Patent ID: 8138448
Filing Date: 2012-03-20
Classification: B32B,Y10T

Abstract:
1. A method of fabricating negative coefficient of expansion-engineered elements or particles, said method comprising: providing two layers of a sheet material in surface contact with each other, each said layer comprising two superimposed sheets having differing coefficients of thermal expansion forming a bilayer; laser welding said bilayers about an enclosing path so as to produce a closed structure; laser cutting said bilayer sheets in a path extending externally of said laser welded path to separate said closed structure from the remaining bilayer sheets; and imparting a cooling environment to said closed structure whereby said different coefficients of thermal expansion of said bilayers causes said closed structure to expand in volume; wherein each said bilayer is initially formed from superimposed sheets constituted of identical metallic material, each said sheet having the contiguous surfaces thereof oxidized to a half-thickness of the respective sheet subsequent to being laser welded so as to form said closed bilayer structure.