FLEXIBLE BULK METALLIC GLASS ELEMENTS

Abstract

Flexible BMG elements and methods for making the flexible BMG elements. The BMG element contains a main body made from a BMG material and may further contain a flange. The main body may contain at least one opening. The main body may be a thin-walled structure that is compressible, extendable, and/or bendable. A surface of the main body may be corrugated with a series of ridges and furrows.

Claims

1. A flexible BMG element, the flexible element comprising: A main body with at least one opening, wherein the main body is made from a BMG material, and wherein the main body comprises a thin-walled structure that is compressible, extendable, and/or bendable.

2. The flexible BMG element of claim 1, wherein the main body comprises a cylindrical component, wherein a surface of the cylindrical component is corrugated.

3. The flexible BMG element of claim 1, wherein the main body comprises a thin-walled polygon-shaped component, wherein a surface of the component is corrugated.

4. The flexible BMG element of claim 1, wherein the main body is a thin-walled cylindrical component, wherein a surface of the cylindrical component is a repeating pattern of fine meshes such that the repeating pattern facilitates the bending of the main body.

5. The flexible BMG component of claim 4, wherein the main body has an inner diameter less than or equal to 6 mm and wherein the main body is biocompatible and configured to be inserted in a human body.

6. The flexible BMG element of claim 1, wherein the main body has a length-to-outer diameter ratio between 0.25 and 80.

7. The flexible BMG element of claim 1, wherein the main body has an outer diameter-to-wall thickness ratio larger than 8.

8. The flexible BMG element of claim 1, wherein the main body has a wall thickness between 0.0005 mm and 3 mm.

9. The flexible BMG element of claim 1, wherein the BMG material used to manufacture the main body has formability of 3 mm or higher.

10. The flexible BMG element in claim 1, wherein the main body comprises a non-flexible component.

11. The flexible BMG element of claim 1, wherein a wall thickness uniformity of the main body is under 35% or above 50%, wherein the wall thickness uniformity is defined by [(t.sub.max−t.sub.min)/t.sub.min]*100, wherein t.sub.max and t.sub.min are the maximum and the minimum wall thickness, respectively.

12. The BMG flexible element in claim 1, wherein the main body comprises a corrugated portion and the outer diameter of the corrugated portion is not constant along a length direction.

13. The BMG flexible element in claim 1, wherein the main body comprises an origami structure, comprising a crease configured to fold the main body.

14. The flexible BMG element of claim 1, wherein the flexible BMG element is a bellow, a flexible hose, an expansion joint, or a medical stent.

15. The flexible BMG element of claim 1, wherein the flexible BMG element is used to store and/or transfer media.

16. The flexible BMG element of claim 1, wherein the BMG material comprises, as a constituent element, one or more of: Zr, Ti, Ni, Pd, Mg, Al, La, Ce, Fe, Pt, Nb, Ir, Mo, W, Cu, Au, Ag, Hf, Co, Gd, Be, B, C, P, Si, and Rh.

