSS-REFERENCE TO RELATED APPLICATION

[0001] This application claims benefit of U.S. provisional patent application Ser. No. 62/549,220 filed August 23, 2017, which is herein incorporated by reference.

FIELD OF THE INVENTION

[0002] Broadly, the present disclosure is directed towards methods of modifying solidified additively manufactured microstructures. More specifically, the present disclosure is directed towards methods including friction stir modification (FSM) processing of at least some regions, or portions of regions, of an additively manufactured (AM) build or AM part, such that via the FSM process, the grain structure of at least one layer of the AM build in the FSM processed region is modified from a columnar structure to an equiaxed structure.

BACKGROUND

[0003] Additively manufactured (AM) builds that are made from metallic AM feed stock materials via directed energy deposition (DED) additive manufacturing methods have columnar structures. Metallic parts or components having columnar structures can be disadvantageous for many end use applications.

SUMMARY OF THE INVENTION

[0004] Accordingly, in some embodiments, the present disclosure provides methods for breaking up and refining columnar structures in a solidified AM build or AM part.

[0005] In one embodiment, a method is provided, comprising: additively manufacturing at least one layer of an AM build, wherein at least a portion of the AM build includes a metallic AM feedstock, and wherein the at least one AM build layer includes a first grain microstructure; directing a friction stir modification (FSM) tool over at least a portion of a surface of the AM build layer to provide friction stir modification compressive stresses, mechanical stirring forces, or a combination thereof to the AM build layer in a region of the AM build; wherein the friction stir modification tool is configured to transform the first grain microstructure into a second grain microstructure, wherein the first grain microstructure is a columnar structure and the second grain microstructure is an equiaxed structure.

[0006] In one or more of the aforementioned embodiments, the method comprises directing an FSM tool over an entire surface of an AM bead deposition.

[0007] In one or more of the aforementioned embodiments, the method comprises directing an FSM tool over at least a portion of an AM bead deposition.

[0008] In one or more of the aforementioned embodiments, the method comprises directing an FSM tool iteratively over at least a portion of an AM bead deposition.

[0009] In one or more of the aforementioned embodiments, the method comprises directing an FSM tool over a portion of the surface of the AM build.

[00010] In one or more of the aforementioned embodiments, the method comprises directing an FSM tool over an entire surface of the AM build.

[00011] In one or more of the aforementioned embodiments, the method comprises directing the FSM tool over at least a portion of each sequential AM build layer, such that the cross-sectional microstructure for a given region of the AM build layer varies from the columnar structure to the equiaxed structure.

[00012] In one or more of the aforementioned embodiments, the method comprises directing the FSM tool over at least a portion of each sequential AM build layer, such that the cross-sectional microstructure for a given region of the AM build layer is the columnar structure, and an adjacent cross-sectional microstructure is the equiaxed structure.

[00013] In one or more of the aforementioned embodiments, friction stir processing, via the FSM tool, is completed in-situ, during directed energy deposition additive manufacturing.

[00014] In one or more of the aforementioned embodiments, the FSM tool is utilized on every AM bead in an AM build, such that the corresponding microstructure of each AM build layer is transformed from the columnar structure to the equiaxed structure.

[00015] In one or more of the aforementioned embodiments, the FSM tool is utilized in regions of every AM bead in an AM build or part.

[00016] In one or more of the aforementioned embodiments, the FSM tool is utilized in alternating layers, of an AM build.

[00017] In one or more of the aforementioned embodiments, the FSM tool is utilized in alternating AM bead deposition in an AM build.

[00018] In one or more of the aforementioned embodiments, the FSM tool is utilized in layers of an AM build at irregular intervals.

[00019] In one or more of the aforementioned embodiments, the first grain microstructure realizes a first average grain size, and wherein the second grain microstructure realizes a second average grain size.

[00020] In one or more of the aforementioned embodiments, the second average grain size is less than the first average grain size.

[00021] In one or more of the aforementioned embodiments, the second average grain size is not greater than 95% of the first average grain size, or is not greater than 90% of the first average grain size, or is not greater than 80% of the first average grain size, or is not greater than 70% of the first average grain size, or is not greater than 60% of the first average grain size, or is not greater than 50% of the first average grain size, or is not greater than 40% of the first average grain size.

[00022] In one or more of the aforementioned embodiments, the directing the friction stir modification (FSM) tool is a first directing step, and wherein the method comprises a second directing step; wherein the second directing step comprises transforming the second grain microstructure to a third grain microstructure.

[00023] In one or more of the aforementioned embodiments, the third grain microstructure realizes a third average grain size, wherein the third average grain size is less than the second average grain size.

[00024] In one or more of the aforementioned embodiments, the AM build is a titanium alloy.

[00025] In one or more of the aforementioned embodiments, the AM build is a titanium aluminide alloy.

[00026] In one or more of the aforementioned embodiments, the AM build is an aluminum alloy.

[00027] In one or more of the aforementioned embodiments, the AM build is a steel alloy.

[00028] In one or more of the aforementioned embodiments, the AM build is a nickel alloy.

[00029] In one or more of the aforementioned embodiments, the AM build is an aerospace component.

[00030] In one or more of the aforementioned embodiments, the AM build is an automotive component.

[00031] In one or more of the aforementioned embodiments, the AM build is a turbine component. [00032] In one or more of the aforementioned embodiments, the AM build is a consumer product component.

[00033] In one or more of the aforementioned embodiments, the FSM tool comprises one of: a straight, polygonal pin; a straight, cylindrical pin; a straight, square pin; or a straight, triangular pin.

[00034] In one or more of the aforementioned embodiments, the FSM tool is configured with one of: a threaded, polygonal pin; a threaded, cylindrical pin; a threaded, square pin; or a threaded, triangular pin

[00035] In one or more of the aforementioned embodiments, the FSM tool is configured with one of: a tapered, polygonal pin; a tapered, cylindrical pin; a tapered, square pin; or a tapered, triangular pin.

[00036] These and other aspects, advantages, and novel features of the invention are set forth in part in the description that follows and will become apparent to those skilled in the art upon examination of the following description and figures, or may be learned by practicing the invention.

BRIEF DESCRIPTION OF THE DRAWINGS

[00037] Figure 1 depicts a schematic illustration of an embodiment of the present disclosure, including a directed energy deposition combined with friction stir modification tooling, in accordance with the instant disclosure.

[00038] Figure 2 depicts a close-up perspective view of another embodiment of the instant disclosure, depicting a partial view of the friction stir modification tooling, in accordance with some embodiments of the instant disclosure. [00039] Figure 3a-3e depicts several embodiments of the pin geometry of the FSM tool, in accordance with the instant disclosure.

[00040] Figure 4 depicts an embodiment of a directed energy deposition (powder feed) additive manufacturing machine and corresponding process, in accordance with the instant disclosure.

[00041] Figure 5 depicts an embodiment of a directed energy deposition (wire feed) additive manufacturing machine and corresponding process, in accordance with the instant disclosure.

