Systems and methods for forming directional crystal microstructures

Abstract

A 3D printed metallic object having large scale cubic crystal structures is produced by controlling hatch distances and melt pool depth. Moving the melt pool in a first powder layer along a first layer scan pattern produces a first patterned layer. The scan pattern has parallel scan lines spaced by a hatch distance along a hatch direction perpendicular to the scan lines. As the melt pool cools, a dendrite grows in a dendrite growth direction. The hatch distance promotes a dendrite growth direction orthogonal to the scan lines and discourages a dendrite growth direction with a directional component opposite the hatch direction. Moving the melt pool in a powder layer on top the first patterned layer produces a second patterned layer. The melt pool's pool depth discourages dendrite growth directions in the first patterned layer from being less than 45 degrees relative to the melt pool's top surface.

Description

SYSTEMS AND METHODS FOR FORMING DIRECTIONAL CRYSTALMICROSTRUCTURESTECHNICAL FIELD

[0001] Embodiments are generally related to additive manufacturing, 3D printing, selective laser melting (SLM) printing of 3D objects, and 3D printing of cubic materials. The embodiments are also related to controlling melt pool shape and overlap to thereby form directional and single crystal microstructures in a 3D printed object.BACKGROUND

[0002] Objects can be printed by 3D printers using a variety of techniques such as stereolithography (SLA), selective laser melting (SLM), selective laser sintering (SLS), fused deposition modeling (FDM), direct metal printing (DMP), electron beam melting (EBM), directed energy deposition (DED), electron beam powder bed fusion (EBPF), and laser powder bed fusion (LPBF). The field is developing rapidly with new techniques being developed and known techniques being refined. Many of the techniques operate by forming a patterned layer of material onto a substrate and then forming additional layers over previously produced layers. Some techniques (e.g., DED, etc.) produce patterned layers by producing a melt pool and then adding material to the melt pool while moving the melt pool. Some techniques (e.g., SLM, EBPF, etc.) produce patterned layers by laying down a layer of powdered material and then producing the patterned layer of solid material by selectively melting the powdered material. The materials used for additive manufacturing are very often cubic materials. Cubic materials are materials that form cubic crystal structures having <100> orientations.

[0003] Additive manufacturing is a technology that is merely decades old whereas classical processes are thousands of years old. For example, the bronze age began approximately 5000 years ago and the iron age began 3000 years ago. The classical processes are highly refined because they have been studied and improved for millennia. Systems and methods are needed for producing additively manufactured objects that meet or exceed the materialproperties exhibited by objects produced using classical processes.BRIEF SUMMARY

[0004] The following summary is provided to facilitate an understanding of some of the innovative features unique to the embodiments disclosed and is not intended to be a full description. A full appreciation of the various aspects of the embodiments can be gained by taking the entire specification, claims, drawings, and abstract as a whole.

[0005] One aspect of the subject matter described in this disclosure can be implemented in a method. The method can include depositing a first powder layer, and producing a first patterned layer by moving a melt pool in the first powder layer along a first layer scan pattern that includes a plurality of scan lines, wherein the scan lines are parallel and spaced by a hatch distance along a hatch direction that is perpendicular to the scan lines, a dendrite grows in a dendrite growth direction where the melt pool cools, the first layer scan pattern promotes the dendrite growth direction being orthogonal to the scan lines, and the hatch distance discourages the dendrite growth direction that has a directional component that is opposite the hatch direction.

[0006] Another aspect of the subject matter described in this disclosure can be implemented by a system. The system can include a powder bed, a powder feeder configured to deposit a plurality of powder layers by depositing a powder on the powder bed, a beam source configured to produce a melt pool in a topmost powder layer, and a beam scanner configured to produce a plurality of patterned layers from the powder layers by moving the melt pool relative to the powder bed, wherein the powder layers include a first powder layer, a first one of the patterned layers is produced by moving the melt pool in the first powder layer along a first layer scan pattern that includes a plurality of scan lines, the scan lines are parallel and spaced by a hatch distance along a hatch direction that is perpendicular to the scan lines, a dendrite grows in a dendrite growth direction where the melt pool cools, the first layer scan pattern promotes the dendrite growth direction being orthogonal to the scan lines, and the hatch distance discourages the dendrite growth direction from having a directional component that is opposite the hatch direction.

