United States of America As Represented by the Administrator of Nasa

Joel A Alexa

Stephen J Hales

Donald Laurence Thomsen, Iii

Brian J Jensen

Roberto J Cano

Sankara N Sankaran

Erik S Weiser

Peter L Messick

Harold Dale Claytor

Peter T Lillehei

Stephen W Smith

Robert S Piascik

Edward H Glaessgen

Michael R Horne

Richard Keith Bird

John A Wagner

Terryl A Wallace

Marcia S Domack

Benjamin T Hailer

Methods for making layered materials and layered materials including high atomic number metals and metal alloys adhered to surfaces are provided. Such surfaces may be oxygen or hydroxyl rich surfaces. Certain methods include depositing a tie down layer of a first metal or metal alloy particles onto a first surface of base material and depositing a high atomic number metal or metal alloy layer onto the first surface after depositing the tie down layer, wherein particles comprising the high atomic number metal or metal alloy layer have a higher atomic number than the first metal or metal alloy particles.

Method of coating high atomic number metals onto oxygen or hydroxyl rich surfaces

In some aspects, this disclosure relates to improved Z-grade materials, such as those used for shielding, systems incorporating such materials, and processes for making such Z-grade materials. In some examples, the Z-grade material includes a diffusion zone including mixed metallic alloy material with both a high atomic number material and a lower atomic number material. In certain examples, a process for making Z-grade material includes combining a high atomic number material and a low atomic number material, and bonding the high atomic number material and the low atomic number together using diffusion bonding. The processes may include vacuum pressing material at an elevated temperature, such as a temperature near a softening or melting point of the low atomic number material. In another aspect, systems such as a vault or an electronic enclosure are disclosed, where one or more surfaces of Z-grade material make up part or all of the vault/enclosure.

Atomic number (Z) grade shielding materials and methods of making atomic number (Z) grade shielding

The present invention provides a process for suppressing abnormal grain growth in friction stir welded aluminum alloys by inserting an intermediate annealing treatment ('IAT') after the welding step on the article. The IAT may be followed by a solution heat treatment (SHT) on the article under effectively high solution heat treatment conditions. In at least some embodiments, a deformation step is conducted on the article under effective spin-forming deformation conditions or under effective superplastic deformation conditions. The invention further provides a welded article having suppressed abnormal grain growth, prepared by the process above. Preferably the article is characterized with greater than about 90% reduction in area fraction abnormal grain growth in any friction-stir-welded nugget.

Abnormal grain growth suppression in Al alloys

Aspects relate to methods of building Z-graded radiation shielding and covers. In one aspect, the method includes: providing a substrate surface having about medium Z-grade; plasma spraying a first metal having higher Z-grade than the substrate surface; and infusing a polymer layer to form a laminate. In another aspect, the method includes electro/electroless plating a first metal having higher Z-grade than the substrate surface. In other aspects, the invention provides methods of improving an existing electronics enclosure to build a Z-graded radiation shield by applying a temperature controller to at least part of the enclosure and affixing at least one layer of a first metal having higher Z-grade than the enclosure.

Methods of making Z-shielding

Various embodiments provide methods in which a metal matrix composite (MMC) material is incorporated into a metallic structure during a one-step near-net-shape structural forming process. Various embodiments provide in-situ selective reinforcement processes in which the MMC may be pre-placed on a forming tool in locations that correspond to specific regions in the metallic structure. Various embodiment near-net-shape structural forming processes may then be executed and result in various embodiment metallic structural components with selectively-reinforced regions that provide enhanced mechanical properties in key locations.

In-situ selective reinforcement of near-net-shaped formed structures

Disclosed are methods of building Z-graded radiation shielding and covers. In one aspect. the method includes: providing a substrate surface having about medium Z-grade; plasma spraying a first metal having higher Z-grade than the substrate surface; and infusing a polymer layer to form a laminate. In another aspect, the method includes electro/electroless plating a first metal having higher Z-grade than the substrate surface. In other aspects, the invention provides methods of improving an existing electronics enclosure to build a Z-graded radiation shield by applying a temperature controller to at least part of the enclosure and affixing at least one layer of a first metal having higher Z-grade than the enclosure.

A method of fabricating a composite material includes utilizing a radio frequency plasma process to form a plasma plume comprising nanoparticles. The nanoparticles may comprise boron nitride nanoparticles, silicon carbide nanoparticles, beryllium oxide nanoparticles, or carbon nanoparticles. The nanoparticles may comprise nanotubes or other particles depending on the requirements of a particular application. The nanoparticles are deposited on a substrate by directing a plasma plume towards the substrate. The nanoparticles are formed in the plasma plume immediately prior to being deposited on the substrate. The nanoparticles may form a mechanical bond with the fibers in addition to a chemical bond in the absence of a catalyst. The substrate may comprise a fiber fabric that may optionally be coated with a thin layer of metal. Alternatively, the substrate may comprise a solid material such as a metal sheet or plate.

Nanoparticle hybrid composites by RF plasma spray deposition

A composite material includes a structural material and a shape-memory alloy embedded in the structural material. The shape-memory alloy changes crystallographic phase from austenite to martensite in response to a predefined critical macroscopic average strain of the composite material. In a second embodiment, the composite material includes a plurality of particles of a ferromagnetic shape-memory alloy embedded in the structural material. The ferromagnetic shape-memory alloy changes crystallographic phase from austenite to martensite and changes magnetic phase in response to the predefined critical macroscopic average strain of the composite material. A method of forming a composite material for sensing the predefined critical macroscopic average strain includes providing the shape-memory alloy having an austenite crystallographic phase, changing a size and shape of the shape-memory alloy to thereby form a plurality of particles, and combining the structural material and the particles at a temperature of from about 100-700&#xb0; C. to form the composite material.

Strain-detecting composite materials

Abnormal grain growth suppression in aluminum alloys

Methods of building Z-graded radiation shielding and covers. In one aspect, the method includes: providing a substrate surface having about medium Z-grade; plasma spraying a first metal having higher Z-grade than the substrate surface; and infusing a polymer layer to form a laminate. In another aspect, the method includes electro/electroless plating a first metal having higher Z-grade than the substrate surface. In other aspects, the methods include improving an existing electronics enclosure to build a Z-graded radiation shield by applying a temperature controller to at least part of the enclosure and affixing at least one layer of a first metal having higher Z-grade from the enclosure.

A metal/fiber laminate has a plurality of adjacent layers. Each layer is porous and includes an arrangement of fibers. At least one of the layers has its fibers coated with a metal. A polymer matrix permeates each such arrangement.

Growing community of inventors

Hampton, VA, United States of America

Joel A Alexa