螺旋式环缝电磁搅拌处理对7075合金组织的影响  

Effect of Spiral Annular Electromagnetic Stirring Melt Treatment Technology on Solidification Behavior of 7075 Aluminium Alloy

作　　者：高志华[1] 徐骏[1] 张志峰[1] 刘国钧[1] 李豹[1] 王亚宝[1] 

机构地区：[1]北京有色金属研究总院国家有色金属复合材料工程技术研究中心

出　　处：《特种铸造及有色合金》2015年第1期5-8,共4页Special Casting & Nonferrous Alloys

基　　金：国家重点基础研究发展计划(973计划)资助项目(2011CB606302);国家高技术研究发展计划(863计划)资助项目(2013AA031001);国家国际科技合作计划资助项目(2013DFA51370)

摘　　要：研究了螺旋式环缝电磁搅拌熔体处理技术对7075铝合金凝固行为的影响,分析了不同搅拌电流和浇注温度对合金凝固组织的影响。结果表明,螺旋式环缝电磁搅拌熔体处理技术可以使合金熔体在电磁搅拌条件下受到强剪切处理,剪切速率很大,在整个熔体体积内实现熔体的周向、径向和轴向的运动,最终得到整个熔体体积內均匀分布的温度场和成分场。相比于普通铸造,螺旋电磁搅拌条件下,可以实现7075铝合金的强制均匀凝固,合金凝固显微组织分布均匀细小。随着搅拌电流的增大晶粒组织变得更加细小均匀,当搅拌电流增大到30A时,凝固组织变化不大;随着浇注温度的升高晶粒组织变得粗大、枝晶化,但是相比普通铸造,晶粒组织对浇注温度的依赖性减弱。A new melt processing technology of spiral annular electromagnetic stirring（SA-EMS）was developed for understanding effects on solidification behavior of 7075 aluminium alloy,and effects of stirring current and pouring temperature on microstructures were analyzed.The SA-EMS process innovatively combined non-contact electromagnetic stirring and a spiral annular chamber with specially designed profiles to in-situ make high quality melt slurry,and intensive forced shearing could be achieved under high shears rate and high intensity of turbulence inside the spiral annular chamber.The temperature field,component field and tiny heterogeneous particles are distributed uniformly in the melt.The results indicate that the SA-EMS melt processing technology exhibits desirable grain refinement effects.With the increase of stirring current,the primaryα-Al particles are refined with more spherical.However,with the stirring current of 30 A,the change of solidification structure can be ignored.With the increaseof pouring temperature,the morphology of the primaryα-Al particle by SA-EMS is coarsened from globular to rosette-like and finally to dendritic.However,compared with conventional casting,importance of pouring temperature is weakened.

关 键 词：7075铝合金 螺旋式环缝电磁搅拌 显微组织 

分 类 号：TG146.21[一般工业技术—材料科学与工程] TG249.26[金属学及工艺—金属材料]