Abstract: A method for reaction forming refractory metal carbides. The method involves the fabrication of a glassy carbon preform by casting an organic, resin-based liquid mixture into a mold and subsequently heat treating it in two steps, which cures and pyrolizes the resin resulting in a porous carbon preform. By varying the amounts of the constituents in the organic, resin-based liquid mixture, control over the density of the carbon preform is obtained. Control of the density and microstructure of the carbon preform allows for determination of the microstructure and properties of the refractory metal carbide material produced. The glassy carbon preform is placed on a bed of refractory metal or refractory metal—silicon alloy. The pieces are heated above the melting point of the metal or alloy. The molten metal wicks inside the porous carbon preform and reacts, forming the refractory metal carbide or refractory metal carbide plus a minor secondary phase.

Abstract: A process for joining solid compositions, comprising placing a first solid composition having a first joining zone and a second solid composition having a second joining zone in a chamber; positioning a first gas phase, which comprises a substance that decomposes to a material that adheres to the first and second solid compositions during the process, proximate the target area; directing an energy beam to the first and second joining zones to selectively deposit material from the first gas phase on the first joining zone and the second joining zone until a joint is formed between the first and second solid compositions wherein the joint adheres to the first and second compositions at the first and second joining zones.