Al-Mg-Si合金双辊铸轧板坯不同位置处微观组织差异及其对板坯性能的影响  

Microstructural differences at different positions of Al-Mg-Si alloy twin-rolling casting plate and effects on plate properties

作　　者：王旭成 黄元春 WANG Xucheng;HUANG Yuanchun(College of Mechanical and Electrical Engineering,Central South University,Changsha 410083,China;Light Alloy Research Institute,Central South University,Changsha 410083,China)

机构地区：[1]中南大学机电工程学院,长沙410083 [2]中南大学轻合金研究院,长沙410083

出　　处：《材料工程》2024年第7期130-139,共10页Journal of Materials Engineering

基　　金：国家自然科学基金项目(51575539)。

摘　　要：传统的热轧法生产Al-Mg-Si合金板材存在工序多、时间长和成本高等缺点,严重制约了Al-Mg-Si合金的发展,因此,近年来采用双辊铸轧工艺生产Al-Mg-Si合金板材获得了极大的关注。本工作采用双辊铸轧工艺制备Al-Mg-Si铝合金铸轧板坯,探究板坯不同位置的微观组织差异及其对板坯性能的影响,结果表明:板坯边部和心部的晶粒形貌差异明显,织构组成复杂,大量第二相沿晶界处不均匀分布,板坯内部存在明显的元素偏析。通过理论计算,铸轧板坯边部的织构强化贡献强度为10.7 MPa,晶界强化贡献强度为86.8 MPa,而铸轧板坯心部的织构强化贡献强度为15.1 MPa,晶界强化贡献强度为82.4 MPa,板织构和随机织构对于铸轧板坯的强度贡献有限,边部和心部的强度差异主要取决于晶界强化。板坯边部和心部存在不同程度的位错缠结,边部的位错密度高于心部,这与小角度晶界统计结果相一致。针对板坯组织不均匀性的特点,通过热力学计算,为板坯后续热处理制度提供了理论指导。The Al-Mg-Si alloy plate produced by traditional hot rolling has many defects such as complicated processes,long time and high cost,which seriously restricts the development of Al-Mg-Si alloy.Therefore,the Al-Mg-Si alloy plate produced by the twin-rolling casting process has attracted great attention in recent years.The twin-rolling casting process was used to prepare the Al-Mg-Si aluminum alloy plate,and the difference of microstructure at different positions of the plate and the influence on the performance were investigated.The results show that the grain morphology of the edge and the center of the plate is significantly different,the texture composition is complex,a large number of second phases are unevenly distributed along the grain boundary,and there is obvious element segregation inside the plate.According to the theoretical calculation,the contribution strength of texture strengthening at the edges of the twin-rolling casting plate is 10.7 MPa and the contribution strength of grain boundary strengthening is 86.8 MPa,while the contribution strength of texture strengthening in the center of the twin-rolling casting plate is 15.1 MPa and the contribution strength of grain boundary strengthening is 82.4 MPa.The contribution of plate texture and random texture to the strength is limited,and the strength difference between edge and center mainly depends on the grain boundary strengthening.Different degrees of dislocation tangles exist at the edge and the center,and the dislocation density at the edge is higher than that at the center,which is consistent with the statistical results of low angle grain boundaries.According to the characteristics of microstructure inhomogeneity of the plate,the theoretical guidance for the subsequent heat treatment system of the plate is provided through thermodynamic calculation.

关 键 词：AL-MG-SI合金 双辊铸轧 微观表征 晶界强化 热力学计算 

分 类 号：TG166.3[金属学及工艺—热处理]