Materials

Army Explores 3-D Printing's Future Applications

A soldier heads back to camp, grabs a power bar and unloads his gear. The power bar, which was "printed" minutes earlier, contains all the nutrients his body currently needs, according to sensors that are embedded in his uniform. While this may sound like a scene from a sci-fi movie, engineers and scientists at the Army Research, Development and Engineering Command (RDECOM) are looking at ways to use additive manufacturing (aka 3-D printing) to make it a reality.

Posted in: Articles, News, Defense, Manufacturing & Prototyping, Rapid Prototyping & Tooling, Composites, Materials, Metals, Plastics
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Advances in Lightweight Electronics Protection

Lightweighting continues to be a key topic for the aerospace, avionics and defense industries as new metals and composites are being integrated into end products and assemblies with the goal of decreasing overall system weight. As technologies continue to evolve, with components often decreasing in size and increasing in complexity, the materials used to manufacture and protect the latest components and systems are also improving. Whether used in commercial or military aircraft, rockets, satellites, terrestrial or water vessels, or the latest in unmanned air, land and sea vehicles; systems within these industries must meet similar requirements – assemblies, components and electronics must be both lightweight and designed to withstand harsh operating conditions.

Posted in: Articles, Aerospace, Defense, Electronics, Coatings & Adhesives, Avionics, Electronic equipment, Lightweight materials, Lightweighting, Military vehicles and equipment
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Epitaxial Growth of Rhenium with Sputtering

Epitaxial superconducting films of refractory metals are a promising new template for single crystal tunnel barriers in Josephson junction quantum bit (qubit) devices. In existing Josephson junction qubits, it is believed that the widely-used amorphous AlOx tunnel barriers have undesirable two-state fluctuators. It is speculated that single-crystal tunnel barriers such as sapphire (α-Al2O3) may be free of such decoherence sources.

Posted in: Briefs, Aerospace, Defense, Materials, Computer software / hardware, Conductivity, Metals, Refractory materials
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Processing and Characterization of Polycrystalline YAG (Yttrium Aluminum Garnet) Core-Clad Fibers

YAG-based fiber lasers could offer efficient operation at power levels beyond those achievable in current state-of-the-art silica-based fiber lasers if losses can be minimized. To address this, researchers have investigated creating both single-crystal and polycrystalline YAG fibers. Among the cases reported is the preparation of single-crystal YAG fibers using laser heated pedestal growth (LHPG), which resulted in fiber diameters of 400 μm and optical losses around 1–2 dB/m in the 1–3 μm wavelength range. Single-crystal YAG fibers with diameters of ~ 30 μm have even been reported.

Posted in: Briefs, Aerospace, Defense, Materials, Finite element analysis, Fiber optics, Lasers, Materials identification
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Multi-Scale Analysis of Deformation and Failure in Polycrystalline Titanium Alloys Under High Strain Rates

Extensive use of titanium alloys in critical industrial and military applications, such as compressor blades of jet engines and armor of ground combat vehicles, has motivated researchers to understand, measure and tailor the mechanical properties of these alloys over a wide range of strain rates and temperatures. Of special interest has been the mechanical response of these alloys under high rates of deformation and failure under cyclic/dwell fatigue.

Posted in: Briefs, Aerospace, Defense, Materials, Aircraft structures, Body panels, Failure modes and effects analysis, Materials properties, Titanium alloys, Military vehicles and equipment
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Abrasion Testing of Products Containing Nanomaterials

This SOP describes how to detect and quantify the release of nanoparticles from surface coatings into the air using a mechanical process that employs abrasion to simulate sanding. A material containing nanoparticles will be physically abraded and the materials released will be collected in a custom abrasion testing system. They will then be characterized by different methods such as Scanning Electron Microscopy (SEM) or Transmission Electron Microscopy (TEM) and other methods.

Posted in: Briefs, Aerospace, Defense, Materials, Microscopy, Nanomaterials, Wear, Test procedures
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Spectrum Fatigue of 7075-T651 Aluminum Alloy Under Overloading and Underloading

Most structural members and machine components are subjected in service to cyclic loadings of varying amplitude. The variation in stress level follows either a regular or random pattern. The resulting crack growth is affected by the applied load sequence in the early stage (crack initiation) and in the later stage (crack propagation) of fatigue. The fatigue crack growth is known to be retarded by tensile overloads and accelerated by compressive overloads (underloads). However, the phenomenon and mechanism of the load sequence effects, especially those of overloading and underloading, on fatigue crack growth in different environments remain to be clarified.

Posted in: Briefs, Aerospace, Defense, Materials, Failure modes and effects analysis, Aluminum alloys, Fatigue
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New Ice-Repellant Material Could Improve Aviation Safety

Icy conditions can be deadly when flying into bad weather. Researchers at the University of Houston have discovered a material that can be applied to any surface to repel ice. The material, known as a magnetic slippery surface (MAGSS), could be applied to aircraft wings.

Posted in: News, Aerospace, Defense, Coatings & Adhesives, Materials
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‘Nano-Kebab’ Fabric Breaks Down Chemical Warfare Agents

Researchers have created a fabric material containing nanoscale fibers that are capable of degrading chemical warfare agents (CWAs). Uniform coatings of metal-organic frameworks (MOFs) were synthesized on top of the nanofibers, forming unique kebab-like structures. These MOFs are what break down the CWAs, rendering them harmless.

Posted in: News, Defense, Coatings & Adhesives, Composites, Materials
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Composites Self-Heal at Very Low Temperatures

Scientists developed a method of allowing materials, commonly used in aircraft, to self-heal cracks at temperatures well below freezing. A healing efficiency of more than 100% at temperatures of -60 °C was obtained in a glass fiber-reinforced laminate, but the technique could be applied across a majority of self-healing composites.

Posted in: News, Defense, Composites, Materials
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