10,902 research outputs found
Materials for advanced rocket engine turbopump turbine blades
A study program was conducted to identify those materials that will provide the greatest benefits as turbine blades for advanced liquid propellant rocket engine turbines and to prepare technology plans for the development of those materials for use in the 1990 through 1995 period. The candidate materials were selected from six classes of materials: single-crystal (SC) superalloys, oxide dispersion-strengthened (ODS) superalloys, rapid solidification processed (RSP) superalloys, directionally solidified eutectic (DSE) superalloys, fiber-reinforced superalloy (FRS) composites, and ceramics. Properties of materials from the six classes were compiled and evaluated and property improvements were projected approximately 5 years into the future for advanced versions of materials in each of the six classes
Theory of amorphous ices
We derive a phase diagram for amorphous solids and liquid supercooled water
and explain why the amorphous solids of water exist in several different forms.
Application of large-deviation theory allows us to prepare such phases in
computer simulations. Along with nonequilibrium transitions between the ergodic
liquid and two distinct amorphous solids, we establish coexistence between
these two amorphous solids. The phase diagram we predict includes a
nonequilibrium triple point where two amorphous phases and the liquid coexist.
While the amorphous solids are long-lived and slowly-aging glasses, their
melting can lead quickly to the formation of crystalline ice. Further, melting
of the higher density amorphous solid at low pressures takes place in steps,
transitioning to the lower density glass before accessing a nonequilibrium
liquid from which ice coarsens.Comment: revision following review comment
Low-temperature embrittlement of Ti-6Al-4V and Inconel-718 by high pressure hydrogen
Notched specimens of titanium alloy and Inconel-718 exhibit little reduction of notch strength at certain low temperatures under 2000 lb/sq in. hydrogen, unnotched specimens are not embrittled at these temperatures. The degree of Inconel-718 embrittlement is lower than earlier observations under 1000 lb/sq in. hydrogen
Line cutter Patent
Piston in bore cutter for severing parachute control lines and sealing cable hole to prevent water leakage into loa
Effects of hydrogen on ELI titanium alloy Ti-5Al-2.5Sn
Tensile tests on titanium alloy, following abrasion under hydrogen and temperature cycling, reveal lowered tensile strength, increased ductility, and no embrittlement. Fretting the metal on itself in flowing hydrogen or abrading with an iron file in flowing hydrogen produces titanium hydride
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