Patent Application
20180258516
The disclosure relates to Ni—Nb—P—B alloys bearing low fractions of Cr and optionally Si that are capable of forming a metallic glass in bulk dimensions, and wherein the metallic glasses demonstrates a high toughness.
Ni—Cr—Nb—P—B alloys optionally bearing Si capable of forming bulk metallic glass rods with critical rod diameters greater than 3 mm have been disclosed in U.S. patent application Ser. No. 13/592,095, entitled “Bulk Nickel-Based Chromium and Phosphorus Bearing Metallic Glasses,” filed on Aug. 22, 2012, and issued as U.S. Pat. No. 9,085,814 on Jul. 21, 2015, the disclosure of which is incorporated herein by reference in its entirety. In this application it is also shown that within the disclosed range the toughness varies with the Cr content, attaining a peak of 94.56 MPa m1/2 over a very narrow range around 5 atomic percent Cr. The toughness drops significantly when the Cr content varies above or below the 5 atomic percent. This peak in toughness however comes at the expense of glass-forming ability, as the single alloy demonstrating the peak toughness has a critical rod diameter of just 5 mm.
Ni—Cr—Nb—P—B alloys optionally bearing Si capable of forming bulk metallic glass rods with critical rod diameters of at least 3 mm have been disclosed in U.S. patent application Ser. No. 14/540,815, entitled “Bulk Nickel-Chromium-Phosphorus Glasses Bearing Niobium and Boron Exhibiting High Strength and/or High Thermal Stability of the Supercooled Liquid Region,” filed on Nov. 13, 2014 and issued as U.S. Pat. No. 9,863,024 on Jan. 8, 2018, the disclosure of which is incorporated herein by reference in its entirety. In this application it is also shown that toughness increases as the atomic concentration of B drops below 3 atomic percent, but the increase in toughness comes at the expense of glass-forming ability. Specifically, a very narrow range is presented where notch toughness and critical rod diameter are both high, where a single alloy demonstrates a notch toughness of 95.1 MPa m1/2 and a critical rod diameter of 6 mm. When the B content varies above or below that value, either toughness or glass-forming ability drops significantly.
Ni—Cr—Nb—P—B alloys optionally bearing Si capable of forming bulk metallic glass rods have also been disclosed in U.S. patent application Ser. No. 14/067,521, entitled “Bulk Nickel-Based Chromium and Phosphorus Bearing Metallic Glasses with High Toughness,” filed on Oct. 30, 2013, the disclosure of which is incorporated herein by reference in its entirety. A combination of high glass-forming ability and high toughness is achieved within a range of Nb and Cr concentrations, where critical rod diameters exceed 6 mm and notch toughness values exceed 70 MPa m1/2. Alloys in the disclosed range demonstrate a notch toughness greater than 70 MPa m1/2 and up to 85.5 MPa m1/2, and a critical rod diameter greater than 6 mm and up to 11 mm.
The Ser. Nos. 13/592,095 and 14/540,815 applications therefore disclose Ni—Cr—Nb—P—B alloys optionally bearing Si with toughness varying sharply with composition, demonstrating a peak of about 95 MPa m1/2 over a very narrow range, while the alloys that demonstrate the peak toughness of about 95 MPa m1/2 have a critical rod diameter limited to 5-6 mm. On the other hand, the Ser. No. 14/067,521 application discloses Ni—Cr—Nb—P—B alloys optionally bearing Si that have both a high toughness and a high glass-forming ability over a broader region. While the glass-forming ability extends to as high as 11 mm, the notch toughness is limited to about 85 MPa m1/2.
There still remains a need to identify a compositional range of Ni—Cr—Nb—P—B alloys optionally bearing Si where the alloys demonstrate very high toughness and good glass-forming ability over a fairly broad compositional range.
The disclosure is directed to Ni—Cr—Nb—P—B alloys and metallic glasses, where over the disclosed range the alloys demonstrate good glass-forming ability while the metallic glasses formed from the alloys demonstrate a high toughness. Specifically, the alloys of the disclosure demonstrate a critical rod diameter in excess of 5 mm, while the metallic glasses formed from the alloys demonstrate a notch toughness greater than 95 MPa m1/2.
