Crystal structure selection

1.包晶合金定向凝固中周期性组织的形成在包晶合金的定向凝固过程中，观察到两个组分沿生长方向波动的周期性组织。在高达10T的磁场下进行了定向凝固实验，结果表明，通过减少对流，可以较好地观察到周期性组织。结果表明，周期系统包含周期增长模式。由于磁各向异性而形成的取向结构本研究开发了获得磁性取向结构的新工艺。在取向过程中，采用快速凝固产生的非平衡组织作为起始材料。加热BiMn系的非平衡组织导致了半固态，而在常规凝固过程中可以得到半固态。通过在半固态上施加磁场，BiMn化合物…的取向取得了更多的成果。此外，在磁场作用下粗化得到了定向排列的BiMn结构。本研究利用非平衡结构提出了对齐的作用机制。偏晶合金凝固组织的控制偏晶合金存在液态不混溶间隙。一般情况下，由于两液相之间的密度差异会引发强烈的对流并导致宏观偏析，因此很难获得均匀细小的凝固组织。研究表明，外加10T的磁场可显著减少铜铅合金的对流，从而产生均匀的凝固组织。在Al-In合金定向凝固的情况下，外加2T以上的磁场可获得与规则共晶组织基本相似的棒状偏晶组织。施加强磁场可以有效地获得偏晶组织的均匀凝固组织。较少

1.Periodic structure formation during unidirectional solidificationDuring unidirectional solidification of peritectic alloys, periodic structures in which faction of two constituent phases fluctuates in the growth direction have been observed. This study performed unidirectional solidification under a magnetic field up to 10T and indicated that the periodic structure was preferably observed by reducing convection. The results indicated that the periodic systems involved the periodic growth mode.2. Aligned structure formation due to the magnetic anisotropyThis study developed novel processing to obtain the magnetically aligned structure. In the alignment procedures, non-equilibrium structure produced by rapid solidification was used as a starting material. Heating the non-equilibrium structure of Bi-Mn system caused the semisolid state, while can be obtained during conventional solidification procedure. By imposing the magnetic field on the semisolid state, alignment of the BiMn compoun … More d were achieved. Furthermore, the aligned structure of BiMn was obtained during coarsening under a magnetic field. This study proposed mechanism of the alignment by using the non-equilibrium structure.3. Control of solidified structure of monotectic alloysThere is immiscibility gap of liquid state for monotectic alloys. In general, it is difficult to obtain uniform and fine solidified structure, since density difference between the two liquid phases initiates strong convection and leads to macrosegregation. This study indicated that imposition of a magnetic field, 10T, significantly reduced convection and consequently produced homogenous solidified structure for Cu-Pb alloysIn the case of unidirectional solidification for Al-In alloys, rod-type monotectic structure, which was basically similar to the regular eutectic structure, was obtained by imposing a magnetic field more than 2T. Imposition of the high magnetic fields was effective to obtain homogenous solidified structure for monotectic systems. Less