Materials

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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Army Scientists Synthesize High-Performing Energetic Material

Scientists at the U.S. Army Research Laboratory recently synthesized a new material called bis-isoxazole tetranitrate, or BITN, with potential applications in propulsion and lethality.

Posted in: News, Aerospace, Defense, Materials, Propulsion
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Managing the Impact of Nanomaterials in Aerospace Manufacturing

As the aerospace industry continues to make improvements to safety, comfort and affordability of aircraft, nanomaterials are making their way into more elements of aircraft structure, electronics, glass, textiles and other components. While these materials provide tangible advantages in terms of weight, strength, speed and comfort, their effect on the humans that come into contact with them is still being studied and debated.

Posted in: Articles, Aerospace, Composites, Aircraft structures, Human factors, Materials properties, Nanomaterials
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Turbine Flow Meters: Technology-of-Choice for Measuring Critical Fluid Flow Applications

The aerospace industry has some of the most difficult operating conditions imaginable. Sensors of all kinds used in this industry must stand up to the environment and be able to perform under harsh conditions, fit in extremely tight spaces, and have electronics that can compensate for variable conditions in order to provide precise, repeatable results.

Posted in: Articles, Aerospace, Manufacturing & Prototyping, Materials, Computational fluid dynamics, Downsizing, Sensors and actuators
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