TiAl合金反重力铸造用陶瓷型壳的调整

Modification of Ceramic Mould for Counter-gravity Casting of TiAl Alloy

在真空反重力铸造过程中,熔融的TiAl合金是通过两真空腔体的压力差压入陶瓷型壳中的。因此,真空反重力铸造过程中型壳必须具有良好的透气性和必要的强度。实验表明,在料浆中加入少量糊精可以明显增加型壳的透气性,在型壳制作的过程中通过加入纤维可增强其强度。利用这种型壳,通过反重力低压真空铸造出的TiAl增压器涡轮的叶片尖端厚度可薄至0.5mm。

In the process of counter-gravity casting,the molten TiAl is pushed forwards ceramic shell through the pressure difference between the two vacuum chambers, so the ceramic shell mould should possess enough air permeability and good strength. The experiment indicates that the mould＇s permeability can be obviously increased by adding small amount of dextrin to the slurry; using fibre in the ceramic mould preparation process can reinforce the shell mould＇s intensity. Applying the shell mould with dextrin and fibre, the TiAI turbochargers blade tips produced by counter-gravity casting is only 0.5 mm