Crystal structure selection

1.在包晶合金的单向凝固过程中，观察到两组分相在生长方向上波动的周期性组织。本研究在高达10T的磁场下进行了定向凝固，并表明通过减少对流可以更好地观察到周期性结构。结果表明，周期系统涉及周期生长模式。磁各向异性导致的排列结构的形成本研究开发了新的处理方法来获得磁排列结构。在校直过程中，采用快速凝固产生的非平衡组织作为起始材料。加热非平衡结构的Bi-Mn体系使其处于半固态状态，而传统的凝固过程可以获得半固态。通过在半固态上施加磁场，实现了BiMn化合物的定向。此外，在磁场作用下粗化得到了排列结构的BiMn。本研究利用非平衡结构提出了取向机理。单晶合金凝固组织的控制单晶合金存在液态不混溶间隙。一般情况下，由于两相密度差引发强对流，导致宏观偏析，难以获得均匀细小的凝固组织。本研究表明，施加10T的磁场可以显著减少Cu-Pb合金的对流，从而使Cu-Pb合金产生均匀的凝固组织；施加2T以上的磁场可以使Al-In合金单向凝固，得到与规则共晶组织基本相似的棒状单晶组织。施加强磁场是获得均匀凝固组织的有效方法。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