( 1. 东北大学 材料与冶金学院，沈阳 110004；
2. 山东轻工业学院 机电工程学院, 济南 250100)
摘 要: 通过硬度、 拉伸和成形性实验及透射电镜、 扫描电镜、 能谱和金相分析， 研究了Mg、 Si和Mn含量的变化对6000系汽车板铝合金的显微组织、 力学性能及成形性的影响， 并探讨适宜的预时效处理工艺。 研究结果表明： 提高合金中的Mn含量， 可增加合金中不可溶结晶相及弥散相粒子的数量， 前者对合金的延伸率不利， 后者阻碍了合金固溶处理过程中的再结晶。对于Si过剩的合金， 提高合金中Mg和Si的质量比和Mn含量会使其强度升高， 延伸率、 应变硬化指数、 塑性应变比和埃利克森值被降低。合金板材固溶处理水淬后立即预时效， 较为适宜的预时效（固溶处理后立即在170 ℃下进行5～10 min的短时预时效）不仅能降低其自然时效的硬度， 而且能提高人工时效的硬化效果， 有利于车身构件的冲压成形和烤漆硬化能力的提高。
关键字: 6000系铝合金； 汽车板； 预时效； 硬度； 烤漆硬化
6000 series aluminium alloys for automotive body sheets
（ 1. School of Materials and Metallurgy,
Northeastern University, Shenyang 110004, China;
2. School of Mechanical and Electrical Engineering,
Shandong Institute of Light Industry, Jinan 250100, China）
Abstract: Through transmission electron microscope, scan electron microscope, energy spectrum, metallograph analysis and hardness, tensile and formability tests, the effects of Mg, Si and Mn contents variation on the microstructures, tensile properties and formability of a few 6000 series aluminium alloys for automobile body sheets were investigated, the suitable pre-aging treatment technology was also researched. The results show that the number of insoluble constituents and dispersoid particles in alloys increase with increase of Mn content, the former is detrimental for the specific elongation of alloys, and the latter impedes recrystallization during solution treatment. For Si alloys excess, the strength is enhanced, and the specific elongation, strain hardening exponent, plastic strain ratio and Erichsen value, are decreased with Mg and Si mass ratio and Mn content increasing. Pre-aging of alloy sheets immediately after solution treatment and quenching can not only reduce the hardness of subsequently natural aging, but also enhance the hardening effect of following artificial aging, which is advantage to stampping formation and hardenability increasing during paint bake cycle. The suitable pre-aging treatment system is the short-time pre-aging at 170 ℃ for 5-10 min immediately after solution treatment.
Key words: 6000 series aluminium alloys; automotive body sheets; pre-aging; hardness; paint bake hardenability
