利用等离子发射光谱仪、能谱仪、X射线衍射以及金相分析等手段 ,研究了RE和Al5TiB对消失模铸造B3 19铝合金组织的影响。研究表明 ,在消失模铸造条件下 ,RE的质量分数为 0 .2 %时可使B3 19铝合金的硅相得到较好的变质 ,组织中存在珊瑚状的Al2 Cu相和文字状的α Fe相及针状的 β Fe相 ,且Si相和针状 β Fe相可以作为Al2 Cu的形核基底。但当w(RE) =0 .3 %时 ,会出现富稀土的金属间化合物La3 Al8Si2 。RE还会与Ti发生相互作用形成块状稀土化合物 ,而对组织产生不利影响。研究结果表明 ,在采用RE变质的情况下 ,不宜用Al5TiB中间合金作为细化剂。
Influence of MM and Al5TiB on the microstructure of B319 aluminum alloy in lost foam casting(LFC) was investigated by means of ICP spectroscopy, energy dispersive x ray analysis (EDX), X ray diffraction and microscope analysis. The results showed that Si phase in B319 aluminum alloy could be modified well with 0.2% RE in lost foam casting and coral like Al 2Cu phase, Chinese character α Fe phase and acicular β Fe phase were found also in the structure, of which both Si phase and acicular β Fe can be acted as the substrate for Al 2Cu phase nucleation.Intermetallic compound rich in La La 2Si 2Al 3 would appear with over 0.3% MM addition. MM may react with Ti to form blocky compound containing RE to deteriorate the structures of the alloy. The results showed that Al5TiB master alloy is unsuitable refiner with mischmetal modification.
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