定向凝固用BaZrO3复合模壳致密性及抗TiAl侵蚀性  

Compactness and Corrosion Resistance of BaZrO3 Composite Mould for Directional Solidification of TiAl Alloy

作　　者：李凯 熊富豪 陈光耀[2] 张如林[3] 鲁雄刚 李重河 Li Kai;Xiong Fuhao;Chen Guangyao;Zhang Rulin;Lu Xionggang;Li Chonghe(State Key Laboratory of Advanced Special Steel&Shanghai Key Laboratory of Advanced Ferrometallurgy&School of Materials Science and Engineering,Shanghai University,Shanghai 200072,China;Materials Genome Institute of Shanghai University,Shanghai 201900,China;Shanghai Dianji University,Shanghai 201306,China;Shanghai Special Casting Engineering Technology Research Center,Shanghai 201605,China)

机构地区：[1]上海大学材料科学与工程学院省部共建高品质特殊钢冶金与制备国家重点实验室上海市钢铁冶金新技术开发应用重点实验室,上海200072 [2]上海大学材料基因组研究所,上海201900 [3]上海电机学院,上海201306 [4]上海特种铸造工程技术研究中心,上海201605

出　　处：《稀有金属材料与工程》2019年第11期3548-3555,共8页Rare Metal Materials and Engineering

基　　金：国家自然科学基金(51574164,U1760109);上海市科委基金项目(14JC1491400);中国博士后科学基金资助项目(2018M632081)

摘　　要：TiAl合金具有高化学活性,与传统的耐火材料会发生不同程度的化学反应,并限制其在定向凝固铸件中的生产应用。以自合成的BaZrO3粉料作为模壳面层耐火材料(钇溶胶为粘结剂),Al2O3为背层耐火材料(硅溶胶为粘结剂)制备BaZrO3复合模壳。研究BaZrO3粒度对模壳面层致密性的影响、合金定向凝固过程后渗透层形貌以及合金中的污染元素含量。通过光学显微镜(OM)、扫描显微镜(SEM)、能谱(EDS)仪、X射线衍射(XRD)仪、阿基米德原理、电感耦合等离子体发射光谱仪(ICP)和氮氧仪(IGI,LECO TC-436)等手段分析面层微观组织结构及孔隙率、模壳与合金界面组织形貌以及成分、合金污染元素的含量。结果表明,细粒度颗粒作为涂层的模壳经过高温烧结后涂层表面更加致密光滑,颗粒之间孔隙数量减少及尺寸减小,孔隙率由优化前的17.3%降低为13.5%;优化后模壳的面层厚度从1000μm(2层)提高为3500μm(4层);BaZrO3面层与Al2O3背层之间的粘结层厚度从300μm提高至1200μm,面层与背层基体粘结性增强;优化后模壳与合金的界面渗透层从优化前的900μm降低为300μm,合金熔体的渗透被限制在模壳面层,无合金液渗入背层;合金中的Ba、Zr、O含量由89、16800、7586μg/g减小为28、4760、3690μg/g。Chemical reaction of different degrees can occur for TiAl alloys with traditional refractory materials due to the high activity of TiAl alloys,which restricts their application in directional solidification castings.In this paper,the BaZrO3 composite mould was prepared by self-synthesized BaZrO3 powder as the surface layer(yttrium sol as a binder),Al2O3 as a back layer(silica sol as a binder).The influence of BaZrO3 particle size on the compactness of the mould,the morphology of penetration layer after directional solidification of the alloy,and the contaminant content in the alloy were investigated.The evolution of the microstructure of the surface layer and porosity,the interaction between the mould and the alloy,the morphology and composition of the interface,and the contaminant content of the alloy were investigated by an optical microscope(OM),scanning electron microscopy(SEM),energy dispersive X-ray spectroscopy(EDS),X-ray diffraction analysis(XRD),Archimedes’principle,Inductively Coupled Plasma(ICP)and Nitrogen and oxygen analyzer(IGI,LECO TC-436).The results show that the surface of the mould using fine-grained particles as the coating is denser and smoother after sintering at high temperature,the number of pores between particles is reduced and the size decreases,the porosity of the surface layer decreases from 17.3%to 13.5%.The surface layer thickness of the optimized mould is from 1000μm(2 layers)to 3000μm(4 layers).The thickness of the adhesive layer between the BaZrO3 surface layer and the Al2O3 back layer is increased from 300 to 1200μm,and the adhesion is also enhanced.The interface penetration layer between the optimized mould and alloy is reduced from 900 to 300μm,the penetration of the alloy melt is limited within the surface layer,and no exudate is observed in the back layer.The content of Ba,Zr,O in the alloy are reduced from 89,16800,7580 to 28,4760,3690μg/g.

关 键 词：TIAL合金 BaZrO3 致密性 界面渗透层 

分 类 号：TB333.2[一般工业技术—材料科学与工程]