Patent Application
20180126456
Materials with extraordinary thermo-mechanical properties and radiation resistance can benefit a wide range of applications, such as nuclear fission and fusion reactors, nuclear waste containment, nuclear batteries, and space explorations. In these applications, radiation (e.g., He ions, electrons, neutrons, X-rays, gamma rays, etc.) can induce severe damages in materials, including swelling, hardening, creep, embrittlement, and irradiation-assisted corrosion. As a result, the tolerance of radiation damage (also referred to as radiation resistance) by structural materials can play a significant role in the safety and economy of nuclear energy, as well as the lifetime of nuclear batteries, spaceships and nuclear waste containers.
Conventional materials that are currently used in nuclear reactors (e.g., as fuel cladding) include, for example, zirconium and its alloys and austenitic stainless steels (SSs). However, their radiation resistance and mechanical stability at high temperatures are still limited and further improvement via traditional alloy development can be slow and expensive.
Embodiments of the present invention include metal-nanostructure composites and the methods of making and using the metal-nanostructure composites. In one embodiment, a method includes obtaining carbon nanotubes (CNTs) and encapsulating the CNTs with metal particles. The method also includes consolidating the encapsulated CNTs and forming the consolidated metal/CNTs so as to produce metal-nanostructure composites that can have superior radiation resistance (e.g., resistance to void swelling and embrittlement) and mechanical properties (e.g., strength and ductility). The CNTs can be encapsulated into the meal particles via atomic welding techniques such that the CNTs can maintain their free-standing configuration in the metal particles without significant deformation and collapse.
In another embodiment, a material includes a nanostructure-metal matrix composite. The nanostructure-metal matrix composite includes a metal and at least one nanofiller component dispersed in the grains of the metal. The nanofiller can include both one-dimensional nanostructures (e.g., nano-tubes, nano-rods, nano-pillars, etc.) and two-dimensional nanostructures (e.g., graphene, nano-foam, nano-mesh, etc.).
It should be appreciated that all combinations of the foregoing concepts and additional concepts discussed in greater detail below (provided such concepts are not mutually inconsistent) are contemplated as being part of the inventive subject matter disclosed herein. In particular, all combinations of claimed subject matter appearing at the end of this disclosure are contemplated as being part of the inventive subject matter disclosed herein. It should also be appreciated that terminology explicitly employed herein that also may appear in any disclosure incorporated by reference should be accorded a meaning most consistent with the particular concepts disclosed herein.
The skilled artisan will understand that the drawings primarily are for illustrative purposes and are not intended to limit the scope of the inventive subject matter described herein. The drawings are not necessarily to scale; in some instances, various aspects of the inventive subject matter disclosed herein may be shown exaggerated or enlarged in the drawings to facilitate an understanding of different features. In the drawings, like reference characters generally refer to like features (e.g., functionally similar and/or structurally similar elements).
Nano-structuring can be a promising approach to improve the radiation resistance of materials and address, at least partially, challenges in existing methods to develop radiation resistant materials. For example, carbon nanotubes (CNTs) are known to be mechanically robust and flexible. Without being bound by any particular theory or mode of operation, when CNTs are uniformly dispersed inside metal (also referred to as host metal) as 1D fillers, instead of only being attached to the metal surfaces, their high aspect ratio η (up to 108) can create prolific internal interfaces with the metal matrix. These internal interfaces may act as venues for the radiation defects to recombine (i.e., self-heal).
In addition, based on percolation theory and geometrical simulations, a random 3D network of 1D fillers can form globally percolating transport paths even with diminishing volume fraction ϕ→0, if η→1. The global percolating transport paths can also mitigate embrittlement and swelling. As understood in the art, embrittlement and swelling can be exacerbated by Helium (alpha particle) accumulation inside materials. The globally percolating paths formed by 1D fillers can function as “nano-chimneys” that can outgas the accumulated helium and other fission gases to an external fission-product gettering and/or trapping system, thereby mitigating embrittlement and swelling.