In one embodiment, the disclosure is directed to an alloy capable of forming a metallic glass represented by the following formula (subscripts w, x, y, and z denote deviations from a nominal concentration in atomic percentages, while a denotes an atomic fraction):
Ni(95−w−x−y−z)Cr2+wNb3+x(P1−aSia)yBz Eq. (1)
where:
In another embodiment, −1≤w<0.5.
In another embodiment, −0.5≤w<0.5.
In another embodiment, −0.4≤x≤0.8.
In another embodiment, −0.3×0.6.
In another embodiment, −2.7≤z≤3.8.
In another embodiment, −2.8≤z≤3.8.
In another embodiment, 20.2+0.2w−0.65|x|−z≤y≤20.7−z.
In another embodiment, 20.2+0.2w−0.65|x|−z≤y≤20.6−z.
In another embodiment, 0≤a≤0.8.
In another embodiment, 0≤a≤0.6.
In another embodiment, up to 2 atomic percent of Ni is substituted by Co, Fe, Cu, Ru, Re, Pd, Pt, or a combination thereof.
In another embodiment, up to 1 atomic percent of Cr is substituted by Mn, W, Mo, or a combination thereof.
In another embodiment, up to 1.5 atomic percent of Nb is substituted by Ta, V, or a combination thereof.
In another embodiment, the disclosure is directed to an alloy capable of forming a metallic glass comprising:
Cr in an atomic percent of 2 with a variance w of from −1.5 to less than 0.5;
Nb in an atomic percent of 3 with a variance x of from −0.5 to 1;
B in an atomic percent z ranging from 2.6 to 4;
P and optionally Si, where the combined P and Si atomic percent ranges from 20.2+0.2w−0.65|x|−z to 20.8−z, where the atomic fraction of Si in the combined P and Si atomic percent ranges from 0 to 0.1;
where the balance is Ni and incidental impurities;
where the critical rod diameter of the alloy is at least 5 mm; and
where the notch toughness of the metallic glass formed from the alloy is at least 96 MPa m1/2.
In some aspects, an alloy can include a small amount of incidental impurities. The impurity elements can be present, for example, as a byproduct of processing and manufacturing. The impurities can be less than or equal to about 2 wt %, alternatively less than or equal about 1 wt %, alternatively less than or equal about 0.5 wt %, alternatively less than or equal about 0.1 wt %.
In another embodiment, the alloy additionally comprises Co in an atomic fraction of up to 20%.
In another embodiment, up to 20 atomic percent of Ni is substituted by Co.
In another embodiment, the alloy additionally comprises Co, Fe, Cu, or combinations thereof, in an atomic fraction of up to 10%.
In another embodiment, up to 10 atomic percent of Ni is substituted by Co, Fe, Cu, or combinations thereof.
In another embodiment, the alloy additionally comprises Co, Fe, Mn, W, Mo, Ru, Re, Cu, Pd, Pt, Ta, V, or combinations thereof, in an atomic fraction of up to 2%.
In another embodiment, up to 2 atomic percent of Ni is substituted by Co, Fe, Cu, Ru, Re, Cu, Pd, Pt, or combinations thereof.
In another embodiment, up to 1 atomic percent of Cr is substituted by Mn, W, Mo, or combinations thereof.
In another embodiment, up to 1.5 atomic percent of Nb is substituted by Ta, V, or combinations thereof.
In another embodiment, the critical rod diameter of the alloy is at least 6 mm.
In another embodiment, the critical rod diameter of the alloy is at least 7 mm.
In another embodiment, the critical rod diameter of the alloy is at least 8 mm.
In another embodiment, the notch toughness of the metallic glass formed from the alloy is at least 96 MPa m1/2.
In another embodiment, the notch toughness of the metallic glass formed from the alloy is at least 97 MPa m1/2.
In another embodiment, the notch toughness of the metallic glass formed from the alloy is at least 98 MPa m1/2.
In another embodiment, the notch toughness of the metallic glass formed from the alloy is at least 99 MPa m1/2.
In another embodiment, the notch toughness of the metallic glass formed from the alloy is at least 100 MPa m1/2.
In another embodiment, the atomic concentration of Nb is less than 3.6 percent, and the notch toughness of the metallic glass formed from the alloy is at least 100 MPa m1/2.
In another embodiment, the atomic concentration of B is less than 3.8 percent, and the notch toughness of the metallic glass formed from the alloy is at least 100 MPa m1/2.
