Cu含量对Al-1.0Mg-1.0Si-0.6Mn薄板成形性及烤漆硬化性的影响

采用拉伸、杯突实验结合DSC分析系统研究了Cu含量对汽车车身用Al-1.0Mg-1.0Si-（0.1-0.7）Cu-0.6Mn合金T4态薄板各类成形性指标及模拟烤漆处理后性能变化的影响规律.结果表明：随着Cu含量增加,T4态合金板材的强度单调增大,n值呈现出略有增大的趋势,延伸率、r值变化规律不明显,IE值单调下降,板材的拉胀成形性能变差;随着Cu含量增加,T4态合金板材烤漆前后的强度均单调增大,但合金板材模拟烤漆后表现出烤漆软化现象,且其软化量随Cu含量增加而逐渐增大,说明Cu含量增加不利于铝板烘烤硬化性能的发挥.

Effects of Cu content on the formability and bake-hardening ability of Al-1.0Mg-1.0Si-0.6Mn aluminum alloy sheets

The effect of Cu content on the formability and bake-hardening ability of Al-1.0Mg-1.0Si-（0.1～0.7）Cu-0.6Mn alloys used for automotive body sheets in T4 temper processing was investigated by tensile test,cupping test and differential scanning calorimetry（DSC） analysis.The results showed that with increasing Cu content,the strength values of alloy sheets in T4 temper processing increase but the IE values decrease monotonously.At the same time,the n values increase slightly while the elongation and r values change little,and the IE values decrease monotonously and the drawing-bulging formability of alloy sheets become worse.Although the strength values of T4 tempered alloy sheets increase monotonously with increasing Cu content,they usually decrease to somewhat extent after paint-baking treatment,and this softening phenomenon becomes more serious with increasing Cu content.It is thus suggested that the bake-hardening ability of the alloy sheets is deteriorated with increasing Cu content.