Low thermal stress metal structures
AssigneePowdermet, Inc.
InventorsAndrew J. Sherman, Brian Werry
Life of this patent
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Abstract
A structured three-phase composite which include a metal phase, a ceramic phase, and a gas phase that are arranged to create a composite having low thermal conductivity, having controlled stiffness, and a CTE to reduce thermal stresses in the composite when exposed to cyclic thermal loads. The structured three-phase composite is useful for use in structures such as, but not limited to, heat shields, cryotanks, high speed engine ducts, exhaust-impinged structures, and high speed and reentry aeroshells.
Claims23
A three or more phase composite which includes a ceramic phase, a non-solid phase, and a metal phase that includes niobium, said non-solid phase and said ceramic phase are segregated into isolated pockets forming a discontinuous phase in said composite, said metal phase is continuous phase in said composite, said composite having a compression modulus that is at least 25% less than a compression modulus of said metal forming said metal phase, said composite also having a thermal conductivity that is at least 40% less than a thermal conductivity of said metal that forms said metal phase, said composite having a density that is at least 20% lower than a density of said metal that forms said metal phase.
A composite that includes a ceramic phase, a non-solid phase, and a metal phase;
- said non-solid phase and said ceramic phase are segregated into isolated pockets forming a discontinuous phase in said composite;
- said metal phase is continuous phase in said composite;
- said ceramic phase is formed of one or more materials selected from the group consisting of carbon, SiAlON, Si3N4, SiC, SiOC, SiO2, Al2O3, aluminates, zirconates, aluminosilicates, and ZrO2;
- said metal phase includes niobium, aluminum;
- said non-solid phase formed of a) a vacuum in one or more cavities in said composite, and wherein said one or cavities is located in said metal phase and/or said ceramic phase, and/or b) a low thermal conductivity gas, and wherein said low thermal conductivity gas includes one or more gases selected from the group of air, one or more noble gasses, and nitrogen;
- said ceramic phase constitutes 5-35 vol. % of said composite;
- said non-solid phase constitutes 10-40 vol. % of said composite;
- a plurality of said ceramic phase is formed of ceramic particles that include one or more cavities that are filled with a portion of said non-solid phase;
- said metallic phase forms about 1-20 vol. % of the composite;
- said composite having a compression modulus that is at least 25% less than a compression modulus of said metal forming said metal phase, said composite also having a thermal conductivity that is at least 40% less than a thermal conductivity of said metal that forms said metal phase, said composite having a density that is at least 20% lower than a density of said metal that forms said metal phase.
Dependencies are inferred from the claim text.