BaZrO_3复合型壳定向凝固Ti-46Al-8Nb合金的微观组织研究  

Study on Microstructures of Directional Solidified Ti-46Al-8Nb in BaZrO_3-based Mould

作　　者：李明阳[1] 张浩[1] 王树森[1] 魏超[1] Wajid 秦子威 鲁雄刚[1,2] 汪宏斌[1,2] 李重河[1,2] 

机构地区：[1]上海大学省部共建高品质特殊钢冶金与制备国家重点实验室,上海200072 [2]上海特种铸造工程技术研究中心,上海201605

出　　处：《钛工业进展》2016年第3期18-23,共6页Titanium Industry Progress

基　　金：国家自然科学基金项目(51225401;51374142);国家973计划项目(2014CB643403);上海市科委基金项目(11DZ2283400;14JC1491400)

摘　　要：采用BaZrO_3复合型壳定向凝固Ti-46Al-8Nb合金。通过扫描显微镜、金相显微镜和XRD等手段分析了BaZrO_3耐火材料与金属熔体之间的界面情况、熔体通过螺旋选晶器后的晶粒数目和片层变化、晶臂与枝晶干的夹角以及凝固后Ti-46Al-8Nb合金的组织形貌。结果表明,BaZrO_3复合型壳与Ti-46Al-8Nb合金之间存在约为10μm的扩散层;在抽拉速度7.7 mm/min、温度1 550℃条件下,Ti-46Al-8Nb合金的初生相为α相以及β相,经过定向凝固后的微观组织为γ+α_2片层、γ相以及B2相;在定向凝固过程中,螺旋选晶可以明显使晶粒数目减少,但是对片层间距的大小无影响。BaZrO3-based mould was used in directional solidification of Ti-46Al-8Nb. The interface between BaZrO3 and metal melt, the number of grains and change of lamella in spiral crystal converter, the angle between dendrite arms and second dendrite arm, and microstructure of solidified Ti-46Al-8Nb were investigated by scanning electron microscope, optical microscope and X-ray diffraction. The results show that a 10 μm-wide diffusion layer is found between BaZrO3-based mould and Ti-46Al-8Nb alloy. The primary phases of Ti-46Al-8Nb alloy are α phase and β phase, while the microstructures of solidified alloy are （γ ＋ α2 ） ＋ γ ＋ B2 phase. The number of grains decreases in spiral crystal converter during directional solidification, while the thickness of lamella does not change.

关 键 词：BaZrO3复合型壳 Ti-46Al-8Nb合金 定向凝固 

分 类 号：TG146.23[一般工业技术—材料科学与工程]