Zirconium alloy

A nonferrous alloy in which zirconium is the base and other elements are added. The main alloy elements are tin, niobium, iron and so on. Zirconium alloy has good corrosion resistance, moderate mechanical properties and low atomic thermal neutron absorption cross section in 300 ~ 400℃ high temperature and high pressure water and steam. It has good compatibility to nuclear fuel and is often used as the core structural material of water-cooled nuclear reactors. In addition, zirconium has excellent corrosion resistance to a variety of acids, bases and salts, and has a strong affinity with oxygen, nitrogen and other gases. Therefore, zirconium alloy is also used in the manufacture of corrosion resistant parts and pharmaceutical mechanical parts, and is widely used as a non-evapotranspiration degasser in the electric vacuum and bulb industries.

There are two kinds of zirconium alloys produced on industrial scale: zirconium tin series and zirconium niobium series. The grades of the former alloy are Zr-2 and Zr-4, and the typical representative of the latter is Zr-2.5Nb. In zirconium-tin alloys, alloying elements such as tin, iron, chromium and nickel can improve the material's strength, corrosion resistance and thermal conductivity of corrosion resistant film, and reduce the sensitivity of surface state to corrosion. Zr-2 alloys are usually used in boiling water reactors and Zr-4 alloys in pressurized water reactors. In zirconium and niobium alloys, the corrosion resistance of the alloys is the best when the addition of niobium reaches the solution limit of zirconium crystal structure at service temperature. Zirconium alloy has isomorphic transformation, and its crystal structure is body-centered cubic at high temperature and densely arranged hexagonal at low temperature. Zirconium alloy has good plasticity and can be made into tubes, plates, bars and wires by plastic processing. Its weldability is good, can be used for welding processing.