定向凝固条件下Nd_2Fe_(14)B枝晶的择优生长方向

PREFERRED GROWTH DIRECTION OF Nd_2Fe_14B DENDRITE IN DIRECTIONAL SOLIDIFICATION

定向凝固技术已经成功地应用于可加工S_m-C_o永磁体的制备并表现出工艺简单等优点。该技术中,易磁化轴的取向排列是利用基体相定向凝固形成的择优取向来实现的。这就要求基体相的择优生长方向必须与其易磁化方向平行;这是采用定向凝固技术制备永磁体的前提。对于NdFeB永磁合金,基体相Nd_2Fe_(14)B具有四方晶体结构。

Directional solidification process of Nd17Fe75B8alloy is studied experimentally. It is found that the Nd2Fe14B matrix crystallized directly from the melt and grows directlynally in dendrite formation. The preferred growth direction of the dendrite is [100], perpendicular to its easy magnetication direction [001].