强磁场下金属熔体中颗粒运动的行为研究

Study On the Motion of Particles in the Metal Melt under High Magnetic Field

将Al-5Ti-1B中间合金在有无磁场的条件下进行重熔凝固实验,对凝固后的样品金相组织进行了观察.分析了其中未熔化的固相颗粒在组织中的分布和排列状况,结果表明:与不施加磁场时的样品中针状的TiAl3颗粒杂乱无章排列相比,10 T强磁场下的样品中呈长轴平行于外场方向排列;同时,重力引起的颗粒沉降行为明显较无磁场时的要弱.说明强磁场对金属熔体中固相颗粒迁移和旋转的行为有重要影响:针状的弱磁性颗粒在形状各向异性的影响下发生了磁致旋转,使之平行于外场排列;而施加强磁场后熔体的表征黏度系数增大抑制了颗粒的沉降行为.因此,可通过改变磁场参数控制凝固组织中强化相的分布和排列,制备性能优良的金属基颗粒复合材料.

The experiments of re-meh and solidification of Al-5Ti-1 B master alloy are carried out with and without imposition of high magnetic field up to 10 T, and the solidified structure are observed by using optical and SEM. The distribution and alignment of un-meh solid particles in microstrncture are studied. The results show that TiAl3 particles are aligned parallel to the external field under a 10 T, compared with distributed random alignment. And the deposition of TiAl3 particles is damped which is resulted from the increasing of effective viscosity. So, the high performance metal matrix composites can be manufactured by using high magnetic rotation.