[0007] Yet another aspect of the subject matter described in this disclosure can be implemented in a system. The system can include a plurality of patterned layers of a cubicmaterial, and a cubic crystal structure that extends from a first one of the patterned layers to a second one of the patterned layers, wherein each one of the patterned layers is formed by moving a melt pool in a scan pattern that includes a plurality of scan lines, and the cubic crystal structure includes a dendrite that has a long axis that is orthogonal to the scan lines.

[0008] In some implementations of the methods and systems, the hatch distance promotes the dendrite growth direction being at 45 degrees relative to a top surface of the melt pool. In some implementations of the methods and systems, the first powder layer includes a cubic material. In some implementations of the methods and systems, the first powder layer includes iron, nickel, or cobalt. In some implementations of the methods and systems, the first patterned layer overlays a previous patterned layer, a cubic crystal structure is in the first patterned layer and is in the previous patterned layer, and the cubic crystal structure includes the dendrite that has a growth direction that is in the dendrite growth direction. In some implementations of the methods and systems, the dendrite growth direction in the first patterned layer is the same as the dendrite growth direction in the second patterned layer. In some implementations of the methods and systems, the dendrite growth direction in the first patterned layer is perpendicular to the dendrite growth direction in the second patterned layer.

[0009] In some implementations of the methods and systems, the method further includes depositing a second powder layer on the first patterned layer, and producing a second patterned layer by moving the melt pool in the second powder layer along a second layer scan pattern that includes a plurality of second layer scan lines, wherein the melt pool in the second powder layer has a pool depth that discourages the dendrite growth direction in the first patterned layer from being less than 45 degrees relative to a top surface of the melt pool.

[0010] In some implementations of the methods and systems, the first one of the patterned layers overlays a previous patterned layer, a cubic crystal structure is in the first one of the patterned layers and is in the previous patterned layer, and the cubic crystal structure includes the dendrite. In some implementations of the methods and systems, the powder layers include a second powder layer on top of the first powder layer, and a second one of the patterned layers is produced by moving the melt pool in the second powder layer along a second layer scan pattern that includes a plurality of second layer scan lines, wherein themelt pool in the second powder layer has a pool depth that discourages the dendrite growth direction in the first one of the patterned layers from being less than 45 degrees relative to a top surface of the melt pool. In some implementations of the methods and systems, the dendrite growth direction in the first one of the patterned layers is the same as the dendrite growth direction in the second one of the patterned layers. In some implementations of the methods and systems, the dendrite growth direction in the first one of the patterned layers is perpendicular to the dendrite growth direction in the second one of the patterned layers.

[0011] In some implementations of the methods and systems, the system further includes the plurality of patterned layers, and a cubic crystal structure that extends from the first one of the patterned layers to a second one of the patterned layers, wherein the patterned layers, the cubic crystal structure, and the dendrite include a cubic material, and wherein the cubic crystal structure includes the dendrite.

[0012] In some implementations of the methods and systems, the system further includes at least one additional patterned layer is between the first one of the patterned layers and the second one of the patterned layers, and the first one of the patterned layers is at least 10 mm from the second one of the patterned layers.BRIEF DESCRIPTION OF THE DRAWINGS

[0013] The accompanying figures, in which like reference numerals refer to identical or functionally similar elements throughout the separate views and which are incorporated in and form a part of the specification, further illustrate the embodiments and, together with the detailed description, serve to explain the embodiments disclosed herein.

[0014] FIG. 1 is a high-level conceptual figure of a SLM style 3D printer, according to some aspects.

[0015] FIG. 2 is a high level conceptual diagram that illustrates a scan pattern with a melt pool and a hatch distance, according to some aspects.

[0016] FIG. 3A is a high level conceptual diagram that illustrates a dendrite that has grown through multiple patterned layers, according to some aspects.

[0017] FIG. 3B is a high level conceptual diagram that illustrates a cubic crystal structure that includes the dendrite illustrated in FIG. 3A, according to some aspects.

[0018] FIG. 4A is a high level conceptual diagram that illustrates dendrites growing in a melt pool, according to some aspects.

[0019] FIG. 4B is a high level conceptual diagram that illustrates dendrites growing in two adjacent scan lines, according to some aspects.

[0020] FIG. 5A is a diagram that illustrates dendrite growth directions in a melt pool, according to some aspects.