[00042] Figure 6A-6C depicts several schematic embodiments of cut-away side views of an AM part or AM build manufactured in accordance with one or more methods of the present disclosure.

[00043] Figure 7 is a schematic embodiment of a cut-away side view of an AM build or AM part manufactured by one or more methods of the present disclosure.

[00044] Figure 8 is a schematic embodiment of a cut-away side view of an AM build or AM part manufactured by one or more methods of the present disclosure.

[00045] Figure 9 is a schematic embodiment of a cut-away side view of an AM build or AM part manufactured by one or more methods of the present disclosure.

[00046] Figure 10 is a schematic embodiment of a cut-away side view of an AM build or AM part manufactured by one or more methods of the present disclosure.

[00047] Figure 11 is a schematic embodiment of a cut-away side view of an AM build or AM part manufactured by one or more methods of the present disclosure.

DESCRIPTION

[00048] The various embodiments to the present disclosure will be further explained regarding the attached drawings, wherein like structures are referred to by like numerals throughout the several views. The drawings shown are not necessarily to scale, with emphasis instead generally being placed upon illustrating the principles of the present invention. Further, some features may be exaggerated to show details of particular components.

[00049] In addition, any measurements, specifications and the like shown in the figures are intended to be illustrative, and not restrictive. Therefore, specific structural and functional details disclosed herein are not to be interpreted as limiting, but merely as a representative basis for teaching one skilled in the art to variously employ the present invention.

[00050] Among those benefits and improvements that have been disclosed, other objects and advantages of this invention will become apparent from the following description taken in conjunction with the accompanying figures. Detailed embodiments of the present invention are disclosed herein; however, it is to be understood that the disclosed embodiments are merely illustrative of the invention that may be embodied in various forms. In addition, each of the examples given about the various embodiments of the invention is intended to be illustrative, and not restrictive.

[00051] Throughout the specification and claims, the following terms take the meanings explicitly associated herein, unless the context clearly dictates otherwise. The phrases "in one embodiment" and "in some embodiments" as used herein do not necessarily refer to the same embodiment s), though it may. Furthermore, the phrases "in another embodiment" and "in some other embodiments" as used herein do not necessarily refer to a different embodiment, although it may. Thus, as described below, various embodiments of the invention may be readily combined, without departing from the scope or spirit of the invention.

[00052] In addition, as used herein, the term "or" is an inclusive "or" operator, and is equivalent to the term "and/or," unless the context clearly dictates otherwise. The term "based on" is not exclusive and allows for being based on additional factors not described, unless the context clearly dictates otherwise. In addition, throughout the specification, the meaning of "a," "an," and "the" include plural references. The meaning of "in" includes "in" and "on".

[00053] As used herein, "additive manufacturing" means: "a process of joining materials to make objects from 3D model data, usually layer upon layer, as opposed to subtractive manufacturing methodologies", as defined in ASTM F2792-12a entitled "Standard Terminology for Additively Manufacturing Technologies".

[00054] As used herein, "additive systems" means machines and related instrumentation used for additive manufacturing.

[00055] As used herein, "directed energy deposition" means an additive manufacturing process in which focused thermal energy is used to fuse materials by melting as they are being deposited as defined by ASTM F2792-12A.

[00056] As used herein, "grain" takes on the meaning defined in ASTM El 12 §3.2.2, i.e., "the area within the confines of the original (primary) boundary observed on the two-dimensional plane of-polish or that volume enclosed by the original (primary) boundary in the three- dimensional object". In one embodiment, "grain microstructure" means: the fine structure (in a metal or other material) that can be made visible and examined with a microscope. Without being bound by a particular mechanism or theory, it is believed that the microstructure of a material (such as metals, metal alloys, ceramics, and/or composites) can strongly influence physical properties (e.g. strength, toughness, ductility, hardness, corrosion resistance, high/low temperature behavior or wear resistance) of the material and ultimately whether the component or part is acceptable for its end use applications. Some non-limiting examples of microstructure include columnar and equiaxed structures. [00057] As used herein, "columnar structure" means a grain microstructure predominately comprising columnar grains. A columnar structure may be characterized by the visual observation of structures having an aspect ratio resembling, or characterized by, pillared or column-type architecture. In one embodiment, a columnar structure comprises at least 60% columnar grains. In another embodiment, a columnar structure comprises at least 75% columnar grains. In yet another embodiment, a columnar structure comprises at least 90% columnar grains. In another embodiment, a columnar structure comprises at least 95% columnar grains. In yet another embodiment, a columnar structure comprises at least 99% columnar grains.

[00058] "Columnar grains" generally have an average aspect ratio of at least 4: 1 as measured in the YZ and/or XZ planes, wherein the Z plane is the build direction. The "aspect ratio" is determined using commercial software Edax OIM version 8.0 or equivalent. The commercial software fits an ellipse to the perimeter points of the grain. In one embodiment, columnar grains have an average aspect ratio of at least 5: 1. In another embodiment, columnar grains have an average aspect ratio of at least 6: 1. In yet another embodiment, columnar grains have an average aspect ratio of at least 7: 1. In another embodiment, columnar grains have an average aspect ratio of at least 8: 1. In yet another embodiment, columnar grains have an average aspect ratio of at least 9: 1. In another embodiment, columnar grains have an average aspect ratio of at least 10: 1. The amount (volume percent) of columnar grains in a product may be determined by EBSD (electron backscatter diffraction) analysis of a suitable number of SEM micrographs of the product. Generally, at least 5 micrographs should be analyzed. The products may be analyzed in an as-built condition, or in a condition realized after subsequent post-processing (e.g., thermal treatments and/or working) [00059] As used herein, "equiaxed structure" means a grain microstructure predominately comprising equiaxed grains. In one embodiment, an equiaxed structure comprises at least 60% equiaxed grains. In another embodiment, an equiaxed structure comprises at least 75% equiaxed grains. In yet another embodiment, an equiaxed structure comprises at least 90% equiaxed grains. In another embodiment, an equiaxed structure comprises at least 95% equiaxed grains. In yet another embodiment, an equiaxed structure comprises at least 99% equiaxed grains.

[00060] "Equiaxed grains" generally have an average aspect ratio of less than 4: 1 as measured in the XY, YZ, and XZ planes. In one embodiment, "equiaxed" means grains in a microstructure that have axes of approximately the same length. The "aspect ratio" is determined using commercial software Edax OIM version 8.0 or equivalent. The commercial software fits an ellipse to the perimeter points of the grain. As used herein, "aspect ratio" is the inverse of: the length of the minor axis of the ellipse divided by the length of the major axis of the ellipse as determined using commercial software. In one embodiment, equiaxed grains have an average aspect ratio of not greater than 4: 1. In another embodiment, equiaxed grains have an average aspect ratio of not greater than 3 : 1. In yet another embodiment, equiaxed grains have an average aspect ratio of not greater than 2: 1. In another embodiment, equiaxed grains have an average aspect ratio of not greater than 1.5: 1. In yet another embodiment, equiaxed grains have an average aspect ratio of not greater than 1.1 : 1. The amount (volume percent) of equiaxed grains in a product may be determined by EBSD (electron backscatter diffraction) analysis of a suitable number of SEM micrographs of the product. Generally, at least 5 micrographs should be analyzed. The products may be analyzed in an as-built condition, or in a condition realized after subsequent post-processing (e.g., thermal treatments and/or working) [00061] As used herein: "directed energy deposition" (DED) means: an additive manufacturing process in which focused thermal energy is used to fuse materials by melting as they are being deposited. As used herein with respect to additive manufacturing, the directed energy deposition AM method can utilize powder or wire as an additive manufacturing feedstock/feed material.

