Abstract: A rhenium alloy is provided having from about 50 atomic % to 99 atomic % rhenium and a refractory compound particulates that are present in the alloy in an amount up to about 10 atomic %. The refractory compound comprises a nano-scale dispersion that is incorporated into the conventional rhenium structure. The nano-scale dispersion acts as grain boundary pins that result in a relatively fine grained, equiaxed structure that improves the mechanical properties of the alloy and helps to minimize the growth of large grains during operations at high temperatures. As a result, the amount of the rhenium used in high temperature applications may be reduced without sacrificing its high temperature and mechanical properties. Cryomilling in the presence of nitrogen may be used to prepare the rhenium alloy having a stable fine grain structure at high temperatures.

Abstract: An aluminum or aluminum-alloy material sheet comprised of an aluminum material having an ultra-fine, submicron grain structure. The strength and physical properties of the aluminum or aluminum-alloy material sheet are improved over previous aluminum and aluminum-alloy material sheets because the aluminum is produced by cryomilling the aluminum or aluminum-alloy materials into a metal powder with ultra-fine, submicron grain structure. The powder is consolidated and rolled into the form of a sheet.

Abstract: Systems and methods are disclosed to effectively fracture dendrite arms and/or reduce grain size in a solidifying metal melt pool. Ultrasonic energy is applied to the solidifying metal in the liquid metal pool directly or via a substrate on which the metal is provided. In another embodiment, ultrasonic energy is applied over a range of frequencies and/or tuned to the resonant frequency of solidifying dendrite arms. Advantageously, the present invention prevents or hinders the growth of large columnar dendrites and instead allows for the formation of a high density of randomly oriented grains with a reduction in grain size, thereby enhancing the quality of the deposited metal and therefore improving the mechanical properties of the fabricated or repaired structure.

Abstract: A lightweight rocket engine combustion chamber and an associated method are provided. In one embodiment of the present invention, the combustion chamber includes an inner liner defining an inlet and an outlet, and at least one bonding strip attached to the liner. The combustion chamber also includes a structural jacket bonded to the bonding strip.

Abstract: Nanostructure aluminum fiber-metal laminates are disclosed. In one embodiment, a laminate includes a nanostructure aluminum metal layer bonded to a fiber layer. In another embodiment, the nanostructure aluminum metal layer may be produced by mechanically alloying an aluminum alloy powder submerged in a liquid nitrogen solution. Alternately, a plurality of fiber layers may be disposed between a pair of nanostructure metallic layers. The laminate may be cured at optimal temperatures that do not affect the properties of the composite. In another embodiment, a hollow core may be incorporated between structure aluminum fiber-metal laminate assemblies.

Abstract: A method of direct metal fabrication to form a metal part which has a relative density of at least 96%. There is provided a powder blend which comprises a parent metal alloy, a powdered lower-melting-temperature alloy that comprises greater than 10% of total weight of the powder blend, and an organic polymer component (a thermoplastic polymer and a thermosetting polymer) that comprises less than 3% by weight of a total weight of the powdered blend. There is a laser-build powder processing operation (a selective laser sintering (SLS) operation) to fabricate a green body. The green body is then placed in a furnace and the temperature raised to sufficiently high temperature to perform a supersolidus liquid phase sintering operation to form the metal part.

Abstract: Methods and powder blends are provided for fabricating a metal part. One method includes the first steps of spreading a layer of a powder blend on a platform, the powder blend including a titanium base metal or alloy, and an alloying metal having a lower melting temperature than that of the base metal or alloy. Next, an energy beam is directed onto selected areas of the powder blend layer to thereby melt the alloying metal. Then, the alloying metal is re-solidified by withdrawing the energy beam from the powder blend layer. Then, a preform part is built up by iteratively performing the spreading, melting, and re-solidifying steps on additional adjacently formed layers. A metal liquid phase sintering process is performed at a temperature sufficient to melt the alloying metal but not the base metal or alloy.