tzm powder is a molybdenum alloy with 0.50% titanium, 0.08% zirconium and 0.02% carbon. It has higher recrystallization temperature and better weldability than pure molybdenum.
Besides its high melting point, TZM has excellent properties of strength, elastic modulus, small linear expansion coefficient, low vapor pressure and good electrical and thermal conductivity. It is suitable for various applications, such as high-temperature furnace components, nozzle throat linings, rotating anodes in X-ray tubes, etc.
The most common preparation method is arc melting-casting and powder metallurgy. In addition, TZM is processed by laser powder-bed fusion (LPBF).
Processing TZM by LPBF can produce crack-free samples with a density of 99.7%, which is a major advance in the development of TZM. During the fusion process, the MoO2 impurities segregate to grain boundaries and form a ternary molybdenum-titanium carbide.
These impurities weaken grain boundaries and cause TZM to have hot cracking problems. However, when TZM is processed by LPBF, the ternary molybdenum-titanium-zirconium carbide can suppress the segregation of oxygen to grain boundaries and prevent cracking at a high density.
The result is that TZM is more resistant to hot cracking than pressed and sintered molybdenum.
TZM also exhibits strong resistance to corrosion and oxidation, which makes it ideal for use in the vacuum furnace industry. It is the material of choice for load-bearing hearths and horizontal posts in vacuum furnaces because it has twice the strength and can withstand temperatures above 1300 degrees Celsius.
TZM is also the material of choice for load-bearing cathodes, grids and high-voltage rectifier components in electric power stations because it is less prone to delamination or fracture under repeated temperature cycling. It is also the material of choice for a variety of X-ray tubes, because it is less prone to recrystallization or embrittlement than pure molybdenum.