[00062] As used herein, "energy source" means: the energy course configured for transforming an additive manufacturing feed material or feedstock into an AM build. Some non-limiting examples of focused thermal energy sources include a laser beam, an electron beam, a plasma arc source, and/or combinations thereof. One or more energy sources may be used during an additive manufacturing process.

[00063] As used herein, "FSM tooling" means: a rotating tool that is configured to contact at least a portion of the surface of the AM build. In some embodiments, the tool is non-consumable (e.g. can be used in the tooling process multiple times) As a non-limiting example, the FSM tool is configured to work in conjunction with the AM energy source such that the FSM tool follows the path of the AM feedstock deposition. In this embodiment, the FSM tool is configured to work on rapidly solidified (e.g. non-molten) AM depositions, such that the FSM tool is configured to modify the grain structure of the heated region of the AM build. In some embodiments, the FSM tool is configured to modify the grain structure of the heated region of the AM build via a pin (as further described below with respect to the FSM tool) projecting into AM build. In some embodiments, the FSM tool is configured to modify the grain structure of the heated region of the AM build via frictional engagement with a surface of the AM build.

[00064] As depicted, a directed energy deposition additive manufacturing process is configured to deposit an AM feedstock material 102 onto a substrate 104 (e.g. AM build) via a directed energy 106 (e.g. laser) deposition process to provide an AM bead (and/or AM build layer) on the substrate (and/or AM build). In some embodiments, the directed energy deposition additive manufacturing process is performed in a LENS machine produced by Optomec of Albuquerque, NM.

[00065] Figure 1 depicts a partial view of an embodiment of a friction stir modification tool (FSM tool) in accordance with some embodiments of the present disclosure. As depicted in Figure 1, the FSM tool 110 has a pin 108 which at least partially extends into the depth of the AM bead 112 (e.g. as depicted, in a single build layer). While inserted onto the cooled (e.g. non-molten), deposited AM region in the AM bead and/or build layer, the FSM tool is rotating and moving in a direction that corresponds to the direction of the AM machine and deposition pathway. With the embodiment of FSM combined (e.g. in-situ) with AM via directed energy deposition (e.g. LENS), the as-deposited microstructure is modified from a first grain microstructure (i.e. a columnar structure) to a second grain microstructure (i.e. an equiaxed structure) (e.g. at least in the region where the FSM tool interacted with the AM build and/or the immediately adjacent regions to the FSM contact region on the AM build surface). In some embodiments, the as- deposited microstructure is modified from a columnar structure to a generally equiaxed structure, (e.g. a structure having at least 50% equiaxed grains and less than 60% equiaxed grains).

[00066] In some embodiments, the FSM tool is rotating at least at 50 revolutions per minute (RPM). In some embodiments, the FSM tool is rotating at least at 100 RPM. In some embodiments, the FSM tool is rotating at least at 150 RPM. In some embodiments, the FSM tool is rotating at least at 200 RPM. In some embodiments, the FSM tool is rotating at least at 250 RPM. In some embodiments, the FSM tool is rotating at least at 300 RPM. In some embodiments, the FSM tool is rotating at least at 350 RPM. In some embodiments, the FSM tool is rotating at least at 400 RPM. In some embodiments, the FSM tool is rotating at least at 450 RPM. In some embodiments, the FSM tool is rotating at least at 500 RPM. In some embodiments, the FSM tool is rotating at least at 550 RPM. In some embodiments, the FSM tool is rotating at least at 600 RPM. In some embodiments, the FSM tool is rotating at least at 650 RPM. In some embodiments, the FSM tool is rotating at least at 700 RPM. In some embodiments, the FSM tool is rotating at least at 750 RPM.

[00067] In some embodiments, the FSM tool is rotating at not greater than 750 revolutions per minute (RPM). In some embodiments, the FSM tool is rotating at not greater than 700 RPM. In some embodiments, the FSM tool is rotating at not greater than 650 RPM. In some embodiments, the FSM tool is rotating at not greater than 600 RPM. In some embodiments, the FSM tool is rotating at not greater than 550 RPM. In some embodiments, the FSM tool is rotating at not greater than 500 RPM. In some embodiments, the FSM tool is rotating at not greater than 450 RPM. In some embodiments, the FSM tool is rotating at not greater than 400 RPM. In some embodiments, the FSM tool is rotating at not greater than 350 RPM. In some embodiments, the FSM tool is rotating at not greater than 300 RPM. In some embodiments, the FSM tool is rotating at not greater than 250 RPM. In some embodiments, the FSM tool is rotating at not greater than 200 RPM. In some embodiments, the FSM tool is rotating at not greater than 150 RPM. In some embodiments, the FSM tool is rotating at not greater than 100 RPM. In some embodiments, the FSM tool is rotating at not greater than 50 RPM.

[00068] In some embodiments, the FSM tool is rotating between 50 revolutions per minute (RPM) to 750 RPM. In some embodiments, the FSM tool is rotating between 100 RPM to 750 RPM. In some embodiments, the FSM tool is rotating between 150 RPM to 750 RPM. In some embodiments, the FSM tool is rotating between 200 RPM to 750 RPM. In some embodiments, the FSM tool is rotating between 250 RPM to 750 RPM. In some embodiments, the FSM tool is rotating between 300 RPM to 750 RPM. In some embodiments, the FSM tool is rotating between 350 RPM to 750 RPM. In some embodiments, the FSM tool is rotating between 400 RPM to 750 RPM. In some embodiments, the FSM tool is rotating between 450 RPM to 750 RPM. In some embodiments, the FSM tool is rotating between 500 RPM to 750 RPM. In some embodiments, the FSM tool is rotating between 550 RPM to 750 RPM. In some embodiments, the FSM tool is rotating between 600 RPM to 750 RPM. In some embodiments, the FSM tool is rotating between 650 RPM to 750 RPM. In some embodiments, the FSM tool is rotating between 700 RPM to 750 RPM.

[00069] In some embodiments, the FSM tool is rotating between 150 RPM to 700 RPM. In some embodiments, the FSM tool is rotating between 150 RPM to 650 RPM. In some embodiments, the FSM tool is rotating between 150 RPM to 600 RPM. In some embodiments, the FSM tool is rotating between 150 RPM to 550 RPM. In some embodiments, the FSM tool is rotating between 150 RPM to 500 RPM. In some embodiments, the FSM tool is rotating between 150 RPM to 450 RPM. In some embodiments, the FSM tool is rotating between 150 RPM to 400 RPM. In some embodiments, the FSM tool is rotating between 150 RPM to 350 RPM. In some embodiments, the FSM tool is rotating between 150 RPM to 300 RPM. In some embodiments, the FSM tool is rotating between 150 RPM to 250 RPM. In some embodiments, the FSM tool is rotating between 150 RPM to 200 RPM.

