论文部分内容阅读
采用快淬法制备SmFe合金的过程中,在不同快淬速率下会得到4种不同外部形貌的合金,采用XRD,SEM,EDS等方法分析不同快淬速率下SmFe合金的相组成及显微组织结构,研究快淬速率及Sm含量对快淬态合金薄带相组成和显微组织结构的影响。研究表明:随着快淬速率的升高,冷却速度及过冷度也随之升高,合金薄带的相组成与组织形貌发生较大的改变,当快淬速率达到15 m·s-1时,SmFe合金的相结构开始由Th2Zn17型晶体结构转变为TbCu7型结构,通过对不同快淬速率下获得的合金薄带进行SEM和EDS分析,确定快淬态的SmFe合金薄带均由α-Fe枝晶相、包晶SmFe相及富Sm相组成,并且随着快淬速率的升高,枝晶逐渐向等轴晶转变,晶粒得到一定程度的细化,当快淬速率达到40 m·s-1时,枝晶生长转变为球状晶生长,晶粒大幅度细化,同时偏析现象消失,组织分布均匀化;通过对在同一快淬速率下获得的不同Sm含量的快淬SmFe合金薄带进行XRD分析,发现Sm含量的降低有利于TbCu7型结构的SmFe合金的获得,经SEM与EDS分析,发现随着Sm含量的增多,合金组织中α-Fe枝晶相逐渐减少,富Sm相逐渐增多。
In the process of preparing SmFe alloy by rapid quenching, four different morphologies of alloy were obtained at different quenching rates. The phase composition and microstructure of SmFe alloy at different quenching rates were analyzed by XRD, SEM and EDS The structure and microstructure of the rapidly quenched ribbons were investigated by the influence of the rapid quenching rate and Sm content. The results show that as the quenching rate increases, the cooling rate and undercooling also increase, and the phase composition and microstructure of the alloy strip change greatly. When the quenching rate reaches 15 m · s- 1, the phase structure of the SmFe alloy begins to change from the Th2Zn17 crystal structure to the TbCu7 structure. SEM and EDS analysis of the alloy ribbons obtained at different quenching rates show that the SmFe alloy ribbons in the quenched state are dominated by α -Fe dendrite phase, perovskite SmFe phase and Sm-rich phase. With the increase of quenching rate, the dendrites gradually transformed into equiaxed grains and the grains were refined to a certain degree. When the quenching rate reached 40 m · s-1, the growth of dendrite transformed into spherulitic growth, and the grain size was greatly refined. At the same time, the segregation phenomenon disappeared and the microstructure was homogenized. Through the comparison of the quenching properties of SmFe The XRD analysis showed that the decrease of Sm content was beneficial to the obtaining of SmFe alloy with TbCu7 structure. The SEM and EDS analysis showed that with the increase of Sm content, the amount of α-Fe dendrite phase decreased, Sm phase gradually increased.