Cu含量对Al-Cu-0．4Mg-0．6Ag合金组织与力学性能的影响

Effect of Cu Content on Microstructure and Mechanical Properties of Al-Cu-0.4Mg-0.6Ag Alloy

通过拉伸测试、差热分析(DSC)、扫描电镜(SEM)及透射电镜(TEM),研究Cu含量对Al-Cu-0.4Mg-0.6Ag合金的显微组织与力学性能影响。结果显示,增加Cu的含量,能提高合金的时效硬化与抗拉强度。添加8.0%Cu合金的室温抗拉强度从434MPa增大到559MPa,延长率保持在9%以上,300℃时,合金的抗拉强度从141MPa增大到228MPa。185℃峰时效时,Al-Cu-0.4Mg-0.6Ag合金的主要强化相由片状Ω相和少量θ′相组成。随着Cu含量的增加,峰时效态合金中的Ω相体积分数增大。提高Cu的含量不仅能提高合金的固溶强化与时效强化作用,而且过量的Cu生成的θ(CuAl2)相能起到弥散强化的作用,有助于提高合金的高温性能。

The effect of Cu content on the microstructure and mechanical properties of Al-Cu-0.4Mg-0.6Ag alloys is investigated by tensile testing, differential scanning calorimetry （DSC）, scanning electron microscopy （SEM） and transmission electron microscopy （TEM）. It is shown that the artificial aging process of the alloys is improved and the tensile strength is increased with the increase of the Cu content, Cu content from 4.0 % increased to 8.0 %, the tensile strength of the alloy is increased to 559MPafrom 434MPa at the room temperature, and to 228MPa from 141MPa at 300°C , respectively. The specific elongation of the alloy with 8.0 % Cu is more than 9 % at the room temperature. The coherent plate-like Ω phase and a small amount of θ＇ phase are the predominant hardening phases in the Al-Cu-0.4Mg-0.6Ag alloys at peak-aged stage at 185°C and the quantity of the Ω phase is increased with the increase of the Cu content. The increase of the Cu content not only improves the solid solution strengthening effect, hut also increases the content of θ （CuAl2）phase, which shows dispersion strengthening effect, so it is helpful to improve the high temperature performance of the alloy.