[00070] In some embodiments, the FSM tool is moving (e.g. travel speed) at least at 1 inch per minute (IPM). In some embodiments, the FSM tool is moving at least at 10 IPM. In some embodiments, the FSM tool is moving at least at 20 IPM. In some embodiments, the FSM tool is moving at least at 30 IPM. In some embodiments, the FSM tool is moving at least at 40 IPM. In some embodiments, the FSM tool is moving at least at 50 IPM. In some embodiments, the FSM tool is moving at least at 60 IPM. In some embodiments, the FSM tool is moving at least at 70 IPM. In some embodiments, the FSM tool is moving at least at 80 IPM. In some embodiments, the FSM tool is moving at least at 90 IPM. In some embodiments, the FSM tool is moving at least at 100 IPM.

[00071] In some embodiments, the FSM tool is moving (e.g. travel speed) at not greater than 100 inches per minute (IPM). In some embodiments, the FSM tool is moving at not greater than 90 IPM. In some embodiments, the FSM tool is moving at not greater than 80 IPM. In some embodiments, the FSM tool is moving at not greater than 70 IPM. In some embodiments, the FSM tool is moving at not greater than 60 IPM. In some embodiments, the FSM tool is moving at not greater than 50 IPM. In some embodiments, the FSM tool is moving at not greater than 40 IPM. In some embodiments, the FSM tool is moving at not greater than 30 IPM. In some embodiments, the FSM tool is moving at not greater than 20 IPM. In some embodiments, the FSM tool is moving at not greater than 10 IPM. In some embodiments, the FSM tool is moving at not greater than 1 IPM.

[00072] In some embodiments, the FSM tool is moving (e.g. travel speed) at 1 inch per minute (IPM) to 100 IPM. In some embodiments, the FSM tool is moving at 10 IPM to 100 IPM. In some embodiments, the FSM tool is moving at 20 IPM to 100 IPM. In some embodiments, the FSM tool is moving at 30 IPM to 100 IPM. In some embodiments, the FSM tool is moving at 40 IPM to 100 IPM. In some embodiments, the FSM tool is moving at 50 IPM to 100 IPM. In some embodiments, the FSM tool is moving at 60 IPM to 100 IPM. In some embodiments, the FSM tool is moving at 70 IPM to 100 IPM. In some embodiments, the FSM tool is moving at 80 IPM to 100 IPM. In some embodiments, the FSM tool is moving at 90 IPM to 100 IPM. [00073] In some embodiments, the FSM tool is moving at 1 IPM to 90 IPM. In some embodiments, the FSM tool is moving at 1 IPM to 80 IPM. In some embodiments, the FSM tool is moving at 1 IPM to 70 IPM. In some embodiments, the FSM tool is moving at 1 IPM to 60 IPM. In some embodiments, the FSM tool is moving at 1 IPM to 50 IPM. In some embodiments, the FSM tool is moving at 1 IPM to 40 IPM. In some embodiments, the FSM tool is moving at 1 IPM to 30 IPM. In some embodiments, the FSM tool is moving at 1 IPM to 20 IPM. In some embodiments, the FSM tool is moving at 1 IPM to 10 IPM.

[00074] In some embodiments, the average z force (e.g. the force exerted on the surface of the part by the FSM) is at least 1,000 lbs. In some embodiments, the average z force is at least 2,000 lbs. In some embodiments, the average z force is at least 3,000 lbs. In some embodiments, the average z force is at least 4,000 lbs. In some embodiments, the average z force is at least 5,000 lbs. In some embodiments, the average z force is at least 6,000 lbs. In some embodiments, the average z force is at least 7,000 lbs. In some embodiments, the average z force is at least 8,000 lbs. In some embodiments, the average z force is at least 9,000 lbs. In some embodiments, the average z force is at least 10,000 lbs. In some embodiments, the average z force is at least 11,000 lbs. In some embodiments, the average z force is at least 12,000 lbs. In some embodiments, the average z force is at least 13,000 lbs. In some embodiments, the average z force is at least 14,000 lbs. In some embodiments, the average z force is at least 15,000 lbs.

[00075] In some embodiments, the average z force is not greater than 15,000 lbs. In some embodiments, the average z force is not greater than 13,000 lbs. In some embodiments, the average z force is not greater than 11,000 lbs. In some embodiments, the average z force is not greater than 9,000 lbs. In some embodiments, the average z force is not greater than 7,000 lbs. In some embodiments, the average z force is not greater than 5,000 lbs. In some embodiments, the average z force is not greater than 3,000 lbs. In some embodiments, the average z force is not greater than 1,000 lbs.

[00076] In some embodiments, the average z force (e.g. the force exerted on the surface of the part by the FSM) is 1,000 lbs. to 15,000 lbs. In some embodiments, the average z force is 3,000 lbs. to 15,000 lbs. In some embodiments, the average z force is 5,000 lbs. to 15,000 lbs. In some embodiments, the average z force is 7,000 lbs. to 15,000 lbs. In some embodiments, the average z force is 9,000 lbs. to 15,000 lbs. In some embodiments, the average z force is 11,000 lbs. to 15,000 lbs. In some embodiments, the average z force is 13,000 lbs. to 15,000 lbs.

[00077] In some embodiments, the average z force is 1,000 lbs. to 13,000 lbs. In some embodiments, the average z force is 1,000 lbs. to 11,000 lbs. In some embodiments, the average z force is 1,000 lbs. to 9,000 lbs. In some embodiments, the average z force is 1,000 lbs. to 7,000 lbs. In some embodiments, the average z force is 1,000 lbs. to 5,000 lbs. In some embodiments, the average z force is 1,000 lbs. to 3,000 lbs.

[00078] In some embodiments, the FSM tool is configured with a straight, polygonal pin. In some embodiments, the FSM tool is configured with a threaded, polygonal pin. In some embodiments, the FSM tool is configured with a tapered, polygonal pin. In some embodiments, the FSM tool is configured with a straight, cylindrical pin (e.g. Figure 3a). In some embodiments, the FSM tool is configured with a threaded, cylindrical pin (e.g. Figure 3b). In some embodiments, the FSM tool is configured with a tapered, cylindrical pin (e.g. Figure 3c). In some embodiments, the FSM tool is configured with a straight, square pin (e.g. Figure 3d). In some embodiments, the FSM tool is configured with a threaded, square pin. In some embodiments, the FSM tool is configured with a tapered, square pin. In some embodiments, the FSM tool is configured with a straight, triangular pin (e.g. Figure 3e). In some embodiments, the FSM tool is configured with a threaded, triangular pin. In some embodiments, the FSM tool is configured with a tapered, triangular pin. In some embodiments, the FSM tool is configured with a tool head with a larger shoulder, such that the corresponding high z force and tool rotation are configured to mechanically work as the deposit layer solidifies, without disturbing the microstructure throughout the thickness of the AM build.

