Abstract

The formation of the microstructure in the rheo-diecastings were studied by the experiment of rheo-diecasting with semi-solid A380 Aluminum alloy slurry. The results show that the grain diameter and shape factor of primary α-Al grains decreased and increased along the rheo-diecasting direction, respectively, making the primary α-Al grains gradually distributing uniformly. The combination of injection pressure and narrow gate of the runner and ingate was the main reason for the evolution of the primary α-Al grains, moreover, the collision and friction among primary α-Al grains during the filling were helpful for the refinement and spheroidization of the primary α-Al grains. The residual liquid solidified into the secondary solidification microstructure accompanied by the evolution of the primary α-Al grains. The accumulation of the fragments of the primary α-Al grains, the secondary α₂-Al nuclei or grains which formed in previous positions, the effective nucleation rate of the residual liquid, and the collision and fraction among the secondary α₂-Al grains and between the secondary α₂-Al grain and the primary α-Al grains made the secondary solidification microstructure of the residual liquid present multiplex and complicate characteristics.

Graphic Abstract

In this paper, the formation of the microstructure in the rheo-diecastings were studied by the experiment of rheo-diecasting. During the rheo-diecasting, the grain diameter and shape factor of primary α-Al grains decreased and increased, respectively along the rheo-diecasting direction, which made the primary α-Al grains gradually distribute uniformly. The drifting of the fragments of the primary α-Al grains and secondary α2-Al nucleus, and the effective nucleation rate of the residual liquid played an important effect on the morphology of the secondary solidification structure.

中文翻译：

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半固态A380铝合金浆料流变压铸的微观组织形成研究

摘要

通过半固态A380铝合金浆料的流变压铸实验，研究了流变压铸的显微组织形成。结果表明，初生α-Al晶粒的粒径和形状因子分别沿流变压铸方向减小和增大，从而使初生α-Al晶粒逐渐均匀地分布。注入压力与流道和门的狭窄浇口的结合是原生α-Al晶粒演化的主要原因，此外，填充过程中原生α-Al晶粒之间的碰撞和摩擦有助于细化和球化α-Al晶粒的数量。残留的液体凝固成二次凝固的微观结构，并伴随着初生α-Al晶粒的析出。_2种，其形成在先前位置-Al核或颗粒，残留液体的有效成核速率，二次α之间的碰撞和馏分₂ -Al晶粒二次α和之间₂ -Al晶粒和主的α-Al晶粒使残余液体的二次凝固微观结构呈现多重和复杂的特性。

图形摘要

本文通过流变压铸的实验研究了流变压铸的微观结构的形成。在流变压铸过程中，初生α-Al晶粒的直径和形状因子分别沿流变压铸方向减小和增加，从而使初生α-Al晶粒逐渐均匀地分布。一次α-Al晶粒和二次α2-Al核碎片的漂移以及残余液体的有效成核速率对二次凝固组织的形态起着重要作用。