摘要
The extrusion preform of the spray-formed5A12Al alloy was hot rolled using high reduction rolling technology.By means of transmission electron microscopy(TEM),electron backscatter diffraction(EBSD)and energy dispersive spectroscopy(EDS),the microstructure evolution was studied and the strengthening and toughening mechanism was thereby proposed.The results indicate that discontinuous and continuous dynamic recrystallization occurred during the hot rolling deformation of the spray-formed5A12Al alloy.The grain size was significantly refined and the micro-scale grains formed.Partial dynamic recrystallization leads to a significant increase of dislocation density and cellular structure.The Mg atoms were distributed in the Al matrix mainly in the presence of solid solution rather than the formation of precipitate.High solid solution of Mg atoms not only hindered the dislocation motion and increased the density of dislocation,but also exhibited a remarkable solid solution strengthening effect,which contributes to the high strength and high toughness of the as-rolled sheets.The tensile strength and elongation of spray formed5A12Al alloy at room temperature after3passes hot rolling were622MPa and20%,respectively.
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%。
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
作者简介
Corresponding author: Cai-he FAN; Tel: +86-731-22183432; E-mail: 369581813@qq.com