[00079] Figure 6A depicts a schematic embodiment of a cut-away side view of the columnar structure 600 of a directed energy deposition additive manufacturing process (e.g. depositing one to several AM build layers), which without being bound by any particular mechanism or theory, is believed to be a characteristic representation of a directed energy deposition (DED) AM build.

[00080] Figure 6B depicts a schematic embodiment of a cut-away side view of an AM build or AM part after the FSM tool passes over the AM build or part. In some embodiments, the FSM tool passes over one layer of the AM build. In some embodiments, the FSM tool makes one pass over one layer of the AM build. In some embodiments, the FSM tool makes multiple pass over one layer of the AM build. In some embodiments, the FSM tool passes over multiple layers of the AM build. In some embodiments, the FSM tool makes one pass over multiple layers of the AM build. In some embodiments, the FSM tool makes multiple pass over multiple layers of the AM build. In some embodiments, the corresponding microstructure of the AM build or AM part has transformed from a columnar structure 600 to an equiaxed structure 602, in accordance with the present disclosure.

[00081] As depicted in Figure 6C, a schematic embodiment of a cut-away side view of an AM build or AM part is shown, where the AM build process deposited another one to several AM layers (e.g. having a columnar structure 600) on top of the AM build having the FSM modified microstructure (e.g. equiaxed structure 602), in accordance with the present disclosure. [00082] As depicted in Figures 6 A - 6C, multiple AM passes followed by one or more FSM passes can be utilized to create an AM build or part having a wholly modified microstructure or a composite microstructure (e.g. a partially columnar structure and partially equiaxed structure in accordance with the present disclosure.

[00083] As shown in Figure 7, the AM build or AM part is configured with a portion having a wholly equiaxed structure 600 (from FSM tool processing), and two sections (e.g. regions in the cross-sectional part thickness across the AM build or AM part) that are columnar (as built via directed energy deposition additive manufacturing) interspaced at the upper, lower and middle regions with equiaxed structure portions 602, in accordance with the instant disclosure.

[00084] As shown in Figure 8, the AM build or AM part is configured with alternating regions of different microstructures, including an equiaxed structure 602 zone or layers interspaced in alternating configuration with a columnar (as built) structure 600 zone or layer, in accordance with the present disclosure. Thus, as shown in the schematic of Figure 8, the microstructure is configured in discrete layers of (from bottom to top) equiaxed structure, columnar structure, equiaxed structure, columnar structure, equiaxed structure, columnar structure, equiaxed structure, followed by columnar structure on the upper most region.

[00085] As shown in Figure 9, the AM build or AM part is configured with alternating layers of (1) equiaxed structure 600, (2) columnar structure 602, and (3) layers of composite structures 902, having regions of both columnar structures and equiaxed structures, in accordance with the present disclosure.

[00086] As shown in Figure 10, the AM build or AM part is configured with alternating regions of equiaxed structure 602 and columnar structure 600 in adjacent build layers, such that the AM part or AM build is configured with a composite, discontinuous microstructure, in accordance with the present disclosure.

[00087] As shown in Figure 11, the AM build or AM part is configured with predominantly equiaxed structure 602, with discrete portions within each (or certain) AM build layers having columnar structures 600, in accordance with the present disclosure.

[00088] In some embodiments, the FSM tool is configured to follow the AM deposition, such that the FSM grain modification is configured as an in-situ process.

[00089] In some embodiments, the FSM tool is configured to follow the AM deposition but is iteratively contacted with the AM build region (once the melt pool is solidified), such that the FSM grain modification is configured as an in-situ process to provide modified grain structures in regions of an AM part build, through various layers or portions that may overlap, partially overlap, intersect, or be specifically patterned in the AM build to provide an AM part having a tailored grain structure.

[00090] In some embodiments, the AM part is configured with an equiaxed portion and a columnar portion. In some embodiments, the AM part is configured with a predominantly columnar structure, which is interspaced with equiaxed regions (e.g. iteratively along different layer(s) or different portions of the AM part (e.g. through the build thickness).

[00091] As shown in Figure 2, the tooling is configured to impart a sufficient downward force (in the z direction) to maintain contact and transform (e.g. modify and/or break up) grain structures in the surface of the AM build. In some embodiments, the FSM tooling transforms the grain structure without creating a melt pool. Moreover, the FSM tooling is configured with a shoulder portion and a pin (e.g. probe portion) In some embodiments, the pin extends from the shoulder portion and interacts with the AM build, without being consumed by the FSM processing. While contacting the surface of the AM build (e.g. with continuous and/or varying amounts of downward force), the tool is configured to rotate (spin) while moving/traversing across the AM build in the x-y direction.

[00092] As depicted in Figure 2, the FSM tool during operation is configured with a leading edge of the rotating tool, a trailing edge of the rotating tool, an advancing side of the FSM region (e.g. a side having a modified microstructure as compared to the as-deposited microstructure) and a retreating side of the FSM region (e.g. a side having a modified microstructure as compared to the as-deposited microstructure).

[00093] In some embodiments, the FSM tool is attached to the AM machine. In some embodiments, the AM machine includes the energy source and feedstock distribution system. In some embodiments, the FSM tool is configured a fixed distance from the energy source and feedstock distribution system such that the distance from the AM deposition to the FSM tool processing is constant.

[00094] In some embodiments, the FSM tool is separate from the energy source and feedstock distribution system, but is configured to follow the AM deposition at a corresponding fixed distance such that the distance from the AM deposition to the FSM tool processing is constant. In some embodiments, the FSM tool is separate from the energy source and feedstock distribution system, such that the FSM distance to the AM deposition is variable.

[00095] In some embodiments, the FSM tool is separate from the energy source and feedstock distribution system, but is configured to intersect the AM deposition at a set region (e.g. via a set rastering pattern) and/or at corresponding transecting angles (e.g. such that the AM deposition is orthogonal or arcuate to the FSM tool pass). [00096] In some embodiments, the FSM tool is configured with a pin and shoulder, where the pin is configured to extend into the surface of the AM part. In one embodiment, the pin is configured to extend into the AM part, at least partially into a single AM build layer/deposition layer. In one embodiment, the pin is configured to extend into the AM part, across a single AM build layer/deposition layer. In one embodiment, the pin is configured to extend into the AM part, across a plurality of AM build layers/deposition beads (i.e. 2 or more layers).

[00097] In some embodiments, the FSM tool is configured with a flat lower portion (no pin), where the lower portion is configured to contact but not extend into the surface of the AM part such that frictional and/or mechanical force operate relative to the build surface. In some embodiments, during the friction stir modification process, tooling parameters are varied such that the pin intersects the surface of the AM part at different thicknesses, different speeds, and different average z forces.

[00098] As used herein, "AM feedstock" means: the one or more material(s) that are directed into an AM machine and deposited via an energy source into an AM build (e.g. build layer) during additive manufacturing, via the energy source. The AM feedstock may be any of the "feedstocks" described below.