When used in nuclear reactors or other radiative environments, it can be helpful for the metal-CNT composite (MCC) to have the following properties. First, the dispersion of CNTs does not degrade thermo-mechanical properties (strength, toughness, thermal conductivity, etc.) of the CNTs. In other words, CNTs can maintain their thermal-mechanical properties after dispersion. Second, under radiation, the dispersed CNTs can mitigate radiation embrittlement and swelling reduced (e.g., due to self-healing effect of the filler-metal interfaces) in MCC compared to a control metal without the dispersed CNTs. Third, the 1D nano-fillers themselves can also sustain heavy dose of radiation. For example, typical radiation exposure to the nuclear fuel cladding material is ˜15 DPA (displacements per atom) before they are taken out of the reactor. Core internals in commercial light-water reactors should sustain around 80 DPA after 40 years of plant operations, and advanced fast reactors would demand even more.
The properties of Al/CNT can depend on the modification of interfaces of 1D nanostructure upon irradiation. The energies of incoming ions are usually absorbed to transform CNT structure to rearranged carbon nanostructure, or aluminum carbide nanorods, depending on the ion type and beam energy. The 1D interfaces can reduce the supersaturation of radiation-generated vacancies, by boosting recombination with self-interstitial atoms (SIA) and interstitial clusters. Lightweight ion irradiation (e.g., He ion radiation) can generally generate more “sparse” collision cascades with lower defect density and shorter length compared to heavy ions. Therefore, He ion irradiation can cause less Al/C mixing than Al ion irradiation since an interstitial Al atom can quickly find the nearest vacancy of the same chemical species. The CNT under lightweight radiation can undergo restructuring and form a helical carbon nanostructure. Irradiation with heavier Al ions, which can produce “denser” collision cascades and more Al/C mixing, can change the composition of CNT fillers by forming an aluminum carbide phase with 1D nanorod morphology. To take advantage of the above processes for improving radiation resistance, uniform dispersion of CNTs within the host metal without degradation to CNTs or Al matrix can be the very beneficial.
The nano-structuring approach described in this application employs an atomic welding technique to uniformly disperse nanofillers (including 1D and 2D nanostructures) within host metals. In atomic welding, nanofillers can be initially disposed on surfaces of multiple metal particles. These metal particles can then merge together (e.g., through Ostwald ripening), thereby encapsulating the nanofillers within the resulting merged metal. For host metals having strong tendency of oxidation, the process can be performed in a glove box to prevent oxidation. In addition, a polar covalent coating can be applied on the nanofillers to increase wettability and facilitate the atomic welding.
These methods can allow mass-production of metal/carbon nanotube (CNT) composites that have improved radiation tolerance. The produced 0.5 wt % Al+CNT composite can have improved tensile strength without reduction of tensile ductility before radiation, and reduced void/pore generation and radiation embrittlement at high displacements per atom (DPA). Under helium ion irradiation up to 72 DPA, the 1D carbon nanostructures survive, while sp2 bonded graphene transforms to sp3 tetrahedral amorphous carbon. Self-ion (Al) irradiation can convert CNTs to a metastable form of Al4C3, which can maintain a slender configuration as 1D nano-rods, thereby preserving the prolific internal interfaces that can catalyze recombination of radiation defects and reduce radiation hardening and porosity generation. The 1D fillers may also form percolating paths of “nano-chimneys” that outgas the accumulated helium and other fission gases, addressing the gas accumulation problem.
The dispersion (also referred to as distribution) of the nanofillers 220 can have several features. First, each individual nanofiller 220 substantially maintains its free-standing form within the metal 210, in a similar manner like a leave preserved in a fossil, or an insect trapped in an amber. In other words, the dispersion process does not cause deformation or collapse of the individual nanofillers 220, thereby maintaining prolific interfaces between the nanofiller 220 and the metal 210.
