Titanium zirconium molybdenum alloy
TZM (Titanium-zirconium-molybdenum alloy), is a superalloy, a solid solution hardened and particle reinforced molybdenum base alloy. Therefore, TZM (titanium zirconium molybdenum alloy) provides better weldability. TZM (Titanium-zirconium-molybdenum alloy) is 0.50% titanium, zirconium and 0.08%, and the remaining 0.02% carbon molybdenum alloy. TZM (titanium-zirconium-molybdenum alloy) has higher recrystallization temperature, higher strength, hardness than non-alloy molybdenum at room temperature and high temperature and good ductility. In addition, TZM (titanium zirconium molybdenum alloy) has good thermal conductivity, low vapor pressure, good corrosion resistance, so it can be machined.
TZM (titanium-zirconium-molybdenum alloy) and other molybdenum alloys have higher recrystallization temperatures, higher heat resistance and better creep resistance than pure molybdenum. At present, TZM (Mo-0.5%Ti-0.008%Zr) and TZC (Mo-1.25%Ti-0.15%Zr-0.15% carbon) are the most widely used. Good high temperature strength and high recrystallization temperature, and good room temperature plasticity. Made by powder metallurgy and vacuum arc melting method. It can be used as high temperature structural material and tool material for high temperature machining under extremely harsh conditions. For example, die casting molds and cores for aluminum and copper alloys, cast iron and iron alloys, hot extrusion tools for stainless steel, and hot processing tips for seamless steel tubes. It can also be used as parts of space rocket device and flight surface. Using hafnium instead of titanium, molybdenum alloy is strengthened by the method of forming duplex structure.
Structural element of furnace, used for casting aluminum alloy, hot stamping die insertion. Rocket nozzles and electrodes. Molybdenum alloy with a small amount of titanium, zirconium and trace carbon has high high temperature strength and is the most widely used molybdenum alloy at present. The nominal composition of molybdenum-titanium-zirconium alloy is Mo-0.5Ti-0.08Zr, and the general grade is TZM. In 1956, Clay Max Molybdenum Company produced the first industrial scale TZM alloy ingot. In the late 1950s, TZM alloy materials can be produced in large quantities by casting method. By the 1970s, the alloy was the best general purpose molybdenum alloy. In the mid-1960s, China began to study the production of TZM alloy by casting method. In the 1970s, large-scale trial production was carried out and TZM alloy products were produced by casting method and powder metallurgy method.
TZM alloy chemical composition (%) in order to meet the use of higher temperature and strength requirements, on the basis of TZM alloy to increase titanium, zirconium, carbon elements and the formation of molybdenum titanium zirconium carbon alloy, its general composition is Mo-1.25Ti-0.15Zr-0.15C, known as TZC alloy. However, because of its difficult deformation, so in the 1990s, it has not yet formed an industrial production scale, no series of products, only according to the requirements of the use of products.
Strengthening mechanism The strengthening mechanism of TZM alloy and Tzc alloy is introduced respectively. The strengthening mechanism of TZM alloy is as follows :(1) cold working deformation hardening not only improves the strength of the alloy and refines the grain size, but also produces a ductile fibrous microstructure. (2) A small amount of titanium and zirconium elements are dissolved in the molybdenum matrix to increase the structure stability and increase the recrystallization temperature. (3) The dispersion strengthening caused by the precipitation of spherical compound carbide particles formed by the interaction of replacement elements (titanium, zirconium) and gap elements (carbon) in molybdenum matrix improves the high temperature strength and creep resistance of molybdenum. The content of carbon and titanium in TZM alloy has the same critical proportion as that in Mo-0.5Ti alloy. Powder metallurgy method.
