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What Do You Know About the Disadvantages of TZM Plate or Sheet?

TZM alloy is an attractive molybdenum-based alloy (0.4-0.54% Ti, 0.06-0.12 %Zr, 0.01-0.04% C, balance Mo) utilized in industries with high strength, high temperature and vacuum requirements, including aerospace, electronics and heat treatment. TZM alloy plate can perfectly server these areas when the working temperature ranges from 700 ℃ to 1400 ℃。

Compared with pure molybdenum plate, TZM plate has a more stable crystal structure and a higher recrystallization temperature. This is due to the small amount of zirconium and titanium doped in the molybdenum substrate. In addition, the extremely fine-sized composite carbides Mo2C, TiC and ZrC refine and suppress the molybdenum grains, so that alloy plate has better weldability and creep resistance than the pure molybdenum plate.

However, there are still many disadvantages for this material. 

1. Oxidation. Although the material can be used in the temperature above 2000℃,the premise is that its working environment is vacuumed or under the protection of nitrogen, cracked ammonia or other atmosphere. Molybdenum alloy plates will start to oxide at about 400 ℃ and become to fast at about 700 ℃. If they work at above 2000 ℃, they will oxide immediately. 

2, Welding. Molybdenum or tungsten products can be welded, but require certain equipment and technology. Normally, the technology includes cooling welding and vacuum welding with pointed welding wire. Silver, stainless steel or structural alloy steel can not be the material of wire. It must be with very high melting point and strength, such as TZM. 

3, Form. The form of TZM alloy products is limited as they can not be bent even with small angles. If a product requires to be bent into certain shapes, it should be through riveting or welding together two parts. 

Apart with plates, TZM mill products available from either process include forging billets, bar, rod, sheet and foil. All forms in basically the same size range as pure molybdenum with the exception of thin foil. 

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