采用 Al-(3．4—15)%Bi(质量分数)难混溶合金进行了快速连续凝固实验,研究了 Bi 含量和凝固速率对快速连续凝固组织的影响．结果表明,少量富 Bi 相粒子尺寸随着 Bi 含量的增加而增大,提高凝固速率有助于制备少量富 Bi 相粒子均匀分布的...采用 Al-(3．4—15)%Bi(质量分数)难混溶合金进行了快速连续凝固实验,研究了 Bi 含量和凝固速率对快速连续凝固组织的影响．结果表明,少量富 Bi 相粒子尺寸随着 Bi 含量的增加而增大,提高凝固速率有助于制备少量富 Bi 相粒子均匀分布的难混溶合金．通过分析富 Bi 粒子尺寸分布,发现沿试样轴向和径向方向粒子平均直径变化不大,试样表层处粒子尺寸较小．研究表明,快速连续凝固是制备均质难混溶合金的有效途径．展开更多
Effects of mold electromagnetic stirring （M-EMS） on the solidification structure of 45# steel billet were investigated by examination of interdendritic corrosion. The results show that the primary and secondary dend...Effects of mold electromagnetic stirring （M-EMS） on the solidification structure of 45# steel billet were investigated by examination of interdendritic corrosion. The results show that the primary and secondary dendrite arm spacings increase from the edge of the billet to the center and decrease obviously with increasing electromagnetic torque, which will be beneficial to refine the solidification structure and enlarge the equiaxed crystal zone. The ratio of equiaxed crystal increases by 15.9% with the electromagnetic torque increasing from 230 to 400 cN·cm. The increase of stirring intensity can improve the cooling rate and the impact of M-EMS on it reduces from the edge of the billet to the central area, where the cooling rates are similar at different torques. The closer to the central area, the less the influence of M-EMS on the cooling rate is. The ratio of the primary to secondary dendrite arm spacing is approximately 2.0, namely, λ1≈2λ2, and is constant irrespective of the stirring intensity and position of the billet. Original position analysis （OPA） results indicate that the center segregation of the billet is greatly improved, and the more uniform and compact solidification structure will be obtained with the increase of stirring intensity.展开更多
文摘采用 Al-(3．4—15)%Bi(质量分数)难混溶合金进行了快速连续凝固实验,研究了 Bi 含量和凝固速率对快速连续凝固组织的影响．结果表明,少量富 Bi 相粒子尺寸随着 Bi 含量的增加而增大,提高凝固速率有助于制备少量富 Bi 相粒子均匀分布的难混溶合金．通过分析富 Bi 粒子尺寸分布,发现沿试样轴向和径向方向粒子平均直径变化不大,试样表层处粒子尺寸较小．研究表明,快速连续凝固是制备均质难混溶合金的有效途径．
文摘Effects of mold electromagnetic stirring （M-EMS） on the solidification structure of 45# steel billet were investigated by examination of interdendritic corrosion. The results show that the primary and secondary dendrite arm spacings increase from the edge of the billet to the center and decrease obviously with increasing electromagnetic torque, which will be beneficial to refine the solidification structure and enlarge the equiaxed crystal zone. The ratio of equiaxed crystal increases by 15.9% with the electromagnetic torque increasing from 230 to 400 cN·cm. The increase of stirring intensity can improve the cooling rate and the impact of M-EMS on it reduces from the edge of the billet to the central area, where the cooling rates are similar at different torques. The closer to the central area, the less the influence of M-EMS on the cooling rate is. The ratio of the primary to secondary dendrite arm spacing is approximately 2.0, namely, λ1≈2λ2, and is constant irrespective of the stirring intensity and position of the billet. Original position analysis （OPA） results indicate that the center segregation of the billet is greatly improved, and the more uniform and compact solidification structure will be obtained with the increase of stirring intensity.
