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采用电磁搅拌法制备了Al-4Cu合金坯锭,对合金坯锭进行了二次加热重熔试验,分别研究了铸态、电磁搅拌态、二次加热重熔态合金中Cu元素的分布规律。结果表明,采用电磁搅拌方法制备的半固态坯锭存在Cu元素在晶界处富集现象,多晶交汇处富集最明显,晶粒内析出的含Cu金属间化合物数量少于未搅拌的;电磁搅拌强度越大,Cu元素在晶界处富集程度越明显;圆柱形坯锭沿径向由表面向心部的Cu元素富集程度逐渐增大。二次加热重熔改变了Cu元素在坯锭的分布,Cu元素分布与二次加热重熔的液相数量有关;重熔的液相数量较少时,Cu元素仍然在未重熔的固相之间富集,而重熔区内的Cu元素趋于均匀分布;重熔和未重熔区出现Cu元素平均含量的差值。
The Al-4Cu alloy billets were prepared by electromagnetic stirring method and the second heating remelting test was carried out on the alloy billets. The distribution of Cu elements in as-cast, electromagnetized and reheated alloys was studied respectively. The results show that the semi - solid billets prepared by electromagnetic stirring have the enrichment of Cu at the grain boundaries, the most abundant polycrystalline junctions and the less Cu - containing intermetallic compounds precipitated in the grains. The greater the intensity of electromagnetic stirring, the more obvious the enrichment of Cu element at the grain boundaries. The enrichment of Cu element along the radial direction from the surface to the center of the cylindrical billet gradually increases. The second heating remelting changed the distribution of Cu element in the billet. The distribution of Cu element was related to the amount of liquid phase remelted by reheating. When the amount of remelting liquid phase was small, the Cu element was still in the remelted solid phase While the Cu elements in the remelting zone tend to be evenly distributed. The difference of the average content of Cu elements in remelting and non-remelting zones appears.