中文摘要：

研究了纯Ni、Ni-12％Cr和DD483合金分别作为籽晶定向生长镍基单晶高温合金的凝固过程。结果表明，纯Ni和Ni-12％Cr籽晶的凝固界面历经平界面-胞状界面-枝晶界面的转变过程，采用树枝晶的DD483籽晶时，凝固界面直接由籽晶重熔区进入枝晶生长阶段。单晶高温合金的晶体取向延续了籽晶的晶体取向，但纯Ni籽晶／高温合金界面处的晶体取向发生小角度偏转。分析认为，这是由于成分突变引起γ相的晶格常数发生变化所造成的，

英文摘要：

Directional solidification of single crystal superalloy by using seeds of pure Ni, Ni- 12% Cr and DD483 alloys were investigated, respectively. The experimental results showed that the solid/liquid interface changed from planar to cellular, and then to dendrite during the directional solidification process by using the pure Ni and Ni-12% Cr seeds, separately. When the DD483 alloy seed was used, the solidification interface transformed from seed melt-back zone into dendrite directly. The single crystal castings kept the orientation of bottom seeds in the dendrite growth stage. There was a small angle deviation from the seed orientation near pure Ni seed/DD483 superalloy interface. This may be due to the change of lattice constant of γ phase caused by compositions variation.