Nd-Fe-B铸锭的晶体生长特征

CRYSTAL GROWTH FEATURES OF Nd-Fe-B INGOT

ＳＥＭ， ＸＲＤ以及磁畴观察表明： Ｎｄ－Ｆｅ－Ｂ铸锭中 Ｎｄ２Ｆｅ１４Ｂ相以片状晶方式生长，若干个彼此近似平行排列的片状晶组成一个片状晶团，不同片状晶团之间沿易磁化轴有约 ９０°位向差，这种生长特征与 Ｎｄ２Ｆｅ１４Ｂ相的晶体结构特征有关经退火后，片状晶消失，晶粒等轴化，原始片状晶团之间的位向差在退火后大幅度减小． Ｘ射线衍射表明， Ｎｄ－Ｆｅ－Ｂ铸锭中

The crystal growth features of Nd-Fe-Bingot are studied by SEM, XRD and magnetic domain observation. It is noticed that the growth of the Nd2Fe14B grains during solidification is insheet-like pattern, and a number of these sheet-like grains constitute a sheet--like grain group. There exist about 90 degrees phase difference around the c--axis between the adjacent sheet--like grain groups. Such a crystal growth pattern of Nd-Fe-Bingots has relevance to the crystallographic features of Nd2Fe14B.After annealing, the sheet--like grains are tended to be equiaxial and the grain size is apparently coarsened.Meanwhile, the phase difference between the adjacent heet-like grain groups is decreased significantly,which suggests that the ingot grains grow with a feature of preferred orientation during annealing.