TiAl基合金金属型真空吸铸成形方法研究

Study on Vacuum Suction Casting for TiAl-Based Alloys

摘要:

提出了一种钛铝基合金金属型真空吸铸成形新方法，并通过数值模拟研究了TiAl基合金薄板、叶片的充型规律。研究表明，在真空吸铸过程中，充型速度和石墨吸口直径的增加，有利于充型分数的提高，另外石墨吸口直径与反向充填出现的位置密切相关。在凝固过程中，合金从下而上逐层凝固，但随着铸型温度的增加，凝固了的合金在金属液中所占的比例减少。以数值模拟结果指导试验，得到质量良好的TiAl基合金薄板和叶片铸件

关键词:真空吸铸;数值模拟;石墨吸口直径;凝固分数;充型分数

Abstract:

A novel type of foundry method for TiAl-based alloy is presented in the present paper. The filling processes of Ti-47Al alloy sheet and blade have been studied via numerical simulation. The investigation results indicate that the filling fraction is enhanced by the increase of filling velocity and graphite throat diameter. The graphite throat diameter is the main parameter for the backward filling location in the process of vacuum suction casting. With the increase of mould temperature, the solid fraction is reduced. The alloy solidification begins from bottom to top. The TiAl sheet and the blade are produced by this method. The grain size of the sheet is in the range from 10 μm to 40 μm. There is no obvious shrinkage cavity

Key words:vacuum suction casting; numerical simulation; graphite throat diameter; solid fraction; filling fraction