The ingots of niobium tungsten alloy are usually prepared by powder metallurgy and smelting. Powder metallurgy is the preparation of ingots by mixing, pressing and sintering niobium, tungsten and other elements powder into pre-alloy strips, and then using more than two times of vacuum electron beam smelting or vacuum arc smelting or the combination of the two smelting methods. The purpose of electron beam smelting is to remove impurities (such as interstitial elements, low melting point metals and nonmetallic impurities) in prealloy strip, control alloy composition and prepare ingots of a certain size. The purpose of vacuum arc smelting is to prepare billets with more uniform composition, finer grain and larger diameter. After the billet is cut, the billet is extruded and forged at the temperature above 1200℃, and then rolled and drawn at the temperature below 500℃, bar, plate, strip, wire and other products can be prepared.
The tungsten niobium alloy is generally welded by inert gas tungsten electrode welding and electron beam welding, and it can also be brazed with titanium and titanium alloy. Before welding, the welding metal must be used CCl4 and other organic solvents to remove oil and other stains, welding operation must be in a high vacuum (vacuum degree less than 1. 333×10Pa) or high purity inert gas protection box. Niobium tungsten alloy welding operation must be very careful, otherwise it is not easy to get good plastic joints.
Niobium tungsten alloy has high strength at high temperature and good plasticity at room temperature. It is mainly used in shuttle skinning, nuclear reactor engineering, jet engine parts and space power generation system heat radiation screen and duct.
