Sm3(Fe,Ti)29Nx/α-Fe dual-phase nanometer magnetic material was fabricated through rapid solidification, crystallization and nitridation of Sm-Fe (Ti) alloy. The effect of combination of rapid solidification and Ti alloy addition on the phase for- mation and microstructure of the Sm-Fe alloy is investigated in this paper. The mi- crostructure of amorphous phase and dual-phase nano-grain crystals before and after crystallization annealing were observed using a high-resolution transmission electron microscope (HREM). The dual-phase nano-grains after annealing were compacted together with a clear interface with the direct exchange-coupling mechanism. Different annealing processes were used to examine the melt-spun alloy. Comparison of the images of SEM showed that annealing at 750 ℃ for 10 min was most suitable to get homogeneous and nano-grains. No obvious kink was de- tected in the second quadrant of the hysteresis loop like a single hard magnet, and strong exchange coupling was found between hard magnets and soft magnets.
CUI ChunXiang, ZHANG Ying, SUN JiBing & WANG Ru School of Materials Science and Engineering, Hebei University of Technology, Tianjin 300130, China
In order to increase the modifying effect, the Cu-P master alloy was rapidly solidified with melt-spin method, and the nano-sized ribbon was gained at 105?106 ℃/s. Subsequently, ZL109 alloy was modified by nanocrystal and massive Cu-P master alloy, respectively, with molten metal casting method. The results show that the microscopic structure of ZL109 alloy modified by nanocrystal Cu-P master alloy is better than that modified by massive Cu-P master alloy, the original crystal silicon and eutectic silicon are refined more effectively and the mechanical properties are increased evidently: the tensile-strength is increased by 25%, the elongation is increased by 32.26% and the hardness is increased by 17.2%. Therefore, the melt-spin treatment is a feasible method to improve the modifying effect of Cu-P master alloy.
