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.

A syntactic metal foam composite that is substantially fully dense except for syntactic porosity is formed from a mixture of ceramic microballoons and matrix forming metal. The ceramic microballoons have a uniaxial crush strength and a much higher omniaxial crush strength. The mixture is continuously constrained while it is consolidated. The constraining force is less than the omniaxial crush strength. The substantially fully dense syntactic metal foam composite is then constrained and deformation worked at a substantially constant volume. This deformation causes at least work hardening and grain refinement in the matrix metal. The resulting deformed syntactic metal foam composite has an energy absorption capacity that is at least 1.5 to 2 or 3 times or more the energy absorption capacity of the precursor substantially fully dense syntactic metal foam composite.

A method of making a porous metal matrix composite is provided. The method includes mixing a metal powder, a plurality of inorganic particles, and a plurality of discontinuous fibers to form a mixture, wherein the metal powder comprises aluminum, magnesium, an aluminum alloy, or a magnesium alloy. The method further includes sintering the mixture to form the porous metal matrix composite. Typically, the inorganic particles comprise porous particles or ceramic bubbles or glass bubbles, and the inorganic particles and the discontinuous fibers are dispersed in the metal. The metal matrix composite has a lower density than the metal and an acceptable yield strength.

A method is presented for producing hollow microspheres of metal oxides (HMOMS) and/or hollow metal silicates microspheres (HMSMS) in a transforming solution. The transforming solution contains an atom M, or an M-ion, or a radical containing M. M in the transforming solution has the thermodynamic ability to replace silicon atoms in hollow silica microspheres (HSMS) and/or hollow glass microspheres (HGMS). The maximum temperature for transformation is set by the chemical physical properties of the transforming solution, and the viscosity of the silica in the walls of the HSMS and/or the glass in the walls of the HGMS. Viscosity, of enough magnitude, helps retain the desired shape of the hollow sphere as it is transformed to HMOMS and/or HMSMS. Non-spherical shapes can be produced by increasing the transformation temperature whereby the viscosity of the walls of the HSMS and/or the HGMS is reduced. Transformation can take place at a single temperature or at several temperatures, each temperature for a separate hold time.

Methods are presented for: 1. production of micro composite castings and continuous production of sheets of micro composites, both consisting of hollow spheres in a matrix, 2. harvesting of HMOMS and HMSMS, and 3. specialty castings for anisotropic properties using 3-dimensional printing

A powder-metallurgical body and a method for producing such a body. The powder-metallurgical body is formed with a seating base for seating a sealing element to produce a seal with respect to fluids, such as liquids and/or gases. The body is redensified in a low-lying depth region of the seating base.

In one aspect, additive manufacture techniques are described herein which enable the selective location of one or more density gradients within printed articles. Methods described herein can permit high density and high quality printed regions to be located at one or more selected areas of the printed article. The high density/high quality printed regions, for example, can be located at functional areas of the printed article, such as areas of high wear and/or stress.