Cu含量对Al-2.5Mg-xCu-0.2Si合金微观组织和性能的影响

研究了Cu含量对Al-2.5Mg-x Cu-0.2Si合金微观组织和性能的影响。结果表明:由于形成Cu、Mg原子团簇,加入Cu的合金的显微硬度在时效初期有明显的快速硬化。随着时效时间的延长,由于S′相和GPB的形成使得合金的硬度再次提高,并达到硬度峰值。快速硬化的硬度值和峰值硬度值均随铜含量的增加而增加。铜含量增高,合金的抗拉强度和屈服强度增加明显,延伸率降低。含铜量增高,合金的抗晶间腐蚀能力变差。当Cu含量低于1.14%(质量分数,下同)时,合金具有良好的抗晶间腐蚀性能;但含铜2.10%的合金抗晶间腐蚀性能显著降低。实验结果表明:含铜量为1.14%的合金具有较好的机械性能和抗腐蚀能力。

Effect of Cu content on microstructure and properties of Al-2.5 Mg-xCu-0.2 Si alloy

Effect of Cu content on microstructure and properties of Al-2.5 Mg-x Cu-0.2 Si alloys was investigated in this research.Results show that the microhardness of the alloy with Cu addition has an obvious rapid hardening effect due to the clustering of Cu and Mg at the early stage of aging.With further aging,the microhardness of the alloy increases again and reaches an obvious second peak due to the formation of S′phase and Guinier-Preston-Bagaryasky(GPB)zone.The increasing amount of Cu content results in a significant increase in tensile strength and yield strength while a reduction of elongation and intergranular corrosion performance.With the increase of Cu content,the intergranular corrosion performance of the alloy becomes worse.The alloy has a reasonably well corrosion performance when the Cu content is less than 1.14 wt%.However,there is a significant reduction when the alloy contains 2.10 wt%Cu.Based on these results,the alloy containing 1.14 wt%Cu has better mechanical properties and corrosion resistance.