17. The flexible BMG element of claim 1, wherein the BMG material is one of: Zr.sub.44Ti.sub.11Cu.sub.10Ni.sub.10Be.sub.25, Zr.sub.41Ti.sub.14Cu.sub.12.5Ni.sub.10Be.sub.22.5, Zr.sub.35Ti.sub.30Cu.sub.7.5Be.sub.27.5, Zr.sub.46Cu.sub.46Be.sub.8, Zr.sub.57Nb.sub.5Cu.sub.15.4Ni.sub.12.6Al.sub.10, Zr.sub.65Al.sub.10Ni.sub.10Cu.sub.15, Zr.sub.65Al.sub.7.5Ni.sub.10Cu.sub.12.5Ag.sub.5, Zr.sub.66.4Nb.sub.6.4Cu.sub.10.5Ni.sub.8.7Al.sub.8, Zr.sub.55Cu.sub.30Al.sub.10Ni.sub.5, Zr.sub.46Cu.sub.46Be.sub.8, Ti.sub.41Zr.sub.25Be.sub.28Fe.sub.6, Ti.sub.45Zr.sub.20Be.sub.29Fe.sub.6, Ti.sub.35Zr.sub.30Be.sub.25, Ti.sub.30Zr.sub.35Be.sub.25, Ti.sub.40Zr.sub.10Cu.sub.34Pd.sub.14Sn.sub.2, Ti.sub.40Zr.sub.10Cu.sub.32Pd.sub.14Sn.sub.4, Pd.sub.43Cu.sub.27Ni.sub.10P.sub.20, Pd.sub.40Ni.sub.10Cu.sub.30P.sub.20, Pd.sub.40Ni.sub.40P.sub.20, Pt.sub.57.5Ni.sub.14.7Cu.sub.5.3P.sub.22.5, Au.sub.49Ag.sub.5.5Pd.sub.2.3Cu.sub.26.9Si.sub.16.3, Ni.sub.45Pd.sub.35P.sub.17B.sub.3, Ni.sub.45Ti.sub.20Zr.sub.25Al.sub.10, Ni.sub.40Ti.sub.17Zr.sub.28Al.sub.10Cu.sub.5, Ni.sub.62Pd.sub.19Si.sub.2P.sub.17, Cu.sub.46Zr.sub.42Al.sub.7Y.sub.5, Mg.sub.65Cu.sub.25Y.sub.10, Mg.sub.65Cu.sub.7.5Ni.sub.7.5Zn.sub.5Ag.sub.5Y.sub.10, La.sub.55Al.sub.25Co.sub.5Cu.sub.10Ni.sub.5, Fe.sub.41Co.sub.7Cr.sub.15Mo.sub.14C.sub.15B.sub.6Y.sub.2 (in atomic percent), and a mixture thereof.

18. The flexible BMG element of claim 1, the flexible BMG element is made by forming steps comprising: contacting a BMG feedstock and a mold with a cavity and conducting thermoplastic forming to deform the BMG feedstock to replicate the shape of the cavity such that the flexible BMG element is seamless in entirety.

19. A flexible BMG element of claim 18, wherein 80% of the flexible BMG element is made through the thermoplastic forming, and wherein the thermoplastic forming is based on blow molding, hydroforming, compression molding, or a combination thereof.

20. The BMG flexible element of claim 18, wherein the thermoplastic forming step is followed by another thermoplastic forming step configured to further alter the shape of the BMG flexible element and/or improve the performance of the BMG flexible element, the performance being at least one of yield strength, elastic limit, and fatigue endurance.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0029] FIG. 1 shows a sketch of one example of the BMG flexible element of the present invention.

[0030] FIG. 2 shows a section A-A′ of the BMG flexible element of the present invention of FIG. 1.

[0031] FIG. 3 shows a sketch of one example of a BMG flexible element of the present invention with a main body having two openings with flanges on the two ends for connection to other systems.

[0032] FIG. 4 shows a sketch of one example of a BMG flexible element of the present invention with multiple corrugated sections.

[0033] FIGS. 5 shows a sketch of one example of a BMG flexible element of the present invention with a non-constant outer diameter in the corrugated section.

[0034] FIG. 6 shows a sketch of one example of a BMG flexible element of the present invention with a non-constant outer diameter in the corrugated section.

[0035] FIG. 7 shows a sketch of one example of a BMG flexible element of the present invention with a thin-walled, non-cylindrical shape.

[0036] FIG. 8 shows a sketch of one example of a BMG flexible element of the present invention with cylindrical tube or tube-like structure wherein its surface area feature is a repeating pattern of fine meshes.

[0037] FIG. 9 shows a sketch of one example of a BMG flexible element of the present invention with a corrugated section that is non-perpendicular to the main body's central axis.

[0038] FIG. 10 shows a flow chart for one example forming method of the BMG flexible element of the present invention of the present invention.

[0039] FIG. 11 shows a sketch of the contact between a feedstock and a mold.

