电磁搅拌下混合稀土对半固态A356合金初生α相的细化机理  

Refinement mechanism of mixed rare earth on primary α phase in semisolid A356 alloy under electromagnetic stirring

作　　者：刘政[1] 许鹤君[2] 罗浩林[2] 周志鹏[2] 谌庆春[2] 

机构地区：[1]江西理工大学机电工程学院,赣州341000 [2]江西理工大学材料科学与工程学院,赣州341000

出　　处：《中国有色金属学报》2013年第8期2110-2117,共8页The Chinese Journal of Nonferrous Metals

基　　金：国家自然科学基金资助项目(51144009,51361012);江西省自然科学基金资助项目(20114bab206014);江西省教育厅科技落地计划项目(KJLD12070)

摘　　要：为获得细小、圆整且分布均匀的半固态A356合金初生α相,向合金熔体中添加了不同含量的混合稀土La和Ce对合金进行变质处理,熔体经620℃浇注后,利用变频控制的电磁搅拌装置对熔体进行电磁搅拌15 s并使其在610℃保温10 min,观察并分析合金凝固组织中初生α相的形貌与尺寸。利用扫描电镜和能谱仪分析测定La和Ce在基体的分布情况,探讨混合稀土元素在电磁搅拌条件下对初生α相的细化机制。结果表明:La和Ce在电磁搅拌条件下易于均匀分布在初生α相周围,混合稀土元素La与Ce在短时弱电磁搅拌的条件下可以高效地细化半固态A356合金组织,稀土对半固态A356铝合金的初生α相细化机制与稀土在铝合金中产生的共晶反应有关。In order to obtain the fine, round and uniform distribution primary α phase in semisolid A356 alloy, the different amounts of mixed RE elements La and Ce were added into the alloy melt,and the melt was poured at 620℃and slightly electromagnetically stirred for 15 s with an electromagnetic stirrer controlled by frequency conversion, then, it was isothermally held at 615℃for 10 min. The morphology and size of the primaryαphase were analyzed, and the distributions of La and Ce were researched by SEM and EDS. The refinement mechanism of mixed RE under electromagnetic stirring was discussed. The results indicate that RE elements La and Ce are easy to uniformly distribute around the primaryαphase under electromagnetic stirring, and RE elements La and Ce can effectively refine the primaryαphase under the condition of short and weak electromagnetic stirring. The refining mechanism of RE on the primaryαphase in semisolid A356 alloy can be concerned with the eutectic reaction induced by RE in the alloy.

关 键 词：混合稀土 半固态A356合金 电磁搅拌 初生Α相 共晶反应 

分 类 号：TG146[一般工业技术—材料科学与工程] TG244[金属学及工艺—金属材料]