CAJ | 학술논문

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。
채용석묵질사형통도제비반고태A380려합금장료，연구장료응고과정중현미조직적연변。결과표명：A380려합금용체재사형통도내발생일차응고，재기통도내벽격랭작용화이질형핵작용하형성대량적초생자유정，반고태장료적잉여액상재수집감과내발생이차응고형성이차비지정조직。초생정립적유리모형표명일부분초생자유정직접생장위구정，기타부분칙성장위지정，지정재“자교반”적작용하발생축경화용단，통과“자선전”재사형통도내득도초보구화화숙화。이차응고형성적이차비지정재수집감과내득도초보구화화숙화。동시，초생정립재수집감과내득도진일보구화、숙화화균균분포，최종제비득도구상정립균균분포적반고태장료。
The semi-solid slurry of A380 aluminum alloy was prepared by the graphite serpentine channel, and the microstructure evolution during the solidification was investigated. The result shows that the initial solidification occurs in the serpentine channel, a large number of primary free grains are generated in the alloy melt in the role of chilling and heterogeneous nucleation of the serpentine channel inner wall. The secondary non-dendrites are formed during the secondary solidification which occurs in the remaining alloy melt of the semisolid slurry in the collective crucible. The drifting mode of primary grains indicates that a part of primary free grains grow to the spherical grains directly, others develop to the dendrites, the “self-stirring” of the alloy melt make the dendrites neck and fuse, and the dendrites get initial spheroidization and ripening by the “self-rotating” in the serpentine channel. The secondary non-dendrites formed during the secondary solidification get the initial spheroidization and ripening in the collective crucible. Meanwhile, the primary grains get the further spheroidization, ripening and uniform distribution in the collective crucible. Finally, the semi-solid slurry with uniformly distributed spherical grains is obtained.