轧制工艺对5A12和5A12+0.2Sr铝合金组织及性能的影响

Effect of rolling process on microstructure and properties of 5A12 and 5A12+0.2Sr aluminum alloys

通过电化学极化曲线、晶间腐蚀等试验方法,并结合光学显微镜、扫描电镜等手段观察分析合金腐蚀前后的微观组织演变,研究了两种轧制工艺对5A12及5A12+0.2Sr铝合金的显微组织、力学性能和抗晶间腐蚀性能的影响。结果表明:热轧总变形量为70%时,大应变轧制板材均发生了明显的动态再结晶,其中,5 A12+0.2Sr合金再结晶程度更高;而传统多道次热轧板材则仍保持伸长的纤维状组织。对稳定化处理后的4种试验合金进行150℃×7 d的敏化处理,发现大应变轧制工艺及添加Sr元素均能有效抑制5A12合金的“时效软化”现象,且由传统多道次轧制制备的5A12+0.2Sr合金具有最优的抗晶间腐蚀性能。

The microstructure and properties of 5A12 and 5A12+0.2Sr aluminum alloys were investigated in terms of different rolling process by means of electrochemical polarization curves,intergranular corrosion test,metallographic analysis and scanning electron microscopy.The results show that when the total hot rolling deformation is 70%,obvious dynamic recrystallization can occurre in the large strain rolled sheet,and the recrystallization degree of 5A12+0.2Sr alloy is higher.However,the traditional multi-pass hot-rolled sheet still maintains elongated fibrous structure.The sensitization treatment results of four stabilized experimental alloys at 150℃for 7 days show that the aging softening phenomenon of 5A12 alloy can be effectively inhibited by large strain rolling process and adding Sr element,and the 5A12+0.2Sr alloy obtained by traditional multi-pass rolling has the best intergranular corrosion resistance.