In another embodiment, the atomic concentration of metalloids is in the range of 20 to 20.7 percent, and the notch toughness of the metallic glass formed from the alloy is at least 100 MPa m1/2.
In another embodiment, the atomic concentration of Cr is not more than 2 percent, and the notch toughness of the metallic glass formed from the alloy is at least 100 MPa m1/2.
The disclosure is also directed to an alloy capable of forming a metallic glass having compositions selected from a group consisting of Ni74.8Cr2Nb2.9P16.75Si0.26B3.3, Ni74.8Cr2Nb2.9P16.5Si0.5B3.3, Ni74.8Cr2Nb2.9P16.25Si0.75B3.3, Ni75Cr2Nb2.7P16.5Si0.5B3.3, Ni74.6Cr2Nb3.1 P16.5Si0.5 B3.3, Ni74.4Cr2Nb3.3P16.5Si0.5 B3.3, Ni74.2Cr2Nb3.5P16.5Si0.5 B3.3, Ni74Cr2Nb3.7P16.5Si0.5B3.3, Ni73.8Cr2Nb3.9P16.5Si0.5B3.3, Ni74.4Cr2Nb3.3P17.1Si0.5B2.7, Ni74.4Cr2Nb3.3 P16.9Si0.5 B2.9, Ni74.4Cr2Nb3.3P16.7Si0.5 B3.1, Ni74.4Cr2Nb3.3P16.3Si0.5B3.5, Ni74.4Cr2Nb3.3P16.1Si0.5B3.7, Ni74.4Cr2Nb3.3P15.9Si0.5 B3.9, Ni74.21 Cr2Nb3.29P16.66Si0.51 B3.33, Ni74.03Cr1.99 Nb3.28 P16.83Si0.51 B3.36 Ni75.4Cr1 Nb3.3 P16.5Si0.5B3.3, Ni74.9Cr1.5 Nb3.3 P16.5Si0.5 B3.3, and Ni74.4Cr2Nb3.3P16.5Si0.5B3.3.
The disclosure is further directed to a metallic glass having any of the above formulas and/or formed of any of the foregoing alloys.
In a further embodiment, a method is provided for forming an article of a metallic glass comprising an alloy according to the present disclosure. The method includes melting the alloy to form a molten alloy and subsequently quenching the molten alloy at a cooling rate sufficiently high to prevent crystallization of the alloy.
In yet another embodiment, the molten alloy is fluxed with a reducing agent prior to the quenching.
In yet another embodiment, the molten alloy is fluxed with boron oxide prior to the quenching.
In yet another embodiment, the temperature of the molten alloy prior to quenching is at least 100° C. above the liquidus temperature of the alloy.
In yet another embodiment, the temperature of the molten alloy prior to quenching is at least 1100° C.
Additional embodiments and features are set forth in part in the description that follows, and in part will become apparent to those skilled in the art upon examination of the specification or may be learned by the practice of the disclosed subject matter. A further understanding of the nature and advantages of the disclosure may be realized by reference to the remaining portions of the specification and the drawings, which forms a part of this disclosure.
The description will be more fully understood with reference to the following figures and data graphs, which are presented as various embodiments of the disclosure and should not be construed as a complete recitation of the scope of the disclosure, wherein:
The disclosure is directed to alloys, metallic glasses, and methods of making and using the same. In some aspects, the alloys are described as capable of forming metallic glasses having certain characteristics. It is intended, and will be understood by those skilled in the art, that the disclosure is also directed to metallic glasses formed of the disclosed alloys described herein.
The disclosure provides a range of Ni—Cr—Nb—P—B alloys optionally bearing Si where the metallic glasses formed from the alloys demonstrate a notch toughness in excess of 95 MPa m1/2 and the alloys have a critical rod diameter in excess of 5 mm.
In the disclosure, the glass-forming ability of each alloy is quantified by the “critical rod diameter”, defined as maximum rod diameter in which the amorphous phase can be formed when processed by a method of water quenching a quartz tube with a 0.5 mm thick wall containing the molten alloy.
A “critical cooling rate”, which is defined as the cooling rate to avoid crystallization and form the amorphous phase of the alloy (i.e. a metallic glass), determines the “critical rod diameter.” The lower the critical cooling rate of an alloy, the larger its critical rod diameter. The critical cooling rate Rc in K/s and critical rod diameter in mm are related via the following approximate empirical formula:
R
c=1000/dc2 Eq. (2)
For example, according to Eq. (2), the critical cooling rate for an alloy having a critical rod diameter of about 3 mm is only about 102 K/s.
