BaZrO_(3)/Y_(2)O_(3)复合耐火材料制备及其与TiAl合金界面反应研究

Preparation of BaZrO_(3)/Y_(2)O_(3) Composite Refractory and Its Interaction with TiAl Alloy

使用电熔BaZrO_(3)耐火材料和Y_(2)O_(3)耐火材料复合,在1650℃保温24h烧制成坩埚,感应熔炼制备TiAl合金。通过X射线衍射仪(XRD)、扫描电子显微镜(SEM)结合能谱仪(EDS)、电感耦合等离子体原子发射光谱法(ICP-AES)和氧/氮分析仪等手段分析了复合坩埚耐火材料相结构和显微结构,研究了复合耐火材料坩埚与TiAl合金熔体界面反应。结果表明,复合坩埚耐火材料由Zr固溶Y_(2)O_(3)和Y掺杂BaZrO_(3)两相组成,Y_(2)O_(3)的引入提高了电熔BaZrO_(3)耐火材料稳定性。熔解侵蚀作用是复合坩埚耐火材料与TiAl合金熔体界面作用机制,但游离Al_2O_3仍会与分解的BaO反应生成BaAl_(2)O_(4)附着在坩埚内壁;熔炼制备TiAl合金锭中氧含量仅为0.0986%(质量分数),与理论计算值相一致,且符合工业用TiAl合金铸锭用氧含量标准,表明了电熔BaZrO_(3)/Y_(2)O_(3)是一种极有潜力的TiAl合金感应熔炼制备用耐火材料。

The composite refractory crucible was fabricated after sintering at 1650℃for 24 h using the fused BaZrO_(3) and Y_(2)O_(3),and then induction melting of TiAl alloy was carried out in the crucible.By the X-ray diffraction,scanning electron microscope combined with the energy disperse spectroscopy,inductively coupled plasma atomic emission pectrometry and O/N analyzer,the phase composition and micro structure of the composite refractory were investigated as well as the interaction between the composite crucible and TiAl alloy melt.The results reveal that the composite crucible is composed of Y doped BaZrO_(3) and Y_(2)O_(3)(ZrO_(2))phases,and the introduce of Y_(2)O_(3) helps to the improvement of fused BaZrO_(3) refractory.Dissolution-erosion is responsible for the interaction between the refractory and TiAl alloy melt,while the Al2 O3 in the melt reacts with the BaO,leading to the generation of reactant BaAl_(2)O_(4) which attaches to the inner wall of the crucible.The oxygen concentration for the prepared TiAl alloy ingot is about 0.0986 wt%,which is consistent with the calculated value for the TiAl alloy.It also meets the criteria for the industrial TiAl alloy ingot,indicating that the BaZrO_(3)/Y_(2)O_(3) composite refractory is the candidate for induction melting of TiAl alloys.