【摘要】 采用光学浮区定向凝固炉,对Ti-43Al-3Si合金进行引晶定向生长研究.从直径70 mm铸棒中切取直径9 mm多晶棒为籽晶,在5 mm/h的速度下引晶生长出了微观片层平行于生长方向的定向合金.采用OM对获得试样的组织进行观察,结果表明,在开始凝固的L+α+β三相共存区中,多晶棒有效引晶并控制了心部α相,并在曲面生长条件下逐渐发展成为占据主导地位的组织结构.对实验中多晶籽晶的选取、三相共存及曲面生长原理进行了深入讨论.更多还原

【Abstract】 Directional solidification(DS) process of Ti-43Al-3Si alloys in an optical floating zone furnace has been studied.The #9 mm polycrystalline rods with appropriate microstructure were cut from <?70 mm cast ingot and used as seeds.At a growth rate of 5 mm/h,the DS ingot with lamellar structure parallel to longitudinal axis was obtained.The results of OM show that in the L+a+/3 three-phase region,the central a phase was successfully seeding by the polycrystalline rods and gradually develops into a dominant microstructure under a bent solid-liquid interface.The selec- tion of polycrystalline seed,principle of three-phase region and bent solid-liquid interface directional solidification were discussed in detail.更多还原