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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。
Ti-46Al-8Nb alloy was directionally solidified by BaZrO_3 composite shell. The interface between BaZrO_3 refractory and metal melt was analyzed by means of scanning microscope, metallographic microscope and XRD. The number of grains and the change of layer after the melt passed through spiral selector were analyzed. Included angle and the microstructure of Ti-46Al-8Nb alloy after solidification. The results show that there is a diffusion layer of about 10μm between the BaZrO_3 composite shell and the Ti-46Al-8Nb alloy. The primary phase of the Ti-46Al-8Nb alloy at the pull rate of 7.7 mm / min and the temperature of 1 550 ℃ is α phase and β phase. The microstructures after directional solidification are γ + α 2 lamellae, γ phase and B2 phase. During the directional solidification, the number of crystal grains can be significantly decreased by helical crystal selection. However, no effect.