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根据柱状晶向等轴晶转变(CET)图,建立了激光熔池横截面的几何关系,得出了选区激光熔化(SLM)镍基单晶高温合金的凝固条件与显微组织的关系,并在SRR99单晶基板的(100)晶面上沿[001]方向进行了SLM实验。结果表明,当激光功率为160 W、铺粉层厚为20μm、扫描速率V_b≤30m·min~(-1)时,凝固速度与激光扫描速度的夹角最小值为46.4°(大于45°)。可以预测激光熔池组织仅由熔池底部向顶部生长的[001]枝晶和熔池两侧的[010]枝晶组成,实验结果与理论分析结果相吻合,且层间形成了良好的冶金结合,基层的结晶取向得到延续。
According to the columnar equiaxed crystal transformation (CET) diagram, the geometrical relationship of the cross section of the laser pool was established, and the relationship between the solidification conditions and the microstructure of the selected laser melting (SLM) nickel base single crystal superalloy was obtained. The SLM experiment was performed in the [001] direction on the (100) crystal plane of the SRR99 single crystal substrate. The results show that when the laser power is 160 W, the layer thickness is 20 μm and the scanning rate is V_b ≤ 30 m · min -1, the minimum value of the included solidification speed and laser scanning speed is 46.4 ° (greater than 45 °) . It can be predicted that the [001] dendrites and the [010] dendrites on both sides of the melt pool in the molten pool are only formed from the bottom to the top of the melt pool. The experimental results are in good agreement with the theoretical analysis results and good metallurgical In combination, the crystal orientation of the base layer is continued.