Syntactic metal matrix materials and methods

摘要

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. The deformation working is typically performed at a yield strength that is adjusted by way of selecting a working temperature at which the yield strength is approximately less than the omniaxial crush strength of the included ceramic microballoons. This deformation causes at least work hardening and grain refinement in the matrix metal.

主权项

1. Method of manufacture comprising:
selecting a syntactic metal foam composite that is comprised of a metal matrix and ceramic microballoons, said syntactic metal foam composite being substantially fully dense except for a syntactic porosity that is provided by said ceramic microballoons, said syntactic porosity having a syntactic porosity volume, said ceramic microballoons having an average unconstrained uniaxial crush strength, and an average omniaxial crush strength that is greater than said average unconstrained uniaxial crush strength, said metal matrix having a yield strength at a working temperature, which yield strength is less than said average omniaxial crush strength and more than said uniaxial crush strength; bringing said syntactic metal foam composite to approximately said working temperature; deforming said syntactic metal foam composite to a predetermined shape while continuously constraining said syntactic metal foam composite to a substantially constant volume, said deforming being carried out with a deformation force that is below approximately said average omniaxial crush strength, and at least as great as approximately said yield strength; and recovering a resultant deformed syntactic metal foam composite having a deformed syntactic porosity and substantially no non-syntactic porosity, said deformed syntactic porosity having a volume that is at least about 90 percent or 95 percent of said syntactic porosity volume.