DETAILED DESCRIPTION OF THE INVENTION

[0040] The present invention relates to a flexible BMG element. The flexible BMG element comprises a main body made from a BMG material and may further comprise a flange. The main body may comprise at least one opening. The main body may be a thin-walled structure that is compressible, extendable, and/or bendable.

[0041] The flexible element may have flanges on one or more ends, with a purpose to be connected to assemble with another system. The flexible BMG elements may be free of welded joints in their entirety. The flexible BMG elements may have a geometry of a tube with three or more sided tubes, including a cylinder. It can also be conical and have at least one broken symmetry.

[0042] The flexible BMG elements may have an inherent ductile state, a state at which the BMG's fictive temperature is greater than the critical fictive temperature (T.sub.f>T.sub.f.sup.c). The fictive temperature is used to characterize the glassy state and the critical fictive temperature is a temperature above which the BMG can deform in a ductile manner. The flexible BMG element may have Young's modulus greater than 10 GPa and yield strength greater than 1200 MPa. The flexible BMG elements may have one or more rotational symmetry along a single axis.

[0043] The flexible BMG element may be used to store and/or transfer media. The media may be in the state of gas, liquid, being compressed, or a combination thereof. The media may be air, oxygen, nitrogen, hydrogen, argon, helium, gasoline, or a combination thereof, including compressed hydrogen and cryo-compressed gas.

[0044] The flexible BMG elements may be produced through the thermoplastic forming (TPF) process. The TPF may be performed below 800° C., preferably below 700° C. The flexible BMG elements may be thin-walled, hollow shaped, essentially free of welded joints in contrast to conventional metal flexible elements. The BMG flexible element of present invention has one or more openings and can contain a pressurized fluid or gas while at least one of the opening is connected to another component of a system or a subsystem. The BMG flexible elements can be formed through a TPF process in the BMG's supercooled liquid state, and, as a result, the BMG flexible elements have crystallinity of less than 10%. It has been known in the art that BMG materials with crystallinity exceeding 10% suffers from properties deterioration, especially mechanically. A critical capability offered by the present invention is that the TPF-based BMG flexible elements are completely or essentially seamless and stress-free, has a uniform and consistent properties, and has a homogeneous glass state throughout the entire piece.

[0045] Moreover, the present inventors found that BMG flexible elements can be made from various BMG alloys but not all BMG alloys. Thermoplastic forming should be done at a low viscosity. However, only very few BMGs exhibit a low viscosity or more precisely a formability which also takes the available time into account. Particularly, BMG flexible element to be made through TPF-based manufacturing approach requires a BMG composition with a sufficient thermoplastic formability. The thermoplastic formability is a standard test used to measure the maximum strain a BMG can undergo in its supercooled liquid state before it eventually crystallizes. Particularly, the formability measures the maximum diameter to which the BMG can be deformed for a standardized set of processing parameters. With BMG with a low thermoplastic formability, the BMG does not have sufficient TPF-compatibility to deform through a TPF technique to achieve the BMG flexible element capturing the aspect ratio and wall thickness requirements. The required thermoplastic formability for the present invention is 3 mm or higher, preferably 6 mm or higher. Example BMG compositions for the present invention include Zr.sub.44Ti.sub.11Cu.sub.10Ni.sub.10Be.sub.25, Zr.sub.41Ti.sub.14Cu.sub.12.5Ni.sub.10Be.sub.22.5, Zr.sub.35Ti.sub.30Cu.sub.7.5Be.sub.27.5, Zr.sub.46Cu.sub.46Be.sub.8, Zr.sub.57Nb.sub.5Cu.sub.15.4Ni.sub.12.6Al.sub.10, Zr.sub.65Al.sub.10Ni.sub.10Cu.sub.15, Zr.sub.65Al.sub.7.5Ni.sub.10Cu.sub.12.5Ag.sub.5, Zr.sub.66.4Nb.sub.6.4Cu.sub.10.5Ni.sub.8.7Al.sub.8, Zr.sub.55Cu.sub.30Al.sub.10Ni.sub.5, Zr.sub.46Cu.sub.46Be.sub.8, Ti.sub.41Zr.sub.25Be.sub.28Fe.sub.6, Ti.sub.45Zr.sub.20Be.sub.29Fe.sub.6, Ti.sub.35Zr.sub.30Be.sub.25, Ti.sub.30Zr.sub.35Be.sub.25, Ti.sub.40Zr.sub.10Cu.sub.34Pd.sub.14Sn.sub.2, Ti.sub.40Zr.sub.10Cu.sub.32Pd.sub.14Sn.sub.4, Pd.sub.43Cu.sub.27Ni.sub.10P.sub.20, Pd.sub.40Ni.sub.10Cu.sub.30P.sub.20, Pd.sub.40Ni.sub.40P.sub.20, Pt.sub.57.5Ni.sub.14.7Cu.sub.5.3P.sub.22.5, Au.sub.49Ag.sub.5.5Pd.sub.2.3Cu.sub.26.9Si.sub.16.3, Ni.sub.45Pd.sub.35P.sub.17B.sub.3, Ni.sub.45Ti.sub.20Zr.sub.25Al.sub.10, Ni.sub.40Ti.sub.17Zr.sub.28Al.sub.10Cu.sub.5, Ni.sub.62Pd.sub.19Si.sub.2P.sub.17, Cu.sub.46Zr.sub.42Al.sub.7Y.sub.5, Mg.sub.65Cu.sub.25Y.sub.10, Mg.sub.65Cu.sub.7.5Ni.sub.7.5Zn.sub.5Ag.sub.5Y.sub.10, La.sub.55Al.sub.25Co.sub.5Cu.sub.10Ni.sub.5, Fe.sub.41Co.sub.7Cr.sub.15Mo.sub.14C.sub.15B.sub.6Y.sub.2.

