论文部分内容阅读
采用LMC高梯度定向凝固和微观分析方法,研究了不同凝固速率下IN718合金的凝固组织和偏析行为。结果表明,随着凝固速率的提高,凝固界面由胞晶转为枝晶;一次胞/枝晶间距在凝固速率为20μm/s时提高到最大值257μm,随后逐渐降低,二次枝晶间距明显细化,溶质分配比也随凝固速率的增加而减小。同时,凝固速率增加使糊状区枝晶骨架的渗透性减小,增大了对液体流动的阻碍作用。
The solidification microstructure and segregation behavior of IN718 alloy at different solidification rates were studied by LMC high gradient directional solidification and microscopic analysis. The results show that with the increase of solidification rate, the interface of solidification is transformed from dendrites to dendrites. The primary cell / dendrite spacing increases to the maximum of 257μm at a solidification rate of 20μm / s, and then decreases gradually with obvious secondary dendrite spacing Refinement, solute distribution ratio also decreases with increasing solidification rate. At the same time, the increase of the solidification rate reduces the permeability of the dendritic framework in the mushy zone and increases the impediment to the liquid flow.