Generally, three categories are known in the art for identifying the ability of an alloy to form a metallic glass (i.e. to bypass the stable crystal phase and form an amorphous phase). Alloys having critical cooling rates in excess of 1012 K/s are typically referred to as non-glass formers, as it is very difficult to achieve such cooling rates and form the amorphous phase over a meaningful cross-section thickness (i.e. at least 1 micrometer). Alloys having critical cooling rates in the range of 105 to 1012 K/s are typically referred to as marginal glass formers, as they are able to form glass over thicknesses ranging from 1 to 100 micrometers according to Eq. (2). Alloys having critical cooling rates on the order of 103 or less, and as low as 1 or 0.1 K/s, are typically referred to as bulk glass formers, as they are able to form glass over thicknesses ranging from 1 millimeter to several centimeters. The glass-forming ability of an alloy (and by extension its critical cooling rate and critical rod diameter) is, to a very large extent, dependent on the composition of the alloy. The compositional ranges for alloys capable of forming marginal glass formers are considerably broader than those for forming bulk glass formers.
The notch toughness, defined as the stress intensity factor at crack initiation Kq, is the measure of the material's ability to resist fracture in the presence of a notch. The notch toughness is a measure of the work required to propagate a crack originating from a notch. A high Kq ensures that the material will be tough in the presence of defects.
The width of the supercooled region ΔTx is defined as the difference between the crystallization temperature Tx and the glass transition temperature Tg of the metallic glass, ΔTx=Tx−Tg, measured at heating rate of 20 K/min. A large ΔTx value implies a large thermal stability of the supercooled liquid and designates an ability of the metallic glass to be formed into an article by thermoplastic processing at temperatures above Tg.
Description of Alloy and Metallic Glass Compositions
In accordance with the provided disclosure and drawings, Ni—Cr—Nb—P—B alloys optionally bearing Si and metallic glasses formed from these alloys are provided within a well-defined compositional range requiring very low cooling rates to form metallic glasses, thereby allowing for bulk metallic glass formation such that metallic glass rods with critical rod diameters of at least 5 mm can be formed, and where the metallic glasses formed from the disclosed alloys demonstrate a notch toughness greater than 95 MPa m1/2.
Ni—Cr—Nb—P—B alloys optionally bearing Si that fall within the compositional ranges of the disclosure having a critical rod diameter of at least 5 mm forming metallic glasses that demonstrate notch toughness of at least 96 MPa m1/2 can be represented by the following formula (subscripts w, x, y, and z denote deviations from a nominal concentration in atomic percentages, while a denotes an atomic fraction):
Ni(95−w−x−y−z)Cr2+wNb3+x(P1−aSia)yBz Eq. (1)
Specific embodiments of metallic glasses formed of alloys having compositions according to the formula Ni74.8Cr2Nb2.9(P1−aSia)17B3.3, where a ranges from 0 to 1/17, are presented in Table 1. Note that parameter c in formula Ni74.8Cr2Nb2.9(P1−aSia)17B3.3 is equivalent to parameter a in Eq. (1). The corresponding critical rod diameters and notch toughness values are also listed in Table 1.
As shown in Table 2, the value for the metallic glass containing 0 atomic percent Si (Sample 1) is 38.9° C., while the value for the metallic glass containing 0.25 atomic percent Si (Sample 2) is 35.8° C. and the value for the metallic glass containing 0.5 atomic percent Si (Sample 2) is 37.3° C., which are smaller than the Si-free metallic glass (Sample 1). However, the value for the metallic glass containing 0.75 atomic percent Si (Sample 4) is 39.2° C., which is close to the Si-free metallic glass. The value for the metallic glass containing 1 atomic percent Si (Sample 5) drops to 37.1° C. For sample metallic glasses where the Si concentration is up to 1, ΔTx is at least 35° C.
Specific embodiments of metallic glasses formed of alloys having compositions according to the formula Ni74.7−xCr2Nb3+xP16.5Si0.5B3.3, where x ranges from −0.5 to +1.5, are presented in Table 3. The corresponding critical rod diameters and notch toughness values are also listed in Table 3.
