In-situ Observation of Engulfment and Pushing of Small Particl in Molten Metal by Advancing Melt/Solid Interface

通过推进熔体/固体界面现场观察熔融金属中小颗粒的吞噬和推动

• 批准号: 09650804
• 负责人: SHIBATA Hiroyuki
• 金额: $ 2.18万
• 依托单位: TOHOKU UNIVERSITY
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (C)
• 财政年份: 1997
• 资助国家: 日本
• 起止时间: 1997 至 1998
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-09650804/
• 关键词: steel; solid; liquid interface; engulfment; pushing; inclusion; confocal scanning microscope; phase transformation; 補足

Engulfment or pushing of inclusion particle by advancing melt/solid interface of steel has been investigated in-situ with a confocal scanning laser microscope. When the velocity of advancing interface exceeds a critical value for a particle, solid alumina cluster particle or liquidsilicate/aluminate globular particle in steel melt is found engulfed by the interface which extends in a convex way to form a bump toward the particle. At lower velocities or for smaller radii, the particles in both classes are pushed by the interface which does not form the bump. The shape of the bump is reasonably reproduced by a two-dimensional FEM analysis of heat transfer from the melt across the particle to the interface. Reduced heat transfer caused by the intervening particle is considered responsible for the engulfment.We also show that. the smaller alumina inclusions are not entrapped in the dendritic solid during solidification, based on estimates of the interdendritic solidification rates and empi … More rical data on the engulfment of alumina inclusions by solidifying steel. Engulfment by the interdendritic liquid however is enhanced by the gradients of the concentrations of oxygen and sulfur in the interdendritic liquid during solidification. These elements are surface active on the liquid-steel/alumina interface and m turn introduce very strong capillary forces on the interdendritic alumina inclusions.Phase transformation of delta-ferrite/gamma-austenite in low carbon steels was observed. Dihedral angles at triple points of one high energy delta/delta grain boundary and two incoherent delta/gamma interphase boundaries were measured. From the average value of observed dihedral angles, free energy of gamma/delta incoherent. boundary for a steel with low sulfur content on the dihedral angle and free energy of incoherent, d/g boundary were discussed. At. the same time. the dendritic growth of gamma-phase was observed and analyzed by the constitutional supercooling and instability theories. which show good agreement between the observations and theories. Less

当前进界面的速度超过颗粒、固体氧化铝簇颗粒或液体硅酸盐/铝酸盐球状的临界值时，用共焦扫描激光显微镜现场研究了通过前进钢熔体/固体界面来吞噬或推动颗粒夹杂物。发现钢熔体中的颗粒被界面吞没，界面以凸面方式延伸，形成朝向颗粒的凸块。在较低速度或较小半径下，两类颗粒都被界面推动。不形成凸块的形状通过对从熔体穿过颗粒到界面的热传递的二维有限元分析合理地再现了由介入颗粒引起的热传递减少被认为是导致吞没的原因。我们还表明，根据枝晶间凝固速率的估计和有关氧化铝夹杂物吞噬的经验数据，较小的氧化铝夹杂物在凝固过程中不会被捕获。然而，在凝固过程中，枝晶间液体中氧和硫的浓度梯度增强了枝晶间液体的吞没，这些元素在液态钢/氧化铝界面上具有表面活性，进而引入非常强的毛细管力。观察到低碳钢中δ铁素体/γ奥氏体在一个高能三相点处的二面角相变。根据观察到的二面角的平均值，测量了δ/δ晶界和两个非相干δ/γ相界，测量了低硫含量钢的二面角上的γ/δ非相干晶界自由能和非相干自由能。同时对γ相的枝晶生长进行了观察和分析，结果表明。观察结果和理论之间的一致性较差。

项目成果

Hongbin YIN: "Determination of Free Energy of δ-Ferrite/γ-Austenite Interphase Boundary of Low Carbon Steels by In-Situ Observation" ISIJ International. 38. 794-801 (1998)

尹宏斌：“通过原位观察测定低碳钢 δ-铁素体/γ-奥氏体相间边界的自由能”ISIJ International 38. 794-801 (1998)。

Hongbin YIN: "Morphological Instability of g-Fernte/r-Austenite Interphase Boundary in Low Carlon Steels" Acta mater. in press. (1999)

尹宏斌：“低卡隆钢中 g-Fernte/r-奥氏体界面边界的形态不稳定性”学报。

Hiroyuki SHIBATA,Hongbin VIN,Satoru YOSHINAGA,Toshihiko EMI and Mikio SUZUKI: "In-situ Observation of Engulfment and Pushing of Nonmetallic Inclusions in Steel Melt by Advancing Melt/Solid Interface" ISIJ International.38. 149-156 (1998)

Hiroyuki Shibata、Hongbin VIN、Satoru YOSHINAGA、Toshihiko EMI 和 Mikio SUZUKI：“通过推进熔体/固体界面对钢液中非金属夹杂物的吞没和推动进行原位观察”ISIJ International.38。

Hongbin YIN.Toshihiko EMI and Hiroyuki SHIBATA: "Determination of Free Energy of delta-Ferrite/gamma-Austenite Interphase Boundary of Low Carbon Steels by In-situ Observation" ISIJ International. 38. 794-801 (1998)

Hongbin YIN.Toshihiko EMI 和 Hiroyuki Shibata：“通过原位观察测定低碳钢 δ-铁素体/γ-奥氏体界面边界的自由能”ISIJ International。

Hongbin YIN: "Morphological Instability of δ-Ferrite/γ-Austenite Interphase Boundary in Low Carbon Steels" Acta mater.47. 1523-1535 (1999)

尹宏斌：“低碳钢中δ-铁素体/γ-奥氏体相界面的形态不稳定性”Acta mater.47 1523-1535 (1999)。