Effect Of Crystallization Temperature And Time On Microstructure Of SmFe Alloy

Due to the limitation of the inhomogeneity of the powder structure,there is no efficient method to prepare SmFeN powder with excellent properties.The crystallization of amorphous alloy can effectively control the grain size and improve the uniformity of microstructure.Sm Fe alloy with high amorphous content was prepared by combining the methods of melt-spinning and high energy ball milling,and the influence of different crystallization temperature and time on the microstructure of amorphous Sm Fe alloy was studied to prepare the fine and uniform microstructure.The influence of the uniformity of the microstructure on the nitrogen content and the effect of amorphous microstructure on the nitrogen content in the alloy were studied.Through the hot state experiment of Sm Fe alloy,the amorphous ribbons were prepared of by melt-spinning.When the rotating speed of copper roller is 35 m/s,the cooling speed of solution is 1.03×10⁶ K/s,and the content of amorphous is more than 80% after ball milling.When Zr and Nb are added during smelting,the content of amorphous in the ribbons increases by 30% after melt-spinning,and the content of amorphous microstructure is more than 85% after milled for 2 h.According to the results of DTA,the crystallization kinetics of the amorphous milled is calculated.It is found that the nucleation is more difficult than the growth of grain in the crystallization process of the amorphous Sm Fe alloy.The Sm₂Fe₁₇（24 wt.%）ribbons are crystallized at 660 ℃ for 15 minutes,the powders milled for 2.5 h are crystallized at 700 ℃ for 20 minutes and the powders milled for 2 h are crystallized at 700 ℃ for 25 minutes are the optimal parameters in crystallization process.Nitriding results show that the nitrogen content of Sm₂Fe₁₇ ZrNb_0.4 powders milled for 2 h is 2.57%,which is about 0.16% higher than that of Sm₂Fe₁₇ powders milled for 2.5 h,and 0.59% higher than that of the melt-spun ribbons.When the amorphous alloy is nitrided directly,the higher the amorphous content is,the more the nitrogen content will be infiltrated.The nitrogen content of the alloy after crystallization at low temperature for a long time will decrease by 0.86%.Figure 51;Table 13;Reference 82...