[0046] The BMG material may comprise, as a constituent element, one or more of: Zr, Ti, Ni, Pd, Mg, Al, La, Ce, Fe, Pt, Nb, Ir, Mo, W, Cu, Au, Ag, Hf, Co, Gd, Be, B, C, P, Si, and Rh.

[0047] FIG. 1 shows a sketch of one example of a BMG flexible element. In one embodiment, the flexible element has a main body with two openings. The main body is made from a BMG material. The main body is a thin-walled cylindrical tube or it has a tube-like structure. The thin wall of the main body has a corrugated structure with a series of ridges and furrows. The BMG flexible element can be compressible, extendable, and bendable.

[0048] Section A-A′ in FIG. 2 shows a cross-section of the BMG flexible element highlighting its thin walls wherein the thickness is significantly smaller compared to the other dimensions. The wall thickness of the BMG flexible element may be between 0.0005 mm and 3 mm, more preferably between 0.025 and 0.5 mm. The BMG flexible element may have an outer diameter between 0.0055 mm and 500 mm, preferably 2 mm and 80 mm. The BMG flexible element may have a length-to-outer diameter ratio between 0.25 and 80. The corrugations may have a corrugation pitch-to-height between 0.05 and 10.

[0049] As shown in FIG. 3, the flexible element may have a main body with two openings and with flanges on the two ends for connection to other systems. The main body is made from a

[0050] BMG material. The flanges may be made from a BMG material, a non-BMG materials such as steel or stainless steel, or a combination of BMG and non-BMG materials. The main body has a thin-walled, cylindrical tube or tube-like structure. The thin wall of the main body has a corrugated structure with a series of ridges and furrows. The BMG flexible element can be compressible, extendable, and/or bendable in the corrugated sections.

[0051] As shown in FIG. 4, the BMG flexible element may have multiple corrugated sections in the main body that may be separated by a rigid non-corrugated section. The BMG flexible element may be compressible, extendable, and/or bendable in the corrugated sections.

[0052] As shown in FIGS. 5-6, the BMG flexible element may have a non-constant outer diameter in the corrugated section of the main body throughout its length.

