论文部分内容阅读
研究了静态和切向流动作用下对二氯苯-丁二腈(DCB-SCN)偏晶合金的定向凝固过程.实验结果表明,静态条件下,DCB以小平面相方式生长,随着抽拉速度的提高,DCB-SCN偏晶凝固组织形貌发生液/固两相完全分离组织-规则纤维状共生组织-不规则弥散组织转变.施加切向流动作用后,DCB生长晶面出现胞状扰动,并且偏晶共生纤维间距随流速的增高而变大,但对于同一流速,仍然满足λV0.5=常数.同时,切向流动能够细化弥散偏晶组织中第二相颗粒尺寸,这主要缘于流动引发的固液界面形态变化能够提高第二相液滴的形核率以及阻碍第二相液滴之间的凝并。
The directional solidification of DCB-SCN monotectic alloy under static and tangential flow was studied. The experimental results show that DCB grows in a small plane phase under static condition, , The disordered solid-liquid two-phase completely separated structure-regular fibrous symbiosis-irregular dispersion structure of DCB-SCN was observed in the dendritic solidification morphology of DCB-SCN.When the tangential flow was applied, the cell- The intergranular fiber spacing increases with the increase of flow rate, but still satisfies λV0.5 = constant for the same flow rate. Meanwhile, the tangential flow can refine the second phase particle size in the dispersed meta-crystal structure, mainly due to the flow The induced morphological changes of the solid-liquid interface can increase the nucleation rate of the second-phase droplets and impede the condensation between the second-phase droplets.