[0021] FIG. 5B is a diagram that illustrates a hatch distance that discourages dendrite growth directions that have a directional component that is opposite to the hatch direction, according to some aspects.

[0022] FIG. 50 is another diagram that illustrates a hatch distance that discouragesdendrite growth directions that have a directional component that is opposite to the hatch direction, according to some aspects.

[0023] FIG. 6A is a diagram that illustrates a pool depth that discourages dendrite growth directions from being less than 45 degrees relative to the top surface of the melt pool, according to some aspects.

[0024] FIG. 6B is another diagram that illustrates a pool depth that discourages dendrite growth directions from being less than 45 degrees relative to the top surface of the melt pool, according to some aspects.

[0025] FIG. 7A is a diagram that illustrates a dendrite having a first dendrite portion 702 that has a first dendrite growth direction 703 in a first patterned layer, according to some aspects.

[0026] FIG. 7B is a diagram that illustrates the dendrite illustrated in FIG. 7A having a second dendrite portion 706 having a second dendrite growth direction 705 that is perpendicular to the first dendrite growth direction 703, according to some aspects.

[0027] FIG. 8 is a high level flow diagram that illustrates a method for forming directional crystal microstructures, according to some aspects.DETAILED DESCRIPTION

[0028] The particular values and configurations discussed in the following non-limiting examples can be varied and are cited merely to illustrate one or more embodiments and are not intended to limit the scope thereof.

[0029] Example embodiments will now be described more fully hereinafter with reference to the accompanying drawings, in which illustrative embodiments are shown. The embodiments disclosed herein can be embodied in many different forms and should not be construed as limited to the embodiments set forth herein; rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the embodiments to those skilled in the art. Like numbers refer to like elements throughout.

[0030] The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting. 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 "comprise" 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, elements, components, and / or groups thereof.

[0031] Throughout the specification and claims, terms may have nuanced meanings suggested or implied in context beyond an explicitly stated meaning. Likewise, the phrase “in one embodiment” as used herein does not necessarily refer to the same embodiment and the phrase “in another embodiment” as used herein does not necessarily refer to a different embodiment. It is intended, for example, that claimed subject matter include combinations of example embodiments in whole or in part.

[0032] Unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art. It will be further understood that terms, such as those defined in commonly used dictionaries, should be interpreted as having a meaning that is consistent with their meaning in the contextof the relevant art and will not be interpreted in an idealized or overly formal sense unless expressly so defined herein.

[0033] It is contemplated that any embodiment discussed in this specification can be implemented with respect to any method, kit, reagent, or composition of the invention, and vice versa. Furthermore, compositions of the invention can be used to achieve methods of the invention.

[0034] It will be understood that particular embodiments described herein are shown by way of illustration and not as limitations of the invention. The principal features of this invention can be employed in various embodiments without departing from the scope of the invention. Those skilled in the art will recognize or be able to ascertain using no more than routine experimentation, numerous equivalents to the specific procedures described herein. Such equivalents are considered to be within the scope of this invention and are covered by the claims.

[0035] The use of the word “a” or “an” when used in conjunction with the term “comprising” in the claims and / or the specification may mean “one,” but it is also consistent with the meaning of “one or more,” “at least one,” and “one or more than one.” The use of the term “or” in the claims is used to mean “and / or” unless explicitly indicated to refer to alternatives only or the alternatives are mutually exclusive, although the disclosure supports a definition that refers to only alternatives and “and / or.” Throughout this application, the term “about” is used to indicate that a value includes the inherent variation of error for the device, the method being employed to determine the value, or the variation that exists among the study subjects.

[0036] As used in this specification and claim(s), the words “comprising” (and any form of comprising, such as “comprise” and “comprises”), “having” (and any form of having, such as “have” and “has”), “including” (and any form of including, such as “includes” and “include”) or “containing” (and any form of containing, such as “contains” and “contain”) are inclusive or open-ended and do not exclude additional, unrecited elements or method steps.

[0037] The term “or combinations thereof” as used herein refers to all permutations and combinations of the listed items preceding the term. For example, “A, B, C, or combinationsthereof” is intended to include at least one of: A, B, C, AB, AC, BC, or ABC, and if order is important in a particular context, also BA, CA, CB, CBA, BCA, ACB, BAC, or CAB. Continuing with this example, expressly included are combinations that contain repeats of one or more item or term, such as BB, AAA, AB, BBC, AAABCCCC, CBBAAA, CABABB, and so forth. The skilled artisan will understand that typically there is no limit on the number of items or terms in any combination, unless otherwise apparent from the context.

