Al-5.2Cu-0.4Mg-1.02Ag合金板材组织性能的研究

Microstructure and Properties of Al-5.2Cu-0.4Mg-1.02Ag Alloy Plate

通过显微硬度测试、力学性能测试、透射电镜分析等手段研究了Al-5.2Cu-0.4Mg-1.02Ag合金板材在欠时效、峰时效、过时效的力学性能和显微组织。结果表明:合金主要强化相是Ω相和θ′相,它们之间存在竞相析出与长大的关系。欠时效时出现大量细小的Ω相和少量的θ′相,尺寸约为15nm;峰时效时Ω相长大且θ′相增多,Ω相的体积分数达到最大值,尺寸约为40～60nm,θ′相的尺寸约为40nm;过时效Ω相体积分数有所减少而θ′相体积分数有所增加,θ′相尺寸约为70～100nm,且有部分θ′相转变为θ相。峰时效时合金的抗拉强度和屈服强度达到最大值,断后延伸率随时效时间的延长有下降的趋势。

The microstructure and mechanical properties of Al-5.2Cu-0.4Mg-1.02Ag （ % , mass fraction） alloy plate during under-ageing, peak-ageing and over-ageing stages were investigated by means of microhardness test, mechanical property test and transmission electron microscope. The results showed that the main precipitated phases were Ω phase and θ′ phase which precipitated and grew ahemantly. A plenty of Ω phase and a small amount of θ′ phase were found in the under-aged alloy, both of which were about 15 nm. In peak-ageing, the number of θ′ phase increased and 12 phases grew up, in which the volume fraction of Ω phase increased. The size of Ω phase and θ′ phase was about 40 -60 nm, 40 nm, respectively. In subsequent over-ageing, the number of phase decreased and the number of θ′ phase increased which size was about 70 - 100 nm and part of θ′ phase transformed into θ phase. The maximum tensile strength and yield strength were gained at peak-ageing, in addition, the elongation decreased with the extension of ageing time.