As shown in Table 4, the value for the metallic glass containing 3.3 atomic percent Nb (Sample 9) is 36.7° C., and the value for the metallic glass containing 3.7 atomic percent Nb (Sample 11) is 40.5° C. The value for the metallic glass containing 4.1 atomic percent Nb (Sample 13) is 34.0° C., and the value for the metallic glass containing 4.5 atomic percent Nb (Sample 14) is 30.5° C. For sample metallic glasses where the Nb concentration is equal to or less than 4 atomic percent, ΔTx is at least 35° C.
Specific embodiments of metallic glasses formed of alloys having compositions according to the formula Ni74.4Cr2Nb3.3P19.8−zSi0.5Bz, where z ranges from 2.5 to 4.3, are presented in Table 5. The corresponding critical rod diameters and notch toughness values are also listed in Table 5.
As shown in Table 6, ΔTx values are larger when the B concentration exceeds 3.3 atomic percent compared to the ΔTx values associated with lower B concentrations. Specifically, the value for the metallic glass containing 2.5 atomic percent B (Sample 15) is 35.9° C., and the value for the metallic glass containing 2.9 atomic percent B (Sample 17) is 35.9° C., and the value for the metallic glass containing 3.3 atomic percent B (Sample 9) is 36.7° C. However, the value for the metallic glass containing 3.7 atomic percent B (Sample 20) is 41.2° C., and the value for the metallic glass containing 4.3 atomic percent B (Sample 23) is 41.9° C. For sample metallic glasses where the B concentration is in the range of 2.5 to 4 atomic percent, ΔTx is at least 35° C., while those where the B concentration is in is greater than 3.3 atomic percent, ΔTx is at least 40° C.
Specific embodiments of metallic glasses formed of alloys having compositions according to the formula [Ni0.933Cr0.025Nb0.042]100−y−z[P0.813Si0.025B0.162]y+z, where y+z (total metalloid concentration; i.e. the combined concentration of P, Si, and B) ranges from 19.5 to 20.9 atomic percent, are presented in Table 7. The corresponding critical rod diameters and notch toughness values are also listed in Table 7.
As shown in Table 8, ΔTx values unexpectedly increase when the total metalloid concentration is in the range of greater than 20.3 to 20.9 atomic percent, as compared to the values associated with metalloid concentrations in the range of 19.5 to 20.3 atomic percent. Specifically, the ΔTx values for the metallic glasses containing 19.5 to 20.3 atomic percent metalloids (Samples 24, 26, 9) is between 32.1° C. and 36.7° C., while the values for the metallic glasses containing 20.7 to 20.9 atomic percent metalloids (Samples 29, 30) is between 43.6° C. and 46.1° C. For sample metallic glasses where the metalloid concentration is greater than 20.5 atomic, ΔTx is at least 40° C.
Specific embodiments of metallic glasses formed of alloys having compositions according to the formula Ni74.4−wCr2+wNb3.3P16.5Si0.5B3.3, where w ranges from −2 to +3, are presented in Table 9. The corresponding critical rod diameters and notch toughness values are also listed in Table 9.
As shown in Table 10, the ΔTx value for the Cr-free metallic glass is 33.2° C., the value for the metallic glass containing 1 atomic percent Cr (Sample 32) is 37.1° C., the value for the metallic glass containing 2 atomic percent Cr (Sample 9) is 36.7° C., the value for the metallic glass containing 3 atomic percent Cr (Sample 35) is 38.1° C., and the value for the metallic glass containing 4 atomic percent Cr (Sample 36) is 38.8° C. For sample metallic glasses where the atomic concentration of Cr is in the range of 0.5 to 4 atomic percent, ΔTx is at least 35° C.
As seen in
Description of Methods of Processing the Sample Alloys
The particular method for producing the alloy ingots involves inductive melting of the appropriate amounts of elemental constituents in a quartz tube under inert atmosphere. The purity levels of the constituent elements were as follows: Ni 99.95%, Cr 99.8%, Nb 99.95%, P 99.999%, P 99.9999%, Si 99.9999%, and B 99.5%. The melting crucible may alternatively be a ceramic such as alumina or zirconia, graphite, sintered crystalline silica, or a water-cooled hearth made of copper or silver.
