12t级Ti80合金铸锭的成分均匀性及其偏析规律  

Uniformity and Segregation in 12t Ingot of Ti80 Alloy

作　　者：杜玉俊 刘向宏[1] 李金山[2] 罗文忠[1] 杨晶[1] 陈海生 Du Yujun;Liu Xianghong;Li Jinshan;Luo Wenzhong;Yang Jing;Chen Haisheng(Western Superconducting Technologies Co.,Ltd,Xi'an 710018,China;State Key Laboratory of Solidification Processing,Northwestern Polytechnical University,Xi'an 710072,China)

机构地区：[1]西部超导材料科技股份有限公司,陕西西安710018 [2]西北工业大学凝固技术国家重点实验室,陕西西安710072

出　　处：《稀有金属材料与工程》2020年第3期883-889,共7页Rare Metal Materials and Engineering

基　　金：中国博士后科学基金(2017M613234);陕西省博士后科研项目(2017BSHQYXMZZ01)。

摘　　要：利用Melt Flow模拟获得优化的熔炼工艺,制备出国内第1个12t级Ti80合金铸锭,并完成2炉稳定性验证。成分检测结果表明,铸锭头、中、尾3点成分极差小于1000μg/g,冒口17点成分极差小于3000μg/g,成分均匀性与现行5t级铸锭基本相当。分析冒口径向成分分布规律发现,Al、Nb和Mo元素呈现边部高、心部低,从边部到心部逐渐降低的趋势,而Zr元素的分布规律则与之相反。利用EDS对不同部位晶内和晶界的微区成分分析发现,Nb、Mo元素呈现晶内高、晶界低,而Al、Zr元素呈现晶内低、晶界高的分布规律。其中,Nb、Mo、Zr元素的宏、微观偏析规律基本一致,即随着凝固的进行,固相中Mo、Nb含量逐渐降低,Zr含量逐渐升高。然而,Al元素的宏、微观偏析规律正好相反,分析认为主要是由于Al元素的饱和蒸气压较高,与其他合金元素相比更容易挥发,在长时间、高真空熔炼和溶质再分配的共同作用下,铸锭中的宏、微观偏析规律出现不一致的现象。Based on the simulation results by Melt Flow, the 1 st 12 t ingot of Ti80 alloy was melted in China and then was verified by two times. The chemical testing results show that the composition difference of the upper, middle and bottom of the ingot is less than 1000 μg/g, and the composition difference of the 17 positions of the riser is less than 3000 μg/g. Both of them are equivalent to that of the 5 t ingot. Further, the macrosegregation at the riser was investigated and it is found that Al, Nb, Mo are enriched in the edge of the ingot and poor in the center of the ingot, whereas Zr has an opposite phenomenon. Microsegregation between the grain boundary and interior were studied by EDS. The results show that Nb and Mo are enriched within grains and poor at grain boundary. On the contrary, Al and Zr are enriched at grain boundary and poor within grains. The macro and micro segregation are consistent for Nb, Mo and Zr and opposite for Al. This is largely because the distribution of Nb, Mo and Zr is more depended on the solute redistribution at the solidification interface. By contrast, due to the high saturated vapor pressure at high temperature, Al is volatilized severely during the long time and high vacuum melting process and the solute redistribution is at the solidification interface.

关 键 词：12t级 Ti80合金 成分均匀性 偏析规律 

分 类 号：TG146.23[一般工业技术—材料科学与工程]