自然时效对7N01铝合金组织和性能的影响

Effect of Natural Ageing on Properties and Microstructure of 7N01 Aluminum Alloys

通过电导率、力学性能测试和高分辨电镜分析研究了自然时效对7N01合金组织和性能的影响。结果表明:在自然时效中,由于过饱和固溶体不均匀析出与基体共格的析出相,合金电导率随着自然时效时间的延长逐渐降低,时效20 d后基本达到稳定状态。合金的强度随着时效时间的延长逐渐增大,在20 d后达到稳定,抗拉强度在400 MP以上,屈服强度在260 MPa以上,合金的延伸率在自然时效1 d后达到稳定值(约为15.5%)。稳定态合金的强化相主要为尺寸较小的GPⅡ区。此外,弯折试验表明合金具有良好的弯折性能,在自然时效10～60 d内未出现肉眼可见的裂纹。

The influence of natural ageing on the properties and microstructure of 7N01 aluminum alloys was investigated by electrical conductivity,tensile test and high resolution transmission electron microscopy（HREM）.It showed that the non-homogeneous phases were coherent with the matrix precipitates in the process of natural ageing,which causing the electrical conductivity decreased and reached a stable value after about 20 d.The strength of experimental alloys increased gradually and reached a stable value after about 20 d,and the tensile strength was higher than 400 MPa,the yield strength higher than 260 MPa.The elongation reached stable value（about 15.5%） after 1 d in natural ageing.The main strength phases were small and non-homogeneous GPⅡ phases.In addition,the experimental alloy had good resistance against crippling test since that macroscopic crack was not determined as the time increasing from 10 to 90 d in the process of natural ageing.