BULLETPROOF LIGHTWEIGHT METAL MATRIX MACROCOMPOSITES WITH CONTROLLED STRUCTURE AND MANUFACTURE THE SAME

摘要

The lightweight bulletproof metal matrix macrocomposites (MMMC) contain (a) 10-99 vol. % of permeable skeleton structure of titanium, titanium aluminide, Ti-based alloys, and/or mixtures thereof infiltrated with low-melting metal selected from Al, Mg, or their alloys, and (b) 1-90 vol. % of ceramic and/or metal inserts positioned within said skeleton, whereby a normal projection area of each of said inserts is equal to or larger than the cross-section area of a bullet or a projectile body. The MMMC are manufactured as flat or solid-shaped, double-layer, or multi-layer articles containing the same inserts or different inserts in each layer, whereby insert projections of each layer cover spaces between inserts of the underlying layer. The infiltrated metal contains 1-70 wt. % of Al and Mg in the balance, optionally, alloyed with Ti, Si, Zr, Nb, V, as well as with 0-3 wt. % of TiB₂, SiC, or Si₃N₄ sub-micron powders, to promote infiltrating and wetting by Al-containing alloys. The manufacture includes (a) forming the permeable metal powder and inserts into the skeleton-structured preform by positioning inserts in the powder followed by loose sintering in vacuum to provide the average porosity of 20-70%, (b) heating and infiltrating the porous preform with molten infiltrating metal for 10-40 min at 450-750° C., (c) hot isostatic pressing of the infiltrated composite, and (d) re-sintering or diffusion annealing. The positioning of the ceramic inserts in Ti-based powder is carried out by using a metal grid aiding the placement of inserts in a predetermined geometric pattern, and said grid becomes the integral part of the macrocomposite material. The technology is suitable for the manufacture of flat or shaped metal matrix macrocomposites having improved ductility and impact energy absorption such as lightweight bulletproof plates and sheets for airplane, helicopter, and automotive applications.