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采用高能激光束作为定向凝固的热源,研究了镍基合金在超高温度梯度(1.0×104K/cm)定向凝固下的组织结构特征。在定向凝固组织中得到了平均一次枝晶间距仅为10.6μm的细枝晶和完全无侧向分枝的“超细胞晶”。对合金元素在不同组织中偏析行为的分析表明:传统的定向凝固组织中存在严重的微观偏析,而激光超高温度梯度定向凝固组织中,元素的微观偏析大大改善甚至完全消除。
The high-energy laser beam was used as the heat source for directional solidification. The microstructure of nickel-base alloy under directional solidification with ultrahigh temperature gradient (1.0 × 104K / cm) was studied. In the directionally solidified tissue, fine dendrites with an average primary dendrite spacing of only 10.6 μm and “supercrystalline cells” with no dendrites were obtained. The analysis of the segregation behavior of alloying elements in different tissues shows that there is serious microsegregation in the conventional directional solidification microstructure, and the micro-segregation of elements in the ultra-high temperature gradient directional solidification structure is greatly improved or even completely eliminated.