What are the factors affecting the sintering of molybdenum alloy TZM alloy bar?

Decomposition and discharge of gas inside the sintered body

Due to the negative pressure in the furnace during vacuum sintering, as soon as the hydride is decomposed, the released hydrogen is immediately pumped out of the furnace by the vacuum pump, and the duration of the gas release is relatively short. During hydrogen sintering, the released gas can only be discharged slowly with hydrogen. In order to avoid the cracking of the molybdenum alloy or the formation of pores, looseness, cracks and other defects during the sintering process, the hydride of Ti and Zr must be decomposed or other adsorbed substances Keep enough time during release to allow gas to be released from the sintered body as much as possible. In this regard, vacuum sintering is more advantageous than hydrogen furnace sintering.

Oxygen content in molybdenum powder

Oxygen in molybdenum powder is a harmful element, and the oxygen content affects the strength and hardness of the molybdenum alloy bar, so the less oxygen in molybdenum powder, the better.

The influence of the protective gas hydrogen

Hydrogen plays a reducing role in the sintering process. The burning loss of carbon in a vacuum atmosphere is less than in a hydrogen atmosphere. The longer the sintering time in the hydrogen furnace, the more serious the burning of carbon and the corresponding decrease in alloy strength of the TZM alloy bars.

Influence of heating rate and temperature

Compared with pure molybdenum, the heating speed of TZM molybdenum alloy should be much slower, and the sintering temperature control is also much stricter. If the sintering temperature is higher than 2100°C, the TZM alloy will spray and melt. If the heating speed is too fast, the molybdenum alloy TZM and TZC will have cracks, holes, looseness, cracks and other defects.