[0038] All of the compositions and / or methods disclosed and claimed herein can be made and executed without undue experimentation in light of the present disclosure. While the compositions and methods of this invention have been described in terms of preferred embodiments, it will be apparent to those of skill in the art that variations may be applied to the compositions and / or methods and in the steps or in the sequence of steps of the method described herein without departing from the concept, spirit, and scope of the invention. All such similar substitutes and modifications apparent to those skilled in the art are deemed to be within the spirit, scope and concept of the invention as defined by the appended claims.

[0039] FIG. 1 is a high-level conceptual figure of a SLM style 3D printer 100, according to some aspects. A powder feeder 110 deposits powder 1 12 to produce a powder layer 105 in a powder bed 108. The powder layer that is deposited first can lie directly on the powder bed or on a substrate that may be placed in the powder bed before the powder layers are deposited. A beam scanner 101 can move a beam source 102 or steer an energy beam 1 11 that is produced by the beam source. The energy beam may be a laser beam, an electron beam, etc. The energy beam 111 produces a melt pool 104 where the energy beam 1 1 1 melts some of the powder in the powder bed 108. The melt pool 104 has a melt pool depth 103. The melt pool depth 103 is illustrated as being large enough to also melt some of the patterned layer 106 directly underneath the powder layer 105. The beam scanner moves the melt pool 104 in a path through the topmost powder layer to selectively melt some of the powder and thereby produce a patterned layer. The powder layer that is deposited first becomes the bottom patterned layer 107. A 3D object is printed by iteratively depositing a powder layer and using the energy beam to melt a pattern into that powder layer, thereby producing a patterned layer. The powder can be a cubic material. Cubic materials are materials that form cubic crystal structures having <100> orientations. Iron, nickel, and cobalt are examples of cubic materials. As such, the powder may be an iron powder, a nickelpowder, or a cobalt powder.

[0040] The example illustrated in FIG. 1 shows a bottom patterned layer 107 that overlays the powder bed 108. Each patterned layer overlays the powder bed and one or more previous layers. A topmost patterned layer may be produced by moving the melt pool through the powder layer 105. That topmost patterned layer will overlay the previous patterned layer shown as patterned layer 106 in the example illustrated in FIG. 1 .

[0041] FIG. 2 is a high level conceptual diagram that illustrates a scan pattern 200 with a melt pool 104 and a hatch distance 203, according to some aspects. The scan pattern 200 can include a large number of scan lines 201 that may be parallel to one another as shown in FIG. 2. The hatch distance 203 is the distance between the scan lines 201. The hatch direction is the direction from a previous scan line to a subsequent scan line in the scan pattern. The hatch direction 204 can be perpendicular to the scan lines 201. The beam scanner moves the melt pool 104 along the scan pattern. For simplicity, the melt pool is shown as a circle where the energy beam 11 1 meets the powder layer and melts the powder at that location. In practice, the melt pool is much longer because the energy beam melts material in a pattern and melted material remains melted for a short period of time.

[0042] FIG. 3A is a high level conceptual diagram that illustrates a dendrite that has grown through multiple patterned layers, according to some aspects. Crystalline materials form crystals as they solidify from a liquid state (as in the melt pool) to a solid state. As the crystals grow, they can form dendrites such as dendrite 301 . A region of a crystal having the same crystal orientation is called a dendrite. A dendrite can have a long axis 306 in a preferred growth direction. Those practiced in the art understand that crystals growing within a melt have preferred growth directions that are governed by temperature gradients within the melt and by the orientation of crystals that have already formed in or adjacent to the melt. The crystals growing in a preferred growth direction form dendrites. The dendrite 301 illustrated in FIG. 3A extends from a first patterned layer 305, and extends through a second patterned layer 304, a third patterned layer 303 and a fourth patterned layer 302. The dendrite is shown extending to the top of the fourth patterned layer 302 and may extend further through at least one additional patterned layer above the fourth patterned layer. The dendrite has grown through multiple patterned layers because a dendrite in a patterned layer can act as a seed crystal for growing the dendrite into the next layer.

