强磁场对Cu-80%Pb过偏晶合金中富Cu颗粒迁移行为的影响

来源期刊：金属学报2010年第4期

论文作者：张林 王恩刚 左小伟 赫冀成

文章页码：423 - 428

关键词：Cu-Pb合金； 偏晶合金； 颗粒迁移； 强磁场

Key words：Cu-Pb alloy； monotectic alloy； particle transition； high magnetic field

摘    要：将含有大量富Cu颗粒的Cu-80%Pb(质量分数)过偏晶合金在强磁场作用下进行不同温度的保温实验,研究了富Cu颗粒在液固混合区的迁移行为.结果表明,无磁场作用时,富Cu颗粒在800℃以上出现迁移而上浮,900℃以上在试样顶部形成致密的富Cu分层,颗粒尺寸及迁移速率随温度升高而增加;富Cu颗粒在迁移过程中可通过热化长大或合并,其机制与富Cu液滴不同;富Cu颗粒群整体向上迁移,颗粒区与枝晶区有明显边界,颗粒间相互作用可使其迁移速率降低.强磁场具有降低颗粒迁移速度,抑制颗粒熟化及合并的作用,降低了富Cu颗粒的偏析程度,抑制致密富Cu分层的形成.考虑颗粒间相互作用,对有无磁场作用下颗粒所受的作用力和运动终端速度进行了分析和计算.

Abstract: The Cu-80%Pb(mass fraction) hypermonotectic alloy with a dense distribution of Cu-rich particles was annealed at different temperatures under high magnetic field,the transition behavior of Cu-rich particles in solid-liquid mixture zone was investigated.The results show that,the transition behavior of Cu-rich particles occurs above 800℃,a compact segregation layer forms in the sample top above 900℃,the particle size and transition velocity increase with annealing temperature increasing. The Cu-rich particles grow and coalesce with each other during transiting,the coalescence mechanism is different from Cu-rich droplets.The cluster of Cu-rich particles float up wholly,leave a clear boundary between Cu-rich particle and Cu-rich dendrite zones,the mutual interaction between the particles makes the transition velocity decreased.The high magnetic field has effect on decreasing the transition velocity of Cu-rich particles,inhibiting the coarsening and coalescing of Cu-rich particles, which could decrease the segregation of Cu-rich particles,and inhibit the formation of compact Cu-rich segregation layers.Based on the mutual interaction between the particles,the acting forces on the Cu-rich particles and the final velocity have been analyzed and calculated to show the influence of magnetic field.