TZM Alloy Preparation

TZM alloy preparation methods commonly used in melting and powder metallurgy method.

Melting method is pure molybdenum and a certain amount of Ti, Zr and other elements in a vacuum or hydrogen under the protection of melting, and casting or machining using manner TZM bar or blank; the powder with high purity molybdenum powder law and THi2 powder, ZrH2 powder and graphite powder after mixing proportion by cold isostatic pressing, and then sintered at high temperature under protective atmosphere to obtain a blank TZM. Blank then after high-temperature hot (hot forging), high-temperature annealing temperature hot (in temperature forging), medium temperature annealing to eliminate stress, then warm rolling (warm forging) to obtain TZM alloy finished material.

Numerous studies show that molybdenum alloy plastic - brittle transition temperature (DBTT) and the fracture mode and grain size, grain morphology, pore density, organizational structure, alloying elements and the second phase particle distribution and so on. Therefore, the control TZM alloy elements and impurity elements to add quality content on the mechanical properties is essential.

Table 1 carbon arc melting pure molybdenum (LCAC) and TZM molybdenum alloy

Mechanical properties data after forging

Table 2 TZM alloy(Titanium Zirconium Molybdenum) composition of the required range of each element, wherein the oxygen and silicon is to strictly control the impurity element by the body after a burn if the oxygen content is still high, then the sintering will be in the grain boundary pores, thereby reducing the strength of the alloy, the silicon in the alloy mainly grain boundary inclusions adversely affect the performance of the alloy.

Table 2 TZM alloy(Titanium Zirconium Molybdenum) composition%

Extensive literature confirmed that Mo-based alloy to obtain good tensile properties at low temperature, must meet the fine grain size, high and low oxygen content and oxygen conditions. In the TZM alloy system, reported in the literature up to now, and has excellent properties of the alloy composition with Mo-0.5Ti-0.008Zr and Mo-0.5Ti-0.1Zr. These may be prepared by powder metallurgy, can be prepared by melting.

Currently, the U.S. and HCStarck Cleveland prepared by arc melting the adoption of the two alloys, the oxygen content can be controlled at 0.002% or less, Si content is controlled at 10 mg / kg or less.

Powder metallurgy method and the arc melting method is a common method for preparation of TZM alloy, but recently in the literature reported that use of thermite reaction of TZM alloy(Titanium Zirconium Molybdenum) . The method is based on MoO2, TiO2 and ZrO2 as a raw material, Al reducing agent, CaO flux to do, the reaction and add a certain amount of C, and prepared by the reaction of the aluminum alloy hot reaction mass, and then the reactant alloy arc melting furnace in , melting under argon get TZM billets, hot rolled billets after the last 1 000 ℃ annealing 6 h, the resulting TZM alloy. This contrasts with the conventional methods, the raw material used directly oxides, reducing raw material costs, and alloys prepared by this method has high hardness and good workability after hot rolling, while the surface of alloy of Al and Si compound TZM alloy material makes high-temperature oxidation resistance increased. However, a disadvantage of this method is that removal of impurities in the composition and the regulation process is relatively complicated.

In preparing TZM alloy, regardless of preparation method generally required final extrusion, forging or rolling, to improve plasticity and workability. But alloy after extrusion, forging or the residual stress is generated after rolling, and therefore the alloy is annealed. Generally in a vacuum or hydrogen annealing under the protection. TZM alloy as Ti, Zr and C are formed in the alloy carbide precipitation and Ti, Zr solid solution, the recrystallization temperature of the alloy increased. Therefore, TZM alloy annealing temperature is generally above 1 150 ℃, while pure molybdenum metal is generally about 850 ℃.

If you have any interest in our TZM alloy(Titanium Zirconium Molybdenum) or other molybdenum alloy products, please feel free to contact us by email: sales@chinatungsten.com,sales@xiamentungsten.com or by telephone:86 592 512 9696.