摘要:
以钛白粉为原料, 采用电铝热还原的方法一步合成制备TiAl合金。研究了不同温度和不同配铝量对渣—金分离, 渣系的物相, 合金组织、成分和物相的影响规律。通过理论分析可以看出, 焙烧温度提高, 渣的黏度降低, 有利于实现渣金分离, 从试验研究可以看出, 温度为1 550℃时渣金分离效果较好;配铝量对还原渣和合金的成分有较大影响, 配铝量不足, 渣中有较多的低价钛氧化物存在, 导致渣的熔点升高和黏度增大, Al/TiO2>0.7时, 渣—金分离较好;配铝量增加提高了合金收率及钛收率, 且使钛铝合金中铝含量增加及物相发生转变, Al/TiO2=0.7, 合金中的主要物相TiAl和Ti3Al, Al/TiO2=0.9时, 主要物相为TiAl和TiAl3。通过XRD、SEM和能谱分析可以看出, 合金中夹杂的渣的主要物相为CaAl4O7。
Abstract:
Ti-Al alloy was prepared using electric aluminothermic reduction method with titanium white as raw materials.The influence of temperature and aluminum addition on the alloy-slag separation,phase of slag,microstructure,composition and phase of alloy were researched.Through theoretical analysis it shows that the elevated roasting temperature can lower the viscosity of slag in favor of the alloy-slag separation.A better separation of alloy and slag can be obtained at 1 550 ℃ according to the experiments.Addition amount of aluminium has significant influence on the compositions of alloy and slag.The melting point and viscosity of slag increase with presence of massive low-valence titanium oxides in the slag caused by insufficient aluminium addition,and the slag-alloy separation is favorable with Al/TiO2＞0.7.Increasing the aluminum addition can enhance the yield rate of alloy and titanium.Meanwhile,the aluminium content in Ti-Al alloy increases and the alloy phases convert.The main phases of alloy are TiAl and Ti3Al as Al/TiO2= 0.7 while TiAl and TiAl3 as Al/TiO2= 0.9.SEM,XRD and EDS analysis show that the slag included in alloy exists as CaAl4O7.
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