Materials

Coating alumina fibers with sputtered metal has been proposed as a means to enable the fibers to retain more strength when the fibers are incorporated into metal-matrix composites. If the alumina fibers could be made to retain more strength, then it would be possible to manufacture such...

A report presents updated information on the developments described in "MoSi2-Based Composite Materials for Aircraft Engines" (LEW-16617),NASA Tech Briefs, Vol. 22, No. 9 (September 1998), page 62. To recapitulate: Hybrid composites of (1) SiC-based fibers within (2) matrices that...

Probabilistic Ceramic Matrix Composite Analyzer (PCEMCAN) is a user-friendly computer program that predicts uncertainties in the mechanical and thermal properties of ceramic-matrix composite (CMC) materials. These materials are candidates for fabrication of structural components that will be...

The figure shows a prototype of a magnetostrictively actuated mechanism that would rotate an optical filter wheel for a high-performance infrared camera or telescope. Typically, a high-performance infrared instrument and its filter wheel are operated inside a cryogenic system. In conventional practice, the...

A process that is undergoing development would be used to mass-produce textured polycrystalline rods of a terbium/dysprosium alloy for cryogenic magnetostrictive actuators. The rolling-and-heat-treatment process described in the preceding article yields a high degree of crystal orientation, but is...

The differential miscibility of castor oil in ethanol and water would be exploited to separate ethanol from water, according to a proposal. Burning the separated ethanol would produce more energy than would be consumed in the separation process. In contrast, the separation of a small amount...

The differential solubility of sulfur in ethanol and water could be exploited to separate ethanol from water. The energy that could be produced by burning the separated ethanol would be more than that required in the separation process. In contrast, the separation of a small amount of...

Hybrid versions of the high-performance overwraps used on some low-pressure tanks have been proposed. The hybrid overwraps would weigh less than do the corresponding nonhybrid overwraps, as explained below.

Pressure vessels overwrapped with graphite-fiber-based composite materials that become damaged would be salvaged by a proposed repair technique. The need for the technique arises as follows: High-performance graphite-fiber-based composites are very susceptible to damage from impact or cutting....

A report describes an experimental study of the surface-chemical, microstructural, and tribological properties of cubic boron nitride (c-BN) films, which are potentially useful as hard, wear-resistant coatings on bearings and on steel-cutting tools. For the experiments, BN films about 500 nm thick were...

Damage-tolerant polymeric composite overwraps have been proposed for lightweight pressure vessels that are made of composites of graphite fibers in polymeric matrices. Graphite-fiber/polymer composites are vulnerable to impact damage; overwraps on the pressure vessels...