半固态A380铝合金浆料凝固过程中显微组织的演变

发布时间：2018-03-07 19:09

本文选题：A铝合金　切入点：半固态浆料　出处：《中国有色金属学报》2015年05期 　论文类型：期刊论文

【摘要】：采用石墨质蛇形通道制备半固态A380铝合金浆料,研究浆料凝固过程中显微组织的演变。结果表明:A380铝合金熔体在蛇形通道内发生一次凝固,在其通道内壁激冷作用和异质形核作用下形成大量的初生自由晶,半固态浆料的剩余液相在收集坩埚内发生二次凝固形成二次非枝晶组织。初生晶粒的游离模型表明一部分初生自由晶直接生长为球晶,其他部分则成长为枝晶,枝晶在"自搅拌"的作用下发生缩颈和熔断,通过"自旋转"在蛇形通道内得到初步球化和熟化。二次凝固形成的二次非枝晶在收集坩埚内得到初步球化和熟化。同时,初生晶粒在收集坩埚内得到进一步球化、熟化和均匀分布,最终制备得到球状晶粒均匀分布的半固态浆料。
[Abstract]:The semi-solid A380 aluminum alloy slurry was prepared by graphite serpentine channel. The microstructure evolution of the slurry during solidification was studied. The results showed that the melt of 1: A380 aluminum alloy solidified once in the serpentine channel. A large number of primary free crystals were formed by the cooling of the inner wall of the channel and the heterogeneous nucleation. Secondary solidification of residual liquid phase of semi-solid slurry formed secondary non-dendritic structure in a collection crucible. The free model of primary grains shows that some primary free crystals grow directly into spherulites and others grow into dendrites. Necking and melting of dendrites occur under the action of "self-stirring", and primary spheroidization and ripening of dendrites are obtained in serpentine channels by "self-rotation". Secondary non-dendrites formed by secondary solidification are spheroidized and matured in collecting crucible. The primary grains were further spheroidized, matured and uniformly distributed in the collecting crucible. Finally, the semi-solid slurry with uniform distribution of spherical grains was prepared.
【作者单位】：北京科技大学材料科学与工程学院;
【基金】：国家重点基础研究发展计划资助项目(2011CB606300) 国家自然科学基金资助项目(50774007)
【分类号】：TG146.21

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