中文摘要：

建立了梯度功能材料MIG焊熔积成形制备时磁场环境、焊枪及金属焊样的三维有限元模型.采用Maxwell涡流场及瞬态场对永磁场、交变磁场以及无外加磁场3种MIG焊工艺进行了模拟,并进行了相关实验验证.模拟结果表明,永磁场条件下,熔池受恒定强磁力作用,对熔化金属的搅拌能力弱,无法充分使Al粉和合金钢焊丝融合,不能实现制备梯度功能材料的目的;交变磁场条件下,因熔池受到轴向振荡磁力和横向挤压磁力的共同作用,对熔池的搅拌作用强,有助于梯度功能材料的熔积成形.实验结果与模拟结果符合良好,无磁场条件下,制备出的材料Al含量梯度功能不佳;永磁场条件下,Al粉无法进入焊样中;交变磁场条件下熔积成形的焊样中Al含量呈梯度分布.

英文摘要：

A preparation method of functionally gradient materials（FGM） by metal inert-gas （MIG） welding under magnetic field was proposed in this paper.Three dimensional finite element models of magnetic field,welding gun and metal specimen were built.Maxwell vortex field and instantaneous field were applied to simulate the preparation process with permanent magnetic field, alternating magnetic field and without magnetic field,and the simulation model was verified by the experiment.Simulation and experimental results show that in permanent magnetic field,the stirring of molten pool is weak,the FGM can not be prepared;under alternating magnetic field,the axial oscillating magnetic force and lateral extrusion magnetic force mix round the molten pool effectively, FGM can be prepared by MIG.Without magnetic field,the gradient of Al content in formed FGM is not obvious.Experimental results accord with simulation ones commendably.