Ti和Ce对AlMgSi基合金板材成形性能的影响

Effect of Ti and Ce on forming properties of new type AlMgSi based alloy sheet

采用DSC ,EDS ,SEM及TEM等分析手段 ,研究了微量Ti和Ce对新型AlMgSi基铝合金汽车车身板材成形性能的影响。结果表明 :对含 0 .2 5 %～ 0 .2 7%Ti(质量分数 )的铝合金中 ,Ti除了作为异质核心起细化晶粒作用外 ,还分布于晶界 ,通过抑制α(Al)晶粒生长有效地细化组织 ,提高成形性能 ;Ce的加入提高了 β″相的激活能 ,降低了 β′相的激活能 ,从而促使形成 β′相 ,降低板材的抗拉强度 ,使屈强比增大 ,从而不利于成形性能。同时还研究了过剩Si和Mg2 Si对板材性能的影响。

The influence of Ti, Ce elements on forming properties of new type AlMgSi based alloy auto body sheet was studied systematically by using DSC, SEM, EDS and TEM. The results show that, 0.25%～0.27%Ti(mass fraction) is advantageous to refining microstructure as heterogeneous nucleus and to restricting the growth of α(Al) grains through the distribution on the grain boundaries, so that the forming properties of AlMgSi based alloy sheet are improved. The addition of Ce increases the activation energy of β″ phase and decreases that of β′ phase, so the formation of β′ phase is promoted. Therefore the tensile strength of AlMgSi based alloy sheets is decreased and the ratio of yield strength and tensile strength is increased, which harms to the forming properties. Besides, the effect of contents of excessive Si and Mg 2Si of AlMgSi based alloy sheets was studied.