Second, the nanofillers 220 are distributed within the metal 210 in a substantially uniform manner. For example, the average distance between neighboring nanofillers 220 (also referred to as inter-filler distance) can be about 100 nm and the fluctuation of inter-filler distance can bout about ±50 nm. In another example, the average inter-filler distance can be about 50 nm to about 1 μm and the fluctuation of inter-filler distance can be about ±25 nm to about ±500 nm. In yet another example, the average inter-filler distance can be about 75 nm to about 200 nm and the fluctuation of inter-filler distance can be about ±35 nm to about ±100 nm.
In addition, the nanofillers 220 do not create grain boundary flocculation of the metal 210. The radiations damage such as void swelling and embrittlement usually occur from the vacancy and intestinal generation inside grain. Furthermore, the deformation of metal can also occur from dislocation movement inside grain. Nanofillers inside grain without having grain boundary flocculation can provide more chances to have interaction with vacancy, interstitial, and dislocations. This structure, therefore, can enhance the mechanical strength and radiation resistance.
The metal 210 can include various materials. In one example, the metal 210 includes aluminum (Al), which is cost-effective and very widely used. For example, Al can be used as the fuel cladding materials in research reactors, as well as containment for nuclear waste, components for robots in radiation environments, etc. Its light density may impart significant advantage for space applications. Al has low thermal neutron absorption cross-section of 0.232 barn, above only those of Mg (0.063 barn), Pb (0.171 barn) and Zr (0.184 barn) among structural metals, and high corrosion resistance in water, therefore it is already widely used in low-temperature research reactors. The development of Al/CNT may not only benefit research reactors, but also provide guidance for designing new kinds of cladding materials (e.g., Zr+=/CNT, Stainless steel/CNT) that can be used in commercial reactors. Second, Al is used in nuclear battery since it is reflective, and has low production rate of Bremsstrahlung radiation due to low atomic number. Thus it has been recommended for several components in designs of nuclear battery such as shielding, current collector, and electrode. Al+CNT will increase the lifetime of nuclear battery because of better radiation resistance. This composite may also alleviate helium accumulation from alpha decay, which is one of the main engineering issues associated with radioisotope thermoelectric generator (RTG).
In another example, the metal 210 includes gold (Au), which is highly resistant to oxidation in air and water and widely used in electronics and jewelry industry. Dispersing nanofillers 220 within gold can increase the wear resistance (e.g., resistance to scratch or other mechanical damages). In yet another example, the metal 210 includes iron, which can be useful in nuclear reactors due to its mechanical stability. In yet another example, the metal 210 can include other materials such as Magnesium (Mg), Zirconium (Zr), Copper (Cu), Silver (Ag), and Platinum (Pt), among others.
In yet another example, the metal 210 can include more than one metal element or alloys. Table 1 below shows the composition (at %) of one Al alloy that can be used to make the composite 200.
The nanofillers 220 can also employ various types of nanostructures. In general, it can be helpful for the nanofillers 220 to produce abundant interfaces with the metal 210 when dispersed in the metal 210. To this end, the nanofillers 220 can have a large surface area to volume ratio. In general, a larger surface area to volume ratio is more beneficial in creating interfaces with the metal.
In one example, the nanofillers 220 include one-dimensional (1D) nanostructures such as nanotube (e.g., carbon nanotube, multiwall carbon nanotube, etc.), nano-rod, nano-pillar, nano-wire, nano-fiber, and nano-ribbon, among others. The aspect ratio of these 1D nanostructures can be greater than 100, greater than 1000, greater than 104, greater than 105, and even higher (e.g., about 108 for carbon nanotubes made from a single-atom layer). For example, multiwall carbon nanotubes (MWCNTs) can be used as the nanofillers 220. The diameter D of the MWCNTs can be about 10 nm to about 30 nm and the length L of the MWCNTs can about 10 μm, creating an aspect ratio η˜L/D of about 300-1000.
In another example, the nanofillers 220 include two-dimensional (2D) nanostructures such as nano-sheet (e.g., single layer graphene, double-layer graphene, multilayer graphene, etc.), nano-mesh, and nano-foam, among others.