[00099] For example, when a powder is utilized as an AM Feedstock (AM feed material), the AM process and related machine (e.g. as depicted in Figure 4) are a directed energy powder deposition (e.g. Optomec machine). Figure 4 depicts an embodiment of a directed energy deposition (powder-fed process) additive manufacturing machine. A "powder-fed process" is a type of directed energy deposition-based process in which metal-based powder is conveyed through a nozzle or other appropriate apparatus onto the build surface. The focused thermal energy is used to melt a layer or more of the powder into the shaped desired. This process may be repeated to create a solid three-dimensional component. The two dominant types of powder- fed processes are (e.g. non-limiting examples): 1) the work piece remains stationary, and the nozzle of a deposition head moves, and 2) the deposition head remains stationary, and the work piece is moved

[OOOlOOJAs another example, when a wire is utilized as an AM Feedstock (AM feed material), the AM process and related machine (e.g. as depicted in Figure 5) are a directed energy wire deposition (e.g. EB gun, Sciaky machine). Figure 5 depicts an embodiment of a directed energy deposition (wire-fed process) additive manufacturing machine. A "wire-fed process" is a type of directed energy deposition-based process in which metal-based wire feedstock is heated via focused thermal energy thereby creating a molten pool, followed by cooling the molten pool to a temperature below its solidus. Once the molten pool has cooled (e.g., to a temperature below its solidus), this process may be repeated until a portion of the additively manufactured product is produced.

[OOOlOlJAs used herein, "AM part" means: the part made via additive manufacturing. In some embodiments, the AM part is considered an AM preform, and undergoes further post-AM forming processing steps (e.g. heat treatments, working, machining, forging, milling, coating, surface treatments, and/or the like) before being utilized in an end-use application. In some embodiments, the AM part is configured for direct use in end-use applications (e.g. with no further post processing steps).

[000102]As used herein, "AM build" means: the AM part and/or optional build substrate, which is partially formed (e.g. in the process of being additively manufactured).

[000103]As used herein, "AM build layer" means: a discrete portion of an AM part build, which can be composed of a series of AM deposition paths (e.g. AM beads). [000104]As used herein "AM deposition path" means: the unit of AM build in a directed energy deposition AM process, as the AM material is deposited in a bead or path along an additive build and/or substrate.

[000105]In some embodiments, the AM melt pool size is configured with a corresponding size and depth such that the first layer after FSM pass does not penetrate more than 50% of the modified equiaxed structure of a previous layer. In some embodiments, the AM melt pool size is configured with a corresponding size and depth such that the first layer after FSM pass is configured to reform the directional cast structure microstructure (e.g. and not penetrate into previous FSM microstructure modified layers or portions).

[000106]In some embodiments, the FSM operating parameters (e.g. speed, tooling rotation, and downward force) are monitored and/or adjusted such that the FSM DED build process is configured in-situ, with a feedback loop and/or control system, which includes data on melt pool size, locations, energy beam information (e.g. z height), and or other build information to adjust the FSM operating parameters as needed to adjust the microstructure in the AM build and corresponding AM part.

[000107]As used herein, "feedstock" means the material that is fed into the additive system that is utilized by the additive system to build an AM part. Some non-limiting examples of feedstocks for use as an AM feedstock include aluminum, aluminum alloys, titanium, titanium alloys, steel, steel alloys, nickel, nickel alloys, and combinations thereof.

[000108]For example, the feedstock may include metals or alloys of titanium, aluminum, nickel (e.g., INCO EL), steel, and stainless steel, and titanium aluminide, among others. An alloy of titanium is an alloy having titanium as the predominant alloying element. An alloy of aluminum is an alloy having aluminum as the predominant alloying element. An alloy of nickel is an alloy having nickel as the predominant alloying element. An alloy of steel is an alloy having iron as the predominant alloying element, and at least some carbon. An alloy of stainless steel is an alloy having iron as the predominant alloying element, at least some carbon, and at least some chromium.

[000109] In one embodiment, the feedstock may be a titanium alloy. For example, the feedstock may comprise a Ti-6A1-4V alloy.

[000110]In another embodiment, the feedstock may be an aluminum alloy. As used herein, the phrase "the aluminum alloy" means an aluminum alloy selected from the group consisting of lxxx, 2xxx, 3xxx, 4xxx, 5xxx, 6xxx, 7xxx, and 8xxx series aluminum alloys registered with the Aluminum Association and unregistered variants of the same, as defined by the Aluminum Association document "International Alloy Designations and Chemical Composition Limits for Wrought Aluminum and Wrought Aluminum Alloys" (2009).

[000111]In some embodiments, the aluminum alloy is a lxxx series aluminum alloy. In some embodiments, the aluminum alloy is a 2xxx series aluminum alloy. In some embodiments, the aluminum alloy is a 3xxx series aluminum alloy. In some embodiments, the aluminum alloy is a 4xxx series aluminum alloy. In some embodiments, the aluminum alloy is a 5xxx series aluminum alloy. In some embodiments, the aluminum alloy is 6xxx series aluminum alloy. In some embodiments, the aluminum alloy is a 7xxx series aluminum alloy. In some embodiments, the aluminum alloy is an 8xxx series aluminum alloy.

[000112]In yet another embodiment, the feedstock may be a nickel alloy.

[000113]In yet another embodiment, the feedstock may be one of a steel and a stainless steel. [000114]In another embodiment, feedstock may be a metal matrix composite (e.g. ceramic or entrained particulate within one or more of the aforementioned feedstock metal or metal alloy materials).

[000115]In yet another embodiment, the feedstock may comprise a titanium aluminide alloy.

[000116]In one embodiment, a titanium alloy is a titanium aluminide alloy. For example, in one embodiment, the titanium aluminide alloy may include at least 48 wt. % Ti and at least one titanium aluminide phase, wherein the at least one titanium aluminide phase is selected from the group consisting of Ti₃Al, TiAl and combinations thereof. In another embodiment, the titanium aluminide alloy includes at least 49 wt. % Ti. In yet another embodiment, the titanium aluminide alloy includes at least 50 wt. % Ti. In another embodiment, the titanium aluminide alloy includes 5-49 wt. % aluminum. In yet another embodiment, the titanium aluminide alloy includes 30-49 wt. % aluminum, and the titanium alloy comprises at least some TiAl. In yet another embodiment, the titanium aluminide alloy includes 5-30 wt. % aluminum, and the titanium alloy comprises at least some Ti₃Al.

[000117] As used herein, "sequential" means: following in order (e.g. ascending order of AM deposition paths or layers)(e.g. first deposition path or layer, second deposition path or layer, third deposition path or layer, etc.). In some embodiments, the FSM tool is directed over at least a portion of each sequential AM build layer. In some embodiments, the first deposition path or layer is the first deposition path or layer formed by the AM process. In some embodiments, the first deposition path or layer is the first deposition path or layer that the FSM tool is directed over.