The particular method for producing the rods of sample metallic glasses from the alloy ingots involves re-melting the alloy ingots in quartz tubes having 0.5 mm thick walls in a furnace at 1350° C. under high purity argon and rapidly quenching in a room-temperature water bath. Alternatively, the bath could be ice water or oil. Metallic glass articles could be alternatively formed by injecting or pouring the molten alloy into a metal mold. The mold could be made of copper, brass, or steel, among other materials.
In some embodiments, prior to producing a metallic glass article, the alloyed ingots could be fluxed with a reducing agent by re-melting the ingots in a quartz tube under inert atmosphere, bringing the alloy melt in contact with the molten reducing agent, and allowing the two melts to interact for about 1000 s at a temperature of about 1200° C. or higher, and subsequently water quenching. In one embodiment, the reducing agent is boron oxide.
The glass-forming ability of each alloy was assessed by determining the maximum rod diameter in which the amorphous phase of the alloy (i.e. the metallic glass phase) could be formed when processed by the methods described above. X-ray diffraction with Cu-Kα radiation was performed to verify the amorphous structure of the alloys.
Test Methodology for Measuring Notch Toughness
The notch toughness of sample metallic glasses was performed on 3-mm diameter rods. The rods were notched using a wire saw with a root radius ranging from 0.10 to 0.13 mm to a depth of approximately half the rod diameter. The notched specimens were placed on a 3-point bending fixture with span of 12.7 mm, and carefully aligned with the notched side facing downward. The critical fracture load was measured by applying a monotonically increasing load at constant cross-head speed of 0.001 mm/s using a screw-driven testing frame. At least three tests were performed, and the variance between tests is included in the notch toughness plots. The stress intensity factor for the geometrical configuration employed here was evaluated using the analysis by Murakimi (Y. Murakami, Stress Intensity Factors Handbook, Vol. 2, Oxford: Pergamon Press, p. 666 (1987)).
Differential scanning calorimetry was performed on sample metallic glasses at a scan rate of 20 K/min to determine the glass-transition and crystallization temperatures of sample metallic glasses formed from the glass-forming alloys, and also determine solidus and liquidus temperatures of the alloys.
The combination of good glass-forming ability and high toughness exhibited by the metallic glasses of the disclosure make the present alloys and metallic glasses excellent candidates for various engineering applications. Among many applications, the disclosed alloys may be used in dental and medical implants and instruments, luxury goods, and sporting goods applications.
The alloys and metallic glasses described herein can also be valuable in the fabrication of electronic devices. An electronic device herein can refer to any electronic device known in the art. For example, it can be a telephone, such as a mobile phone, and a land-line phone, or any communication device, such as a smart phone, including, for example an iPhone®, and an electronic email sending/receiving device. It can be a part of a display, such as a digital display, a TV monitor, an electronic-book reader, a portable web-browser (e.g., iPad®), and a computer monitor. It can also be an entertainment device, including a portable DVD player, conventional DVD player, Blue-Ray disk player, video game console, music player, such as a portable music player (e.g., iPod®), etc. It can also be a part of a device that provides control, such as controlling the streaming of images, videos, sounds (e.g., Apple TV®), or it can be a remote control for an electronic device. It can be a part of a computer or its accessories, such as the hard drive tower housing or casing, laptop housing, laptop keyboard, laptop track pad, desktop keyboard, mouse, and speaker. The article can also be applied to a device such as a watch or a clock.
Having described several embodiments, it will be recognized by those skilled in the art that various modifications, alternative constructions, and equivalents may be used without departing from the spirit of the disclosure. Those skilled in the art will appreciate that the presently disclosed embodiments teach by way of example and not by limitation. Therefore, the matter contained in the above description or shown in the accompanying drawings should be interpreted as illustrative and not in a limiting sense. Additionally, a number of well-known processes and elements have not been described in order to avoid unnecessarily obscuring the disclosure.
The following claims are intended to cover all generic and specific features described herein, as well as all statements of the scope of the present method and system, which, as a matter of language, might be said to fall therebetween.
This patent application claims the benefit under 35 U.S.C. § 119(e) of U.S. Patent Application No. 62/469,348, entitled “BULK NICKEL-NIOBIUM-PHOSPHORUS-BORON GLASSES BEARING LOW FRACTIONS OF CHROMIUM AND EXHIBITING HIGH TOUGHNESS,” filed on Mar. 9, 2017, which is incorporated herein by reference in its entirety.
| Number | Date | Country | |
|---|---|---|---|
| 62469348 | Mar 2017 | US |