The nanostructures in the nanofillers 220 can be made of various elements. In one example, the nanofillers 220 include carbon nanostructures such as carbon nanotubes, graphene, or any other carbon nanostructure known in the art. In another example, the nanofillers 220 include other elements such as oxygen (O), silicon (Si), boron (B), and nitrogen (N). In yet another example, the nanofillers 220 can include more than one element. For example, the nanofillers 220 can include a carbon nanostructure doped with another element such as silicon, nitrogen, oxygen, and boron, among others.
The nanofillers 220 can further includes a polar covalent coating to increase the wettability of the nanofillers 220, thereby facilitating the dispersion of nanofillers 220 within the metal 210. In one example, the polar covalent coating includes silicon carbide (SiC). In another example, the polar covalent coating includes silicon oxide (SiOx). In yet another example, the polar covalent coating can include materials such as oxygen compound, boron compound, nitrogen compound, and/or carbon compound.
In some examples, the encapsulation process can be performed in a glove box (e.g., manufactured by M.O. Tech, Korea) to prevent oxidation. The glove box can create an inert atmosphere, which includes a gaseous mixture that contains little or no oxygen and primarily consists of non-reactive gases or gases that have a high threshold before they react. Example non-reactive gases include nitrogen, argon, helium, carbon dioxide, or any other non-reactive gas known in the art. The oxygen and moisture level can be set at, for example, below 1 ppm.
The encapsulated CNTs 320 and metal 310 can be consolidated to create Al—C covalent bonds. The consolidation can be carried out by a spark plasma sintering process, also referred to as field assisted sintering technique (FAST) or pulsed electric current sintering (PECS). In one example, the spark plasma sintering (e.g., SPS, 50 t, 50 kW, Eltek, Korea) can be performed, for example, under a pressure 40 MPa at 560° C. for 15 min.
The method 300 shown in
The method 300 uses aluminum as the host metal and carbon nanotubes as the nanofillers for illustrating purposes. In practice, the method 300 can be adapted to manufacture other metal-nanostructure composites as described in previous sections.
The methods 300 and 400 illustrated in
Characterization of Metal-Nanostructure Composites
This section describes characterizations of example metal-nanostructure composites, such as Al/CNT composites, using a high-energy ion accelerator to inject He and Al ions that can generate atomic displacements in the composites, in lieu of neutrons. The CNTs dispersed in Al can maintain their thermo-mechanical properties and mitigate embrittlement and swelling problems in the resulting Al/CNT composite. In addition, the 1D form factor of nano-fillers can also sustain 72 DPA of He ion irradiation and 72 DPA of Al self-ion radiations at room temperature. These experimental results are unexpected and surprising because every carbon and aluminum atoms are knocked out about 102 times under the radiation level, yet the 1D nano-morphologies are preserved, along with the prolific internal interfaces. The morphological robustness of 1D nano-fillers in non-equilibrium conditions can be reminiscent of nanowire growth in chemical vapor deposition that violates equilibrium Wulff construction. The accelerator-based ion irradiation tests can be performed at room temperature (homologous temperature T/TM=0.32, Al's melting point is TM=933.47 K). At this range, volumetric swelling from void formation can be prominent when radiation exposure is larger than 10 DPA, and thereby allowing convenient study of radiation resistance.
These images show that CNTs are embedded inside the Al grain (e.g., as indicated by the white arrow in
Ion radiation tests are also performed on Al/CNTs composites to show improved radiation resistance of these composites. More specifically, extruded 2.5 mm of control Al and Al/CNTs wire (e.g., see
Without being bound by any particular theory or mode of operation, if the CNTs are entirely straight and randomly distributed, then analytical modeling and Monte Carlo simulations gives percolation threshold estimate:
which for an aspect ratio η˜L/D=300, gives ϕc=0.0016, and for η˜L/D=1000, gives ϕc=5×10−4. The CNT volume fraction as used in samples here is an order of magnitude larger than φc. Therefore, the CNTs can form a globally percolating network of nano-chimneys. Any helium gas is expected to travel facilely in 1D hollow structure like CNTs with smooth interior walls.
