摘要
The influence of solidification rate on the microstructure of (Nd,Dy)(12.8)(Fe,Co)(80.7)B-6.5 cast strips was reported in this paper. The strips prepared at different wheel speeds were analyzed by X-ray diffraction (XRD). The microstructure of the strips was investigated by backscattered scanning microscope (BSM). The XRD results show that the strips are mainly composed of the main phase (T-1) existing apparent alignment along [00L]. The thickness of T-1 columnar grains is larger when the solidification rate is lower and the over-small isotropic microcrystalline appear on the cooling surface of the strips when the solidification rate is too high. The adequate wheel speed for obtaining the optimum microstructure of the strips is about V = 2.0 m/s. The strip prepared at V = 2.0 m/s possesses suitable thickness and the highest alignment degree of T-1 columnar grains, uniformly distributed Nd-rich phase, and no existence of alpha-Fe phase. This kind of cast strip is an ideal starting material for preparing sintered magnets with high magnetic properties.
The influence of solidification rate on the microstructure of (Nd,Dy)(12.8)(Fe,Co)(80.7)B-6.5 cast strips was reported in this paper. The strips prepared at different wheel speeds were analyzed by X-ray diffraction (XRD). The microstructure of the strips was investigated by backscattered scanning microscope (BSM). The XRD results show that the strips are mainly composed of the main phase (T-1) existing apparent alignment along [00L]. The thickness of T-1 columnar grains is larger when the solidification rate is lower and the over-small isotropic microcrystalline appear on the cooling surface of the strips when the solidification rate is too high. The adequate wheel speed for obtaining the optimum microstructure of the strips is about V = 2.0 m/s. The strip prepared at V = 2.0 m/s possesses suitable thickness and the highest alignment degree of T-1 columnar grains, uniformly distributed Nd-rich phase, and no existence of alpha-Fe phase. This kind of cast strip is an ideal starting material for preparing sintered magnets with high magnetic properties.
基金
This work was financially supported by the High Technology Research and Development Program of China ("863"program) (No. 2002AA324050 and 2002AA302602) and the National Natural Science Foundation of China (No. 50371046).
