( 1. 東北大學 材料與冶金學院，沈陽 110004；
2. 山東輕工業(yè)學院 機電工程學院, 濟南 250100)
摘 要: 通過硬度、 拉伸和成形性實驗及透射電鏡、 掃描電鏡、 能譜和金相分析， 研究了Mg、 Si和Mn含量的變化對6000系汽車板鋁合金的顯微組織、 力學性能及成形性的影響， 并探討適宜的預時效處理工藝。 研究結果表明： 提高合金中的Mn含量， 可增加合金中不可溶結晶相及彌散相粒子的數(shù)量， 前者對合金的延伸率不利， 后者阻礙了合金固溶處理過程中的再結晶。對于Si過剩的合金， 提高合金中Mg和Si的質量比和Mn含量會使其強度升高， 延伸率、 應變硬化指數(shù)、 塑性應變比和埃利克森值被降低。合金板材固溶處理水淬后立即預時效， 較為適宜的預時效（固溶處理后立即在170 ℃下進行5～10 min的短時預時效）不僅能降低其自然時效的硬度， 而且能提高人工時效的硬化效果， 有利于車身構件的沖壓成形和烤漆硬化能力的提高。
關鍵字: 6000系鋁合金； 汽車板； 預時效； 硬度； 烤漆硬化
6000 series aluminium alloys for automotive body sheets
ZUO Liang1
（ 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
