中文摘要：

演员组 Ti-46Al 合金的团结结构上的 Hf 和 B 的影响被调查。结果证明 Hf 和 B 的联合效果改变团结结构形态学并且强烈精制谷物尺寸。Hf+B 什么时候满足，从 0 + 被增加 0.0 ～ 3 + 0.2， 5 + 0.6 和 7 + 1.0 (在里面在。%)，团结结构形态学从粗糙的圆柱的树突改变了到好圆柱的树突，然后到 equiaxed 树突，并且虽然平均谷物尺寸减少了到 20 m.It ，推进在小粒的谷物附近罚款被结束圆柱的树突精炼在melt 的艾尔散开系数在减少中由于 Hf 和 B 的效果。好近小粒的谷物形成被归因于被 Hf 和 B 增加在固体 / 液体的接口 uring 团结加强的 AI 和 B 分离形成的联合宪政的 supercooling，并且 TiB2 猛抛充当异构的原子核。

英文摘要：

The influence of Hf and B on the solidification structure of cast Ti-46Al alloys was investigated. The results show that the coupling effect of Hf and B changes the solidification structure morphology and strongly refines the grain size. When the Hf＋B contents were increased from 0 ＋ 0.0 to 3 ＋ 0.2, 5 ＋ 0.6 and 7 ＋ 1.0 （in at. %）, the solidification structure morphology changed from coarse columnar dendrite to fine columnar dendrite, then to equiaxed dendrite, and further to fine near granular grain whilst the average grain size decreased to 20 μm. It is concluded that the columnar dendrite refinement is due to the effect of Hf and B on the decrease of AI diffusion coefficient in the melt. The fine near granular grain formation is attributed to the combined constitutional supercooling formed by AI and B segregation that is strengthened by Hf and B additions at the solid/liquid interface during solidification, and the TiB2 precipitates acting as heterogeneous nuclei.