Alkaline Earth Metal Stabilized Bulk Nanocrystalline Engineering Alloys
US20260043114A1
Abstract
A nano-structured alloy material includes a nanoparticle; a matrix phase surrounding the nanoparticle; and an alkali/alkali Earth metal (i) which is incorporated into the nanoparticle, (ii) which may also be incorporated into the matrix and therefore alter a material property of the matrix phase 120, and (iii) an interaction of the nanoparticle with the matrix phase.
Description (excerpt)
CROSS-REFERENCE TO RELATED APPLICATIONS U.S. Pat. No. 9,333,558, issued on May 10, 2016, U.S. Pat. No. 9,822,430, issued on Nov. 21, 2017, and U.S. Pat. No. 11,975,385, issued on May 7, 2024, are incorporated by reference herein. GOVERNMENT INTEREST The invention described herein may be manufactured, used and licensed by or for the U.S. Government. BACKGROUND OF THE INVENTION Existing nanocrystalline alloys may suffer performance degradation at high temperatures. Thus, there is a need for a nanocrystalline alloy that offers consistent or improved performance at high temperatures. BRIEF SUMMARY OF THE INVENTION Some embodiments of the invention may provide compounds, and ways to manufacture those compounds, that are able to form nanocrystalline alloys. In some embodiments, the alloys may include strontium (Sr) as an alloying element “X”. The nanocrystalline alloys may include various base metals, such as silver (Ag), aluminum (Al), gold (Au), cobalt (Co), chromium (Cr), copper (Cu), iron (Fe), hafnium (Hf), magnesium (Mg), molybdenum (Mo), niobium (Nb), nickel (Ni), platinum (Pt), tantalum (Ta), titanium (Ti), depleted uranium (U), vanadium (V), tungsten (W), yttrium (Y), zirconium (Zr), and/or alloys thereof. The term “alloy” refers to materials where the alloys include at least fifty percent of one of the above base metals. The remainder of such materials may include various combinations of other periodic elements. More specifically, some embodiments of the invention may provide nanostructured versions of the above-referenced metals which have been stabilized by the addition of alkaline earth metals such as barium (Ba), Sr, calcium (Ca), and Mg. In this context, stabilization refers to: the retention of a grain size of less than one micron after having been annealed at homologous temperature representing eighty percent (for example) of the absolute melting point of the respective base metal; and the retention of Vickers hardness representing at least fifty percent of the as-processed hardness after having been annealed at homologous temperature representing eighty percent, for example, of the absolute melting point of the respective base metal. As indicated by thermodynamic principles, nanocrystalline microstructures in metals are subject to coarsening at elevated temperatures. The result of such nano-to-micro scale coarsening is the loss of the remarkable physical properties and deformation behaviors associated with these microstructures. This inherent thermal instability frequently limits the overall processing and applications of nanocrystalline metals. That is, nanocrystalline materials would benefit from thermal stabilization, which, in turn, would aid real world applications. The alloys stabilized by Sr described herein significantly modify the existing structure of non-stabilized nanocrystalline metals and alloys making such materials more thermally stable and mechanically resistant. The Sr stabilized nanocrystalline alloys may be stable after exposure to extremely high temperatures and may be appropriate for many relevant applications. BRIEF DESCRIPTION OF DRAWINGS The novel features of the disclosure are set forth in the appended claims. However, for purposes of explanation, several embodiments are illustrated in the following drawings. FIG. 1 illustrates an example overview of one or more embodiments described herein, in which a nano-structured alloy material is generated; FIG. 2 illustrates a flow chart of an exemplary process that synthesizes a nano-structured alloy material; FIG. 3 illustrates a two-dimensional plot, in which grain size is indicated relative to annealing temperature for iron-based and titanium-based compounds; FIG. 4 illustrates a two-dimensional plot, in which grain size is indicated relative to annealing temperature for aluminum-based compounds; FIG. 5 illustrates a bar chart, in which hardness is indicated relative to annealing temperature for various substances; <figref idrefs="DRAWINGS
Filing details
- Inventors
- Vincent H. Hammond
- Assignee
- U.S. Government, as Represented by the Secretary of Army
- Filed
- Aug 9, 2024
- Granted
- Application pending
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