磁声波对金属凝固组织的影响

提出了运用强磁场和交流电流的共同作用直接在金属液中产生声波（磁声波）的新方法，并研究了所生成的磁声波在细化合金凝固组织晶粒的效果，该方法可以从根本上解决机械声波无法在高温生产领域应用的难题，理论解析表明，运用交变电磁力在液体金属内生成的磁声波的强度和所施加的静磁场的磁感应强度和交流电流的电流密度的乘积成正比；电磁力的频率越大，生成的磁声波越接近于由机械振动产生的声波，实验中测定的磁声波压力和理论解析结果基本一致，这种方法产生的磁声波具有促进金属凝固组织晶粒细化的作用。

EFFECT OF MAGNETO-ACOUSTIC WAVES ON SOLIDI FICATION STRUCTURES OF METAL

The simultaneous imposition of a high static magnetic field and an alternating electrical current was utilized to excite acoustic waves (magneto-acoustic waves) directly in a liquid metal instead of conventional mechanical vibration method. The effect of the generated waves on solidification structures was also examined. The theoretical analysis shows that the intensity of the generated waves is in proportion to the product of the imposed static magnetic field and alternating electrical current. And when the frequency of imposed alternating electromagnetic force increased, the characteristic of the generated waves becomes more similar to that of those excited by mechanical vibration. Pressure perturbations detected experimentally in liquid gallium appropriately agreed with the theoretical predictions. The generated magneto-acoustic waves improved solidified structures of Sn-Pb alloys. This study indicates a new method to generate acoustic waves by imposing alternating electromagnetic force locally on a metal, which can overcome the difficulties happened when the waves excited by mechanical vibration applied in high temperature environment.