Grant-in-Aid for Scientific Research on Priority Areas (B).
|Research Institution||Osaka University|
YASUDA Hideyuki Osaka University, Faculty of Engineering, Associate, 大学院・工学研究科, 助教授 (60239762)
|Project Fiscal Year
1998 – 2001
Completed(Fiscal Year 2002)
|Budget Amount *help
¥53,100,000 (Direct Cost : ¥53,100,000)
Fiscal Year 2001 : ¥9,900,000 (Direct Cost : ¥9,900,000)
Fiscal Year 2000 : ¥7,200,000 (Direct Cost : ¥7,200,000)
Fiscal Year 1999 : ¥8,000,000 (Direct Cost : ¥8,000,000)
Fiscal Year 1998 : ¥28,000,000 (Direct Cost : ¥28,000,000)
|Keywords||High magnetic field / Crystal structure selection / Aligned structure / Structure control / Peritectic reaction / Monotectic reaction / Magnetic alignment / 強磁場 / 結晶組織選択 / 結晶配向 / 組織制御 / 偏晶反応 / 包晶化合物 / 磁場配向|
1.Periodic structure formation during unidirectional solidification
During 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 anisotropy
This 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
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 alloys
There 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 alloys
In 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