[0043] FIG. 3B is a high level conceptual diagram that illustrates a cubic crystal structure 310 that includes the dendrite illustrated in FIG. 3A, according to some aspects. The temperature gradients in a melt pool tend to be perpendicular to the sidewall of the melt pool. As such, changes in the directions of the scan lines from layer to layer can change the preferred direction in which crystals grow within the layers. When the material being printed is a cubic crystalline material, a ninety degree change in the hatch direction from one layer to the next can result in a ninety degree change in the preferred crystal growth direction, thereby producing a cubic crystal structure having dendrites with ninety degree corners.

[0044] FIG. 4A is a high level conceptual diagram that illustrates dendrites 301 growing in a melt pool 104, according to some aspects. The energy beam 111 melts the powder in the powder bed. The beam scanner 101 moves the energy beam 111 to thereby move the melt pool 104 in the scan direction 401 . The melt pool is illustrated as a portion of the first scan line 403 that has a fully melted section to the right and a section to the left that has cooled enough for dendrites 301 to grow. The dendrites 301 are growing in dendrite growth directions 402, 406 that are perpendicular to the scan direction because the temperature gradient is perpendicular to the scan direction and because material that is not melted at the side of the melt pool may act as a seed layer from which the dendrites can grow. In FIG. 4A, the dendrites 301 are shown growing from both sides of the first scan line 403. Some of the dendrites have a dendrite growth direction 402 that have a directional component in the hatch direction 204. Some of the dendrites have a dendrite growth direction 406 that have a directional component that is opposite the hatch direction 204.

[0045] FIG. 4B is a high level conceptual diagram that illustrates dendrites growing in two adjacent scan lines, according to some aspects. The melt pool has melted material along a second scan line 405 that is parallel to the first scan line 403. The distance between the first scan line 403 and the second scan line 405 is the hatch distance 203. The energy beam has melted the dendrites that have a dendrite growth direction 406 with a directional component that is opposite the hatch direction 204. The dendrites that have a dendrite growth direction 402 with a directional component in the hatch direction 204 have grown larger. As such, the hatch distance has discouraged dendrite growth directions that have a directional component that is opposite to the hatch direction.

[0046] FIG. 5A, FIG. 5B and FIG. 5C illustrate dendrite growth directions 402 in a melt pool being produced by an energy beam moving in a scan pattern. The directions of the scan lines are normal to the illustration and are therefore not shown.

[0047] FIG. 5A is a diagram that illustrates dendrite growth directions in a melt pool, according to some aspects. The dendrite growth directions 402 are normal to the side 502 of the melt pool. The top 503 of the melt pool is the upper surface of the melted material. An angle 501 relative to the top of the melt is shown. The specific angle illustrated in FIG. 5A is 45 degrees relative to the top of the melt pool. In FIG. 5A the energy beam has been scanned along a first scan line of a scan pattern that has a hatch direction 204 as shown in FIG. 5A. The dendrite growth directions on the left side of the melt pool have a direction component that is in the hatch direction 204. The dendrite growth directions on the right side of the melt pool have a direction component that is opposite the hatch direction 204.

[0048] FIG. 5B is a diagram that illustrates a hatch distance 203 that discourages dendrite growth directions that have a directional component that is opposite to the hatch direction 204, according to some aspects. The energy beam has been scanned along a second scan line that is one hatch distance 203 to the right of that first scan line. Scanning the beam along the second scan line melts dendrites that have a dendrite growth direction 406 with a directional component that is opposite the hatch direction 204. As such, the hatch distance has discouraged dendrite growth directions that have a directional component that is opposite to the hatch direction.

[0049] FIG. 5C is another diagram that illustrates a hatch distance that discourages dendrite growth directions that have a directional component that is opposite to the hatch direction, according to some aspects. The energy beam has been scanned along a third scan line and a fourth scan line at a spacing equaling the hatch distance 203. Scanning the beam along the third and fourth scan lines melts dendrites that have a dendrite growth direction 406 with a directional component that is opposite the hatch direction 204. As such, the hatch distance has discouraged dendrite growth directions that have a directional component that is opposite to the hatch direction. Reducing the hatch distance further can discourage dendrite growth directions having directional components in the hatch direction. For example, a hatch distance can be selected that melts even more of the proceeding scan line to thereby also discouraging dendrite growth directions normal to the hatch direction or where thecosine between the hatch direction and the dendrite growth direction is less than a specific value.

