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控制柱状晶生长方向,实现任意方向的定向凝固,这对提高铸件性能具有重要意义。本文用类金属透明有机合金莰烯—1.2％环己醇,在定向凝固条件下,连续改变热流方向,在显微镜下直接观察结晶过程以探索控制柱状晶生长方向的可能性和途径。实验结果表明,当温度梯度G和生长速率R的比值G/R>8×10~(50)C·s/cm~2时,固液界面为稳定的平面状。当G/R=5×10~(50)C·s/cm~2时,固液界面开始由平面状转向胞状形态。在界面不断旋转的过程中,平面状形态几乎不发生变化,临界胞状形态只有微小的变化,说明在这些界面形态中,晶体位向的影响很小。
Controlling the growth direction of columnar crystals to achieve directional solidification in any direction is of great significance to improve the performance of castings. In this paper, the direction of heat flux is continuously changed under the condition of directional solidification, and the crystallization process is directly observed under the microscope to explore the possibility and ways of controlling the growth direction of columnar crystals. The experimental results show that when the ratio of temperature gradient G to growth rate G / G> 8 × 10 ~ (50) C · s / cm ~ 2, the solid-liquid interface is stable. When G / R = 5 × 10 ~ (50) C · s / cm ~ 2, the solid-liquid interface began to turn from planar to cellular morphology. In the process of continuous rotation of the interface, the planar morphology almost does not change, the critical cell morphology changes only slightly, indicating that in these interface morphology, the influence of the crystal orientation is small.