To test the radiation tolerance of the Al/CNT composites, the samples are irradiated by 100 keV helium ions and 2 MeV aluminum self-ion up to 3.6, 16 and 72 DPA, respectively. The results are compared with the pure Al control samples under the same irradiation conditions.
The noticeable reduction of porosity in Al/CNTs composites also implies that He gas can readily diffuse out of Al matrix. Two mechanisms are possibly. First, Helium gas can diffuse out along the CNT-metal interface. Second, the interspace and central hollow space inside CNTs can act as pathways (e.g., “nano-chimneys”) for He gas to transport out of the metal. Since the mechanical strength is enhanced significantly by load transfer associated with strong anchoring of Al onto the CNT surface, it is more likely that the second mechanism is responsible for the helium gas diffusion.
The microstructure of the helium ion irradiated samples can be further characterized by high-resolution TEM (e.g., HRTEM, 200 keV, 2010F, manufactured by JEOL). The TEM sample can be prepared using focused ion beam (e.g., FIB, Helios Nanolab 6000, FEI) with a Ga ion milling process and a Pt protection layer. The sample can be cut from the surface because helium ion penetration depth is usually less than 1 um. The cavities in all the samples can be determined by under/over focusing under TEM. The sizes and cavities can be characterized by measuring diameter of all the cavities according to the depth. The average diameters of cavities versus depth can be calculated by area-weighted average diameter:
To quantify the effects of CNTs on the radiation damage induced by He ion irradiation in the Al, the stopping and range of ions in matter (e.g., SRIM-2013) simulation (see, e.g., srim.org) can be performed with and without carbon element in the Al matrix. The carbon content of Al+1 vol % CNT can be roughly 0.5 wt %. In the simulation, carbon atoms can be uniformly dispersed in the Al matrix to extract the effect of the carbon atoms alone. The maximum DPA is predicted to occur at 534 nm in depth, slightly shallower than the maximum peak (596 nm) of injected He ion.
If the CNTs are randomly dispersed, the furthest distance between any point of its nearest CNTs can scale as Lfurthest ∝Dϕ−1/2 (D=diameter). For 1 vol % MWCNT sample, Lfurthest is around 200 nm, which is still an order of magnitude longer than the typical size of a radiation cascade, which is about 10-20 nm. Therefore, the improvement in porosity suggests that porosity development involves length scales quite beyond a single cascade annealing. For comparison, ultra-fine grained austenitic stainless steel with a grain size of 100 nm can exhibit 5 times slower void swelling rate up to 80 DPA, and Lfurthest in that case is 50 nm if all the grain boundaries (GB) are effective venues for recombination. Compared to that system of “2D nano-engineered” network of GBs, the “1D nano-engineered” CNTs/Al composite described herein has 4 times longer Lfurthest and 15 times less interfacial area per volume. Yet the composite can achieve similar performance in cavity suppression.
The surface mechanical properties of Al/CNTs composites can be characterized by Knoop hardness (e.g., LM 248 AT, LECO, USA). The test can be carried out under a 10 g force for 10 seconds to study the response of sample surface to the force.
HK=14229×P/d2 (3)
where P is force in gf, and d is length of long diagonal in μm.
However, once above 3.6 DPA, the Knoop hardness of control Al decreases with increasing helium ion irradiation dose. This phenomenon could be explained by the severe porosity development which reduced the apparent density of materials. The cavity volume fraction in control Al reached 25% at 72 DPA (e.g., see
The CNTs in the Al matrix can be further characterized using confocal Raman spectroscopy techniques at 785 nm excitation. In addition, Raman spectroscopy (e.g., Reinshaw, UK) of reference aluminum carbide (Al4C3, 98%, 325 mesh, sigma-aldrich) can be measured at 633 nm excitation.