[0053] As shown in FIG. 7, the main body may have a thin-walled, non-cylindrical shape, such as polygons, in the main body. The BMG flexible element may be an origami structure, including features and geometry that allow folding of the element such as creases and non-uniform thickness regions where thinner wall thickness regions allows folding of the structure, making the element flexible, compressible, extendable, and/or bendable.

[0054] As shown in FIG. 8, the main body may be hollow in majority and has a thin-walled, cylindrical tube or tube-like structure wherein its surface area feature is a repeating pattern of fine meshes such that the patterns facilitate the bending of the flexible element.

[0055] As shown in FIG. 9, the main body has a corrugated section that is non-perpendicular to the main body's central axis.

[0056] Referring to FIG. 10, one example forming method of the BMG flexible element of the present invention, thermoplastic forming (TPF), is described in a flowchart.

[0057] In the Step S1, a mold with a cavity with a negative feature of the desired BMG element and a BMG feedstock are provided. The shape of the cavity is selected according to the shape of the BMG flexible element to be formed. The mold may be made of one or more of various materials such as brass, steel, stainless steel, and non-metal such as alumina.

[0058] In the Step S2, the mold is heated up to a processing temperature, which is in a supercooled liquid region between the glass transition temperature and the crystallization temperature of the BMG feedstock. The BMG feedstock that is provided separately to the mold is placed on or into the mold cavity, covering the opening of the mold cavity, before or after the mold temperature reaches the processing temperature. The feedstock is heated into its processing temperature.

[0059] In the Step S3, after the temperature of the BMG feedstock reaches the processing temperature, which allows the BMG feedstock to become viscous and moldable, a pressure such as gas or liquid pressure is applied to the BMG feedstock such that the BMG feedstock deforms toward the surface of the cavity. The BMG feedstock deforms until reaching the surface of the cavity and replicating the shape of the cavity. The duration of deforming the BMG feedstock, the processing temperature, and the applied pressure are pre-determined to control the thickness, the crystallinity, and other properties of the BMG flexible element to be formed. The deformation duration is selected to be shorter than the amount of time that causes substantial crystallization such that the crystallinity of the BMG flexible element to be formed is minimized to be less than 10%.

[0060] In the Step S4, once the BMG feedstock completely fills the cavity of the mold, the deformed BMG is cooled below its glass transition temperature to form a solidified BMG flexible element.

[0061] In the Step S5, the BMG pressure vessel is removed from the mold.

[0062] In one working example, a Zr-based BMG flexible element is prepared following the steps described in the flow chart of FIG. 10. A steel mold with a negative feature of the desired BMG element is provided. The mold is heated into the supercooled liquid region of the Zr-based BMG alloy between 300° C. and 500° C. Then, the BMG feedstock is inserted into the mold cavity. Pressure between 5 to 500 psi is then applied onto the BMG material causing deformation of the BMG feedstock to replicate the features of the mold, forming the BMG flexible element. Then, the BMG flexible element is cooled below the glass transition temperature under 30° C. to solidify. The BMG flexible element is then removed from the mold.

[0063] The present inventors have found that a BMG flexible element especially ones with complex geometries such as a high aspect ratio or non-uniform wall thicknesses can be thermoplastically formed by controlling the contact area between the mold and the BMG feedstock. The mold-feedstock contact is defined by the surface area where the BMG material is under physical contact with the mold such as shown in FIG. 11. In traditional manufacturing techniques for traditional metals and BMGs, the feedstock-mold contact is high. For example, a mold and a die are assembled prior to manufacturing, leaving a small cavity for the liquid metal to flow into the channel to fabricate the desired element. The present inventors found that this approach cannot achieve the complex structures as described in the above embodiments. Surprisingly, the present inventors found that by minimizing the feedstock-mold contact and utilize external pressure to deform the BMG, a highly complex shapes including flexible elements with a high aspect ratio and engineered non-uniform wall thicknesses can be achieved.

[0064] Although only certain embodiments of this invention have been described in detail above, those skilled in the art will readily appreciate that many modifications are possible in the embodiments without materially departing from the novel teachings and advantages of the present invention. Accordingly, all such modifications are intended to be included within the scope of the present invention.