[0050] FIG. 6A is a diagram that illustrates a pool depth that discourages dendrite growth directions from being less than 45 degrees relative to the top surface of the melt pool, according to some aspects. In FIG. 6A, the first layer has been patterned, a second powder layer has been deposited, and the energy beam has been scanned through the second powder layer. The second powder layer has a layer height 601 that is less than the pool depth 103. The pool overlap 602 is the extent to which the melt pool extends into the underlying layer. As can be seen, the dendrite growth directions become more parallel to the top of the melt pool the closer they are to the top of the melt pool. As such, melting the top portion of the underlying layer discourages dendrite growth directions that have an angle relative to the top of the melt pool that is smaller than a certain angle. For a cubic crystalline material, it is desirable to have dendrites grow at a 45 degree angle relative to the top of the melt pool because 90 degree rotations of the hatch direction from layer to layer can result in the dendrite growth directions changing by 90 degrees. As such, the same cubic crystal structure may grow from the bottom layer to the top layer.

[0051] FIG. 6B is another diagram that illustrates a pool depth that discourages dendrite growth directions from being less than 45 degrees relative to the top surface of the melt pool, according to some aspects. In FIG. 6B, the second layer has been patterned, a third powder layer has been deposited, and the energy beam has been scanned through the third powder layer. As in FIG. 6A, the third powder layer has a layer height 601 that is less than the pool depth 103. It can be seen that the 45 degree dendrites become predominant as more layers are patterned.

[0052] FIG. 7A is a diagram that illustrates a dendrite having a first dendrite portion 702 that has a first dendrite growth direction 703 in a first patterned layer, according to some aspects. The hatch direction of the scan pattern for the first patterned layer is the first hatch direction 701. The first dendrite growth direction 703 is in the first hatch direction 701 because, as discussed above, the temperature gradients in the scan pattern promote dendrite growth directions that are orthogonal to the scan lines. The scan lines are orthogonal to the hatch direction. The dendrite growth direction is not necessarily parallel to the hatch direction because the structure is three dimensional. For example, the dendrite portion 702may be growing out of the plane of the illustration at a 45 degree angle.

[0053] FIG. 7B is a diagram that illustrates the dendrite illustrated in FIG. 7A having a second dendrite portion 706 having a second dendrite growth direction 705 that is perpendicular to the first dendrite growth direction 703, according to some aspects. The second dendrite portion 706 is in a second patterned layer that overlays the first patterned layer. The hatch direction in the second patterned layer is the second hatch direction 704. Here, the second hatch direction 704 is rotated by 90 degrees relative to the first hatch direction 701 thereby rotating the preferred dendrite growth direction by 90 degrees. The preferred dendrite growth direction is not necessarily in the plane of the illustrations. As such, the second dendrite portion 706 is orthogonal to the first dendrite portion 702. In this nonlimiting example, a 90 degree rotation is shown. Those practiced in the art understand that there are other useful rotations such as 180 degrees or 0 degrees (no rotation) achievable with the materials under consideration.

[0054] FIG. 8 is a high level flow diagram that illustrates a method for forming directional crystal microstructures, according to some aspects. After the start, at block 801 the method can deposit a first powder layer. At block 802, the method can produce a first patterned layer by moving a melt pool in the first powder layer along a first layer scan pattern that includes a plurality of scan lines, wherein the scan lines are parallel and spaced by a hatch distance along a hatch direction that is perpendicular to the scan lines, a dendrite grows in a dendrite growth direction where the melt pool cools, the hatch distance promotes the dendrite growth direction being orthogonal to the scan lines, the hatch distance discourages the dendrite growth direction that has a directional component that is opposite the hatch direction. At block 803, the method can deposit a second powder layer on the first patterned layer. At block 804, the method can produce a second patterned layer by moving the melt pool in the second powder layer along a second layer scan pattern that includes a plurality of second layer scan lines, wherein the melt pool in the second powder layer has a pool depth that discourages the dendrite growth direction in the first patterned layer from being less than 45 degrees relative to the top surface of the melt pool.

Claims

CLAIMSWhat is claimed is:1 . A method comprising: depositing a first powder layer; and producing a first patterned layer by moving a melt pool in the first powder layer along a first layer scan pattern that includes a plurality of scan lines, wherein: the scan lines are parallel and spaced by a hatch distance along a hatch direction that is perpendicular to the scan lines; a dendrite grows in a dendrite growth direction where the melt pool cools; the first layer scan pattern promotes the dendrite growth direction being orthogonal to the scan lines; and the hatch distance discourages the dendrite growth direction that has a directional component that is opposite the hatch direction.