The temperature mapping in
The sp3/sp2 mapping results (
In reference to pure Al and graphite, the Gibbs free energy of formation for the stable phase of Al4C3 (rhombohedral) is about −194.4 kJ/mol at room temperature or −2.01 eV per Al4C3 unit formula. On a per carbon basis, it is not as high as that for ZrC (−2.14 eV per ZrC), but is comparable to SiC (−0.76 eV per SiC) and much higher than cementite (−0.18 eV per Fe3C). So the fact that much of the carbon nanostructures survive without forming the carbide after 72 DPA He-ion irradiation is unexpected and surprising. On the other hand, the conversion of sp2 bonding of carbon in CNTs to sp3 of ta-C agrees with the previous understanding of radiation damage of carbon.
To further study the compositions of the Al/CNTs composites after radiation, Vienna Ab-initio Simulation Package (VASP) can be employed to compute the structure of Al4C3. Calculations can be carried out using generalized gradient approximation (GGA) in the PBE form for the exchange-correlation functional. To ensure convergence, 520 eV plane wave cutoff and 20×20×20 Monkhorst-Pack grid can be adopted. Calculation parameters are summarized in Table 3 below.
Aluminum self-ion irradiation with higher energy of 2 MeV (20× that of helium ion) which creates denser cascades can eventually disintegrate the pure carbon nanostructure and generate slender Al4C3 nanocarbides, as seen in
Many distinct lattice orientation relationships are also present between the newly formed Al4C3 and Al matrix, with semi-coherent and incoherent interfaces based on high-resolution TEM observations. The 1D nanocarbides can likely benefit energetically from the interfacial energy considerations with the matrix, which otherwise would be considered high energy in bulk form.
In the jewelry market, the use of 24 k gold can be limited because it is soft and easily worn by scratches. In contrast, Au/carbon composites described herein can add mechanical stability and wear resistance to the gold with minimum cost increase. The Au/carbon composite can enable the use of 24 k gold as jewelry materials adding more degree of freedom to the design. The improved mechanical property and the wear resistance of the Au/carbon composite are also useful for electric connections improving the lifetime of the products.
In the Au/carbon composite, carbon nanostructures is introduced into the gold grain, forming two phase composite structure, which can have special advantage to improve significant mechanical properties such as the prevention of the dislocation propagation. Strong sp2 carbon-carbon bonding can resist the dislocation movement and enhance the mechanical properties. Furthermore, the carbon nanostructure inside grain can prevent the crack propagation, resulting in improvement of the toughness.
Carbon is very light density compared to other metals such as Cu, Ag, Fe, Ni, Pb which are used to enhance the mechanical properties of the pure gold. Therefore, less than 0.5% of carbon can enhance the hardness level of 18 k gold to a noticeable extent.
The Au/carbon composite can be fabricated using methods similar to the methods 300 shown in
While various inventive embodiments have been described and illustrated herein, those of ordinary skill in the art will readily envision a variety of other means and/or structures for performing the function and/or obtaining the results and/or one or more of the advantages described herein, and each of such variations and/or modifications is deemed to be within the scope of the inventive embodiments described herein. More generally, those skilled in the art will readily appreciate that all methods, dimensions, materials, and configurations described herein are meant to be exemplary and that the actual methods, dimensions, materials, and/or configurations will depend upon the specific application or applications for which the inventive teachings is/are used. Those skilled in the art will recognize, or be able to ascertain using no more than routine experimentation, many equivalents to the specific inventive embodiments described herein. It is, therefore, to be understood that the foregoing embodiments are presented by way of example only and that, within the scope of the appended claims and equivalents thereto, inventive embodiments may be practiced otherwise than as specifically described and claimed. Inventive embodiments of the present disclosure are directed to each individual feature, article, material, and/or method described herein. In addition, any combination of two or more such features, systems, articles, materials, kits, and/or methods, if such features, systems, articles, materials, and/or methods are not mutually inconsistent, is included within the inventive scope of the present disclosure.
Also, various inventive concepts may be embodied as one or more methods, of which examples have been provided. The acts performed as part of the method may be ordered in any suitable way. Accordingly, embodiments may be constructed in which acts are performed in an order different than illustrated, which may include performing some acts simultaneously, even though shown as sequential acts in illustrative embodiments.
