TbDyFe合金定向凝固过程中晶体的取向生长

Oriented Growth of Terfenol-D Crystal during the Directional Solidification of TbDyFe Alloy

利用自制的超高温度梯度定向凝固装置 ZMLMC,在不用籽晶的情况下 ,制备出了完全〈1 1 0〉取向的 7 mm× 1 2 0 mm的稀土超磁致伸缩棒材 ,并对定向凝固开始到晶体稳定生长全过程晶体生长的形貌进行了观察和分析 .结果表明 ,晶体的取向程度和其生长形貌有明显的对应关系 ;在温度梯度为 70 0 K/cm,抽拉速率为 6～ 1 0 μm/s的条件下 ,Tb0 .2 7Dy0 .73 Fe1.9合金棒材定向凝固长度达 1 2 mm时 ,就可获得〈1 1 0〉取向的晶体 ,而该晶体达到稳定生长所需的棒材长度至少为 2 0 mm;所制棒材中〈1 1 0〉取向生长方向与其轴向间的偏差仅为

Under no crystal seeds, 7 mm×120 mm rare earth giant magnetostrictive rods with precise 〈110〉 orientation were manufactured in a super high temperature gradient directional solidification equipment (ZMLMC). Morphologies of the crystal from the beginning of solidification to the stable growth of Terfenol\|D crystal were examined and analyzed. The results indicate that during the directional solidification process of Tb 0.27 Dy 0.73 Fe 1.9 alloy(Terfenol\|D) there exists a certain relationship between the crystal growth morphology and the crystal orientation degree. Under the condition of the temperature gradient of 700 K/cm and the withdraw velocity of 6～10 μm/s, Tb 0.27 Dy 0.73 Fe 1.9 rod with 〈110〉 oriented crystals can be obtained as the solidified length arrives 12 mm. The length of the solidified rod is at least 20 mm, the 〈110〉 oriented crystals can grow steadily. A deviation only 3° is existed between the growth direction of Terfenol\|D crystal and the rod axis.