2. The method of claim 1 , wherein the hatch distance promotes the dendrite growth direction being at 45 degrees relative to a top surface of the melt pool.

3. The method of claim 1 , wherein the first powder layer includes a cubic material.

4. The method of claim 1 , wherein the first powder layer includes iron, nickel, or cobalt.

5. The method of claim 1 , wherein: the first patterned layer overlays a previous patterned layer; a cubic crystal structure is in the first patterned layer and is in the previous patterned layer; and the cubic crystal structure includes the dendrite that has a growth direction that is in the dendrite growth direction.

6. The method of claim 1 , further including: depositing a second powder layer on the first patterned layer; andproducing a second patterned layer by moving the melt pool in the second powder layer along a second layer scan pattern that includes a plurality of second layer scan lines, wherein the melt pool in the second powder layer has a pool depth that discourages the dendrite growth direction in the first patterned layer from being less than 45 degrees relative to a top surface of the melt pool.

7. The method of claim 6, wherein the dendrite growth direction in the first patterned layer is the same as the dendrite growth direction in the second patterned layer.

8. The method of claim 6, wherein the dendrite growth direction in the first patterned layer is perpendicular to the dendrite growth direction in the second patterned layer.

9. A system comprising: a powder bed; a powder feeder configured to deposit a plurality of powder layers by depositing a powder on the powder bed; a beam source configured to produce a melt pool in a topmost powder layer; and a beam scanner configured to produce a plurality of patterned layers from the powder layers by moving the melt pool relative to the powder bed, wherein: the powder layers include a first powder layer; a first one of the patterned layers is produced by moving the melt pool in the first powder layer along a first layer scan pattern that includes a plurality of scan lines; the scan lines are parallel and spaced by a hatch distance along a hatch direction that is perpendicular to the scan lines; a dendrite grows in a dendrite growth direction where the melt pool cools; the first layer scan pattern promotes the dendrite growth direction being orthogonal to the scan lines; and the hatch distance discourages the dendrite growth direction from having a directional component that is opposite the hatch direction.

10. The system of claim 9, wherein the hatch distance promotes the dendrite growth direction being at 45 degrees relative to a top surface of the melt pool.1 1 . The system of claim 9, wherein the powder includes a cubic material.

12. The system of claim 9, wherein the powder has iron, nickel, or cobalt.

13. The system of claim 9, wherein: the first one of the patterned layers overlays a previous patterned layer; a cubic crystal structure is in the first one of the patterned layers and is in the previous patterned layer; and the cubic crystal structure includes the dendrite.

14. The system of claim 9, wherein: the powder layers include a second powder layer on top of the first powder layer; and a second one of the patterned layers is produced by moving the melt pool in the second powder layer along a second layer scan pattern that includes a plurality of second layer scan lines, wherein the melt pool in the second powder layer has a pool depth that discourages the dendrite growth direction in the first one of the patterned layers from being less than 45 degrees relative to a top surface of the melt pool.

15. The system of claim 14, wherein the dendrite growth direction in the first one of the patterned layers is the same as the dendrite growth direction in the second one of the patterned layers.

16. The system of claim 14, wherein the dendrite growth direction in the first one of the patterned layers is perpendicular to the dendrite growth direction in the second one of the patterned layers.

17. The system of claim 9, further including: the plurality of patterned layers; and a cubic crystal structure that extends from the first one of the patterned layers to a second one of the patterned layers, wherein:the patterned layers, the cubic crystal structure, and the dendrite include a cubic material; and the cubic crystal structure includes the dendrite.

18. A system comprising: a plurality of patterned layers of a cubic material; and a cubic crystal structure that extends from a first one of the patterned layers to a second one of the patterned layers, wherein: each one of the patterned layers is formed by moving a melt pool in a scan pattern that includes a plurality of scan lines; and the cubic crystal structure includes a dendrite that has a long axis that is orthogonal to the scan lines.

19. The system of claim 18, wherein the cubic material includes iron, nickel, or cobalt.

20. The system of claim 19, wherein: at least one additional patterned layer is between the first one of the patterned layers and the second one of the patterned layers; and the first one of the patterned layers is at least 10 mm from the second one of the patterned layers.

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