All definitions, as defined and used herein, should be understood to control over dictionary definitions, definitions in documents incorporated by reference, and/or ordinary meanings of the defined terms.
The indefinite articles “a” and “an,” as used herein in the specification and in the claims, unless clearly indicated to the contrary, should be understood to mean “at least one.”
The phrase “and/or,” as used herein in the specification and in the claims, should be understood to mean “either or both” of the elements so conjoined, i.e., elements that are conjunctively present in some cases and disjunctively present in other cases. Multiple elements listed with “and/or” should be construed in the same fashion, i.e., “one or more” of the elements so conjoined. Other elements may optionally be present other than the elements specifically identified by the “and/or” clause, whether related or unrelated to those elements specifically identified. Thus, as a non-limiting example, a reference to “A and/or B”, when used in conjunction with open-ended language such as “comprising” can refer, in one embodiment, to A only (optionally including elements other than B); in another embodiment, to B only (optionally including elements other than A); in yet another embodiment, to both A and B (optionally including other elements); etc.
As used herein in the specification and in the claims, “or” should be understood to have the same meaning as “and/or” as defined above. For example, when separating items in a list, “or” or “and/or” shall be interpreted as being inclusive, i.e., the inclusion of at least one, but also including more than one, of a number or list of elements, and, optionally, additional unlisted items. Only terms clearly indicated to the contrary, such as “only one of” or “exactly one of,” or, when used in the claims, “consisting of,” will refer to the inclusion of exactly one element of a number or list of elements. In general, the term “or” as used herein shall only be interpreted as indicating exclusive alternatives (i.e., “one or the other but not both”) when preceded by terms of exclusivity, such as “either,” “one of,” “only one of,” or “exactly one of” “Consisting essentially of,” when used in the claims, shall have its ordinary meaning as used in the field of patent law.
As used herein in the specification and in the claims, the phrase “at least one,” in reference to a list of one or more elements, should be understood to mean at least one element selected from any one or more of the elements in the list of elements, but not necessarily including at least one of each and every element specifically listed within the list of elements and not excluding any combinations of elements in the list of elements. This definition also allows that elements may optionally be present other than the elements specifically identified within the list of elements to which the phrase “at least one” refers, whether related or unrelated to those elements specifically identified. Thus, as a non-limiting example, “at least one of A and B” (or, equivalently, “at least one of A or B,” or, equivalently “at least one of A and/or B”) can refer, in one embodiment, to at least one, optionally including more than one, A, with no B present (and optionally including elements other than B); in another embodiment, to at least one, optionally including more than one, B, with no A present (and optionally including elements other than A); in yet another embodiment, to at least one, optionally including more than one, A, and at least one, optionally including more than one, B (and optionally including other elements); etc.
In the claims, as well as in the specification above, all transitional phrases such as “comprising,” “including,” “carrying,” “having,” “containing,” “involving,” “holding,” “composed of,” and the like are to be understood to be open-ended, i.e., to mean including but not limited to. Only the transitional phrases “consisting of” and “consisting essentially of” shall be closed or semi-closed transitional phrases, respectively, as set forth in the United States Patent Office Manual of Patent Examining Procedures, Section 2111.03.
This application is a continuation of International Application No. PCT/US16/21781, filed Mar. 10, 2016, entitled “Metal-Nanostructure Composites,” which in turn claims priority to and benefit of U.S. provisional application Ser. No. 62/130,766, filed Mar. 10, 2015, entitled “DISPERSION OF CARBON NANOTUBES IN METALS IMPROVES RADIATION RESISTANCE AND HELIUM RESISTANCE”; each of the aforementioned applications are hereby incorporated herein by reference in their entirety for all purposes.
| Number | Date | Country | |
|---|---|---|---|
| 62130766 | Mar 2015 | US |
| Number | Date | Country | |
|---|---|---|---|
| Parent | PCT/US2016/021781 | Mar 2016 | US |
| Child | 15699757 | US |