[000118] As used herein, "periodic" means: appearing or occurring at intervals (e.g. recurring frequencies). In some embodiments, the FSM tool is directed over at least a portion of periodic AM build layers. In some non-limiting examples, the FSM tool can be directed over every 3^r layer, or every 5^th layer or every 10^th layer.

[000119]In some embodiments, the FSM tool is directed over at least a portion of AM build layers at irregular intervals (e.g. no repetitive pattern). As a non-limiting example, the FSM tool can be directed over the 3^rd, 8^th, 23^rd, and 57^th layers.

[000120]In some embodiments, the FSM is utilized in-situ with the additive manufacturing depositions, to break up the cast microstructure (e.g. columnar structure) of the AM deposition/bead path and/or create a more equiaxed and wrought-like microstructure with additively manufactured materials.

[000121]In some embodiments, the FSM is utilized in-situ with the additive manufacturing depositions, to improve properties through microstructure refinement in as-deposited or post deposition part heat treatments.

[000122]In some embodiments, the FSM is utilized in-situ with the additive manufacturing depositions, to decrease anisotropic properties between growth direction (Z) and XY directions.

[000123]In some embodiments, the FSM is utilized in-situ with the additive manufacturing depositions, to increase the dynamic properties (e.g. fatigue, fatigue crack growth) of the AM build and corresponding AM part.

[000124] In some embodiments, the FSM is utilized in-situ with the additive manufacturing depositions, to improve the response to non-destructive part evaluation (CT and UT) through minimization of layers and interfaces in the grain boundaries and microstructure.

[000125]In some embodiments, the FSM is utilized in-situ with the additive manufacturing depositions, to enable qualification of additively manufactured parts through microstructure similarity to wrought structure parts. [000126]In some embodiments, the FSM is utilized in-situ with the additive manufacturing depositions, to enable qualification of direct energy deposition additively manufactured parts through microstructure similarity to wrought structure parts.

[000127]In some embodiments, the FSM is utilized in-situ with the additive manufacturing depositions, to enable scale-up direct energy deposition LENS additively manufactured parts to large parts.

[000128]In some embodiments, the FSM is utilized in-situ or iteratively with the additive manufacturing depositions, to enable scale-up direct energy deposition EBAM additively manufactured parts.

[000129]As used herein, the "grain size" is calculated by the following equation:

[000130]v/ = square root (— )

[000131] wherein Ai is the area of the individual grain as measured using commercial software Edax OIM version 8.0 or equivalent; and wherein vi is the calculated individual grain size assuming the grain is a circle. Grain size is determined based on a two-dimensional plane that includes the build direction of the additively manufactured product.

[000132] As used herein, the "area weighted average grain size" is calculated by the following equation:

[000134] wherein Ai is the area of each individual grain as measured using commercial software Edax OIM version 8.0 or equivalent; wherein vi is the calculated individual grain size assuming the grain is a circle; and wherein v-bar is the area weighted average grain size.

[000135]In one aspect, the methods of the present invention may decrease the grain size realized by the additive manufacturing build. For instance, in one embodiment an AM build layer realizes a first grain microstructure, wherein the first grain microstructure has a first average grain size. After the directing of a friction stir modification tool over at least a portion of a surface of the AM build layer, a second grain microstructure may be realized where the second grain microstructure has a second average grain size. In one embodiment, the second average grain size is less than the first average grain size. In one embodiment, the second average grain size is not greater than 95% of the first average grain size. In another embodiment, the second average grain size is not greater than 90% of the first average grain size. In yet another embodiment, the second average grain size is not greater than 80% of the first average grain size. In another embodiment, the second average grain size is not greater than 70% of the first average grain size. In yet another embodiment, the second average grain size is not greater than 60% of the first average grain size. In another embodiment, the second average grain size is not greater than 50% of the first average grain size. In yet another embodiment, the second average grain size is not greater than 40% of the first average grain size.

00136]In one embodiment, the first average grain size is at least 25 mm. In another embodiment, the first average grain size is at least 30 mm. In yet another embodiment, the first average grain size is at least 40 mm. In another embodiment, the first average grain size is at least 50 mm. In yet another embodiment, the first average grain size is at least 60 mm. In another embodiment, the first average grain size is at least 70 mm. In yet another embodiment, the first average grain size is at least 80 mm. In another embodiment, the first average grain size is at least 90 mm. In yet another embodiment, the first average grain size is at least 100 mm, or higher. In one or more of these embodiments, the grain size may be realized by a wire-fed additive manufacturing process (e.g., with a titanium alloy, a titanium aluminide, an aluminum alloy, or nickel alloy). [000137] In another aspect of the present invention, directing a friction stir modification (FSM) tool over at least a portion of a surface of the AM build layer may alter the orientation of the grains. For instance, an AM build layer may realize a first grain microstructure comprising a plurality of first grains, where the plurality of first grains are columnar grains, and where the plurality of first grains realize a grain orientation generally in the build direction (i.e., Z direction). Directing a friction stir modification tool over at least a portion of a surface may alter the grain orientation of the grains in the build direction. For instance, a second grain microstructure produced by a directing step may realize a spiral or helical shape, where the grain orientation changes with respect to the build direction (i.e., the Z direction).

[000138] The methods described herein may be suitable for producing products for use in a variety of industries. For instance, the additively manufactured products formed in accordance with the methods described herein may be in the form of aerospace components such as heat exchanger components and turbine components. In one embodiment, an additively manufactured product formed in accordance with the methods described herein is in the form of a compressor component (e.g., a turbocharger impeller wheel). Non-limiting examples of automotive applications may include interior or exterior trim/appliques, pistons, valves, and/or turbochargers. Other examples of automotive applications may include engine components and/or exhaust components, such as the manifold.

[000139] Aside from the applications described above, the additively manufactured products formed in accordance with the methods of the present disclosure may also be utilized in a variety of consumer products, such as any consumer electronic product, including laptops, cell phones, cameras, mobile music players, handheld devices, computers, televisions, microwave, cookware, washer/dryer, refrigerator, sporting goods, or any other consumer electronic product. In one embodiment, the visual appearance of the consumer electronic product meets consumer acceptance standards.

[000140] In another aspect, the additively manufactured products formed in accordance with the methods described herein are utilized in a structural application. In one embodiment, the additively manufactured products formed in accordance with the methods of the present disclosure are utilized in an aerospace structural application. For instance, the additively manufactured products formed in accordance with the methods of the present disclosure may be in the form of various aerospace structural components, including floor beams, seat rails, fuselage framing, bulkheads, spars, ribs, longerons, and brackets, among others. In another embodiment, the additively manufactured products formed in accordance with the methods of the present disclosure are utilized in an automotive structural application. For instance, the additively manufactured products formed in accordance with the methods of the present disclosure may be in the form of various automotive structural components including nodes of space frames, shock towers, and subframes, among others. In one embodiment, an additively manufactured product formed in accordance with the methods of the present disclosure is a body-in-white (BIW) automotive product.

[000141]In another aspect, the additively manufactured products formed in accordance with the methods of the present disclosure may be utilized in an industrial engineering application. For instance, the additively manufactured products formed in accordance with the methods described herein may be in the form of various industrial engineering products, such as tread-plate, tool boxes, bolting decks, bridge decks, and ramps, among others.

