US Patent 10323919 Frangible, ceramic-metal composite objects and methods of making the same

In making frangible objects, including lead-free bullets and other projectiles, powdered metal primary and powdered ceramic secondary phases are mixed and densified at an elevated temperature such that the ceramic phase forms a brittle network. Different combinations of metal and ceramic phases may be used to achieve desired chemical and physical properties. Any appropriate mixing, forming, and/or thermal processing methods and equipment may be used. Degrees of frangibility, strength, and toughness can be adjusted to suit a given application by precursor selection, degree of mixing, relative amounts of metal and ceramic phases, forming method, and thermal and mechanical processing parameters.