大压下量轧制喷射成形5A12铝合金的显微组织演变及强化机制（英文）

发布时间：2019-05-10 06:29

【摘要】：基于大压下量轧制工艺对喷射成形5A12铝合金挤压坯进行热轧变形,采用透射电镜(TEM)、电子背散射衍射技术(EBSD)和能谱(EDS)分析合金显微组织的演变规律,进而探讨合金的强韧化机理。研究结果表明:喷射成形5A12铝合金在热轧变形过程中,发生了不连续动态再结晶和连续动态再结晶,晶粒组织显著细化,形成了亚微米级组织结构;同时,不完全动态再结晶导致合金的位错密度显著增加和胞状组织大量形成。喷射成形工艺实现了5A12铝合金中Mg原子完全固溶,并在热变形过程中保留下来,而未生成沉淀相析出。均匀分布在铝基体中的过饱和Mg原子与位错发生交互作用,阻碍了位错运动,提高了位错密度,因而固溶强化效果显著,是合金获得高强高韧性能的最根本原因。喷射成形5A12铝合金经3道次热轧变形后的室温拉伸强度和伸长率分别达到622 MPa和20%。
[Abstract]:Based on the high reduction rolling process, the hot rolling deformation of spray formed 5A12 aluminum alloy extrusion billet was carried out. The microstructure evolution of the alloy was analyzed by transmission electron microscope (TEM),) electron backscattering diffraction (EBSD) and energy spectrum (EDS) (EDS). Furthermore, the strengthening and toughness mechanism of the alloy is discussed. The results show that during hot rolling deformation of spray formed 5A12 aluminum alloy, discrete dynamic recrystallizing and continuous dynamic recrystallizing occur, the grain structure is significantly refined, and the submicron microstructure is formed. At the same time, incomplete dynamic recrystallization resulted in a significant increase in dislocation density and a large number of cellular structures. The spray forming process realized the complete solid solution of Mg atom in 5A12 aluminum alloy and retained it in the process of thermal deformation without precipitating phase precipitation. The interaction between supersatured Mg atoms uniformly distributed in aluminum matrix and dislocation hinders the dislocation movement and increases the dislocation density. Therefore, the solid solution strengthening effect is remarkable, which is the most fundamental reason for the alloy to obtain high strength and high toughness. The room temperature tensile strength and elongation of spray formed 5A12 aluminum alloy after 3-pass hot rolling reached 622 MPa and 20%, respectively.
【作者单位】：湖南工业大学冶金与材料工程学院;中国中车株洲电力机车有限公司;
【基金】：Project(2017JJ2073) supported by the Natural Science Foundation of Hunan Province,China Project(15B063) supported by the Youth Research Foundation of Education Bureau of Hunan Province,China
【分类号】：TG146.21;TG339

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