[000142] In some embodiments, the additively manufactured products formed in accordance with the methods of the present disclosure may be utilized in a variety of products including the likes of medical devices, transportation systems and security systems, to name a few. In other embodiments, the additively manufactured products formed in accordance with the methods of the present disclosure may be incorporated in goods including the likes of car panels, media players, bottles and cans, office supplies, packages and containers, among others.

r0001431Example: FSP Grain Structure Modification on AM (EBAM) Ti6A14V

[000144] In order to demonstrate that the microstructure cross sections on an AM build can be modified with post-build friction stir processing to break up columnar structure, a Titanium 6A1 4V, feed material was deposited via an EBAM AM machine onto a base metal (e.g. substrate or build plate) of Titanium 6A1 4V, 1" thick, to form an AM build having the following dimensions: 0.125" diameter 9 beads wide x 4 high.

[000145JA commercially available friction stir welding system and tooling was acquired, and modified to provide a friction stir processing tool (e.g. tool shortened and tool configured with a gas shroud). The gas shroud was configured to protect the FS processing tool and the titanium from undergoing a high temperature oxidation by feeding an argon purge to the area that the tooling was working. The shroud was configured with two gas ports: one configured to flood the FS tool with Argon and the other configured to flood the weld area with Argon, with an approximate argon flow rate to each area of 100 CFH.

[000146] The AM preform (AM build and plate) was fixed via clamps to hold the part flat and prevent moving laterally or moving along the FSM path while undergoing processing. Prior to FSM of the AM build, the surface was cleaned with an organic solvent and abrasive wipe to remove debris, if any, and prepare the surface for FSM. [000147]When applying friction stir modification processing to the AM build, the parameters for this experimental run were as follows: Spindle RPM - 224; Travel Speed - 4.5-4.9 IPM; Average Force Z (Forge) - 3547-3850 lbs.

[000148]The FSM processing provided a visually observable modification to the AM deposit. After seven total passes were completed along a portion of the AM build, the resulting FSM part was cross-sectioned for further analysis of the resulting microstructure. The metallographic cross-section confirmed the visual observation: the friction stir processing was successful in modifying the columnar structure of the AM build. More specifically, metallography in the cross-section confirmed that the Friction Stir Processing successfully broke up and refined the AM (EBAM) deposit grain size.

[000149]While a number of embodiments of the present invention have been described, it is understood that these embodiments are illustrative only, and not restrictive, and that many modifications may become apparent to those of ordinary skill in the art. However, it is to be expressly understood that such modifications and adaptations are within the spirit and scope of the present disclosure. Further still, the various steps may be carried out in any desired order (and any desired steps may be added and/or any desired steps may be eliminated).

Claims

CLAIMS: We claim:

1. A method, comprising:

a. additively manufacturing at least one layer of an AM build,

i. wherein at least a portion of the AM build comprises a metallic AM

feedstock, and

ii. wherein the at least one AM build layer comprises a first grain

microstructure;

b. directing a friction stir modification (FSM) tool over at least a portion of a surface of the AM build layer to provide friction stir modification compressive stresses, mechanical stirring forces, or a combination thereof to the AM build layer in a region of the AM build;

c. wherein the friction stir modification tool is configured to transform the first grain microstructure into a second grain microstructure, wherein the first grain microstructure is a columnar structure and the second grain microstructure is an equiaxed structure.

2. The method of claim 1, wherein the FSM tool is directed over an entire surface of an AM bead deposition.

3. The method of claim 1, wherein the FSM tool is directed over at least a portion of an AM bead deposition.

The method of claim 1, wherein the FSM tool is directed iteratively over at least a portion of an AM bead deposition.

The method of claim 1, wherein the FSM tool is directed over a portion of the surface of the AM build.

The method of claim 1, wherein the FSM tool is directed over an entire surface of the AM build.

The method of claim 1, wherein the FSM tool is directed over at least a portion of each sequential AM build layer, such that the cross-sectional microstructure for a given region of the AM build layer varies from the columnar structure to the equiaxed structure.

The method of claim 1, wherein the FSM tool is directed over at least a portion of each sequential AM build layer, such that the cross-sectional microstructure for a given region of the AM build layer is the columnar structure and an adjacent cross-sectional microstructure is the equiaxed structure.

The method of claim 1, wherein the friction stir processing via the FSM tool is completed in-situ, during directed energy deposition additive manufacturing.

10. The method of claim 1, wherein the FSM tool is utilized on every AM bead in an AM build, such that the corresponding microstructure of each AM build layer is transformed from the columnar structure to the equiaxed structure.

11. The method of claim 1, wherein the FSM tool is utilized in regions of every AM bead in an AM build.

12. The method of claim 1, wherein the FSM tool is utilized in alternating layers of an AM build.

13. The method of claim 1, wherein the FSM tool is utilized in alternating AM bead

deposition in an AM build.

14. The method of claim 1, wherein the FSM tool is utilized in layers of an AM build at irregular intervals.

15. The method of claim 1, wherein the first grain microstructure realizes a first average grain size, and wherein the second grain microstructure realizes a second average grain size.

16. The method of claim 15, wherein the second average grain size is less than the first average grain size.

17. The method of claim 16, wherein the second average grain size is not greater than 95% of the first average grain size, or is not greater than 90% of the first average grain size, or is not greater than 80% of the first average grain size, or is not greater than 70% of the first average grain size, or is not greater than 60% of the first average grain size, or is not greater than 50% of the first average grain size, or is not greater than 40% of the first average grain size.

18. The method of claim 1, wherein the directing the friction stir modification (FSM) tool is a first directing step, and wherein the method comprises a second directing step; wherein the second directing step comprises transforming the second grain microstructure to a third grain microstructure.

19. The method of claim 18, wherein the third grain microstructure realizes a third average grain size, wherein the third average grain size is less than the second average grain size.

20. The method of claim 1, wherein the AM build is a titanium alloy.

21. The method of claim 1, wherein the AM build is a titanium aluminide alloy.

22. The method of claim 1, wherein the AM build is an aluminum alloy.

23. The method of claim 1, wherein the AM build is a steel alloy.

The method of claim 1, wherein the AM build is a nickel alloy.

The method of claim 1, wherein the AM build is an aerospace component.

The method of claim 1, wherein the AM build is an automotive component.

The method of claim 1, wherein the AM build is a turbine component.

The method of claim 1, wherein the AM build is a consumer product component.

29. The method of claim 1, wherein the FSM tool comprises one of: a straight, polygonal pin; a straight, cylindrical pin; a straight, square pin; or a straight, triangular pin.

The method of claim 1, wherein the FSM tool is configured with one of: a threaded, polygonal pin; a threaded, cylindrical pin; a threaded, square pin; or a threaded, triangular pin

31. The method of claim 1, wherein the FSM tool is configured with one of: a tapered,

polygonal pin; a tapered, cylindrical pin; a tapered, square pin; or a tapered, triangular pin.