64th Magnetic Materials Center Seminar
December 3, 2007, 15:30-
8th floor middle seminar room, Sengen
Properties of Co2MnAlxSi1-x
K. Kodama
Co2MnAl and Co2MnSi are candidate for half metals. But, these do not show the 100% spin polarization. I observed influence of substitution Al for Si.

Effect of Solute additions on the hardening response of Mg-2.4Zn alloys
C. Mendis
Addition of solid solution strengthening element can further improve the maximum hardness achieved or the kinetics of precipitation hardening. In an attempt to further refine the microstructure and improve the strength of Mg-2.4Zn alloys different solute additions may be added. In this presentation, I will discuss the effect of Sn and Al additions on the age hardening of Mg-2.4Zn alloy and Mg-2.4Zn-0.1Ag-0.1Ca alloys at 160oC.
Following this, some on going work on characterization of precipitates observed in extruded Mg-2.4Zn-0.1Ag-0.1Ca-0.2Zr will be briefly discussed.

SEM-FIB/TEM/3DAP multiscale structure analysis of sintered Nd-Fe-B magnet
T. Ohkubo and W.F. Li
There are many reports about structure of sintered NdFeB magnet. However the relation between the structure and magnetic property is not completely understood. In order to understand the relation, we need to analyze the structure from micrometer scale to atomic scale. In this study, we applied multi-scale analysis techniques such as SEM-FIB, TEM and 3DAP to see the structural difference between Cu free and Cu contain NdFeB specimens. The (BH)max of Cu contain specimen shows almost 4 times larger than that of Cu free specimen. From SEM-FIB in-situ observation, in the case of Cu contain specimen, it was confirmed that all grain boundaries were covered by Nd-rich phase. Also, from TEM observation, the crystal structure near grain boundary phase was more complete which means the reduction of magnetic anisotropy is small. Furthermore, the exchange coupling was decoupled by amorphous Nd-rich phase. As these results, Hc is increased. From 3DAP analysis, it was found that Cu was enriched in Nd-rich phase, and interface between Nd-rich phase and Nd2Fe14B phase.