预时效对汽车用2000系铝合金板材性能的影响  

Effect of pre-aging on properties of 2000 series aluminum alloy for automotive body sheets

作　　者：王孟君[1] 任杰[1] 黄电源[1] 姜海涛[1] 

机构地区：[1]中南大学材料科学与工程学院

出　　处：《中南大学学报（自然科学版）》2008年第4期755-759,共5页Journal of Central South University:Science and Technology

基　　金：汽车车身先进设计制造国家重点实验室开放基金资助项目(2005-12)

摘　　要：通过单向拉伸实验、DSC热分析及TEM观察,研究预时效处理对汽车用2036铝合金板材的力学性能、成形性及显微组织的影响。研究结果表明:经180℃/20min的预时效处理后,合金发生软化,合金的屈服强度先降低,之后逐渐回升。在预时效为10min时达到最低值202.3MPa,而此时伸长率和应变硬化指数达到最高,分别为25.5%和0.26,这能有效地改善汽车板材的冲压成形性能;在T4P的预时效初期,GP区发生溶解,形成少量的θ″相核心,抑制随后自然时效的硬化效果;增加预时效时间能使材料产生θ″强化相,而在烤漆过程中形成更多的θ″强化相;与汽车用6000系铝合金相比,2036铝合金的烤漆强化效果较低,冲压前的屈服强度较高,板材的成形难度加大。The effects of pre-aging treatment on the tensile properties, formability and microstructures of 2036 aluminum alloy for automobile body sheets were investigated using the tensile tests, DSC analysis and TEM observation. The results show that the alloy is softened, which is pre-aged at 180 ℃ within 20 min and then natural aging, namely T4P. However, the yield strength decreases first and then rises. The yield strength of the alloy after T4P（10 min） reaches the minimal value 202.3 MPa, but the elongation and strain hardening exponent arrive at the maximum, 25.5% and 0.26 respectively, which can improve its formability effectively. In the early stage of T4P, GP zones dissolve, and generate some θ″ nuclei, so the strengthening effect is restrained during the natural aging following the pre-aging, which causes the decrease of the strength. With the increment of pre-aging time, the θ″ phases are formed. The number of the θ″ phases grows, and the strength increases sharply during the paint-bake treatment. In contrast with the 6000 series aluminum alloy for automobile body sheets, the paint-bake strengthening ability of the 2036 alloy is low and its yield strength before the paint bake is accordingly high, which will add to the difficulty of forming the sheets.

关 键 词：2036铝合金 汽车板 预时效 性能 微观组织 烤漆硬化 

分 类 号：TG146.2[一般工业技术—材料科学与工程]