中文摘要：

抑制凝固过程中熔体内部的湍流是获得沿易轴取向晶体组织的关键。在凝固过程中，熔体内部的对流状态主要受冷却速率影响，修正的瑞利数被用来描述不同冷却速率下的熔体湍流程度。当反映熔体紊乱程度的瑞利数小于磁场作用下的临界瑞利数时，熔体的内部扰动被磁场抑制，生长中的晶体将克服热无序作用平行于磁场沿易磁化轴取向。修正的瑞利数和临界瑞利数接近时的凝固和磁场参数可作为磁性材料晶体生长取向控制的临界条件。

英文摘要：

The critical conditions of solidification orientation for Solidification of giant magnetostrictive materials R-Fe alloy in a magnetic field have been investigated. The experiment results show that suppressing the turbulence in melt is a key factor in texturing the magnetic materials. In solidification course, the turbulent degree in melt is dominated by the cooling rate, and a modified Ra^m number is used to simulate the state of turbulence at various cooling rates. While the value of the critical Ra^c number in magnetic field is large than that of the modified Ra^m number in melt, the temperature oscillations in melt will be restrained, and the texture along the easy magnetic axis will be dominant in the sample. Therefore the critical conditions of effective orienting action for magnetic materials by solidification in a magnetic field can be definite as the rate of the critical Ra^c number in a magnetic field to Ra^m number in melt is close to 1.