材料期刊网

采用显微硬度测试、电导率测试、拉伸力学性能测试以及透射电镜观察，研究时效温度和时效时间对2A14大规格铝合金棒材力学性能和电导率的影响规律。结果表明：在相同的时效时间下，合金电导率随时效温度升高而逐渐升高；在相同的时效温度下，合金电导率随时效时间的延长而逐渐升高。固溶态2A14合金中存在与Al 6 Mn晶体结构相近的Al 12(MnCu)3 Si 2粒子，此Al 12(MnCu)3 Si 2粒子在合金再结晶过程中影响晶界迁移，抑制晶粒在固溶过程中的长大效应；时效后，合金中主要的强化相为S'相，但在140℃(或低于400℃)时效12 h的合金中，强化相数量较少，合金性能与固溶态接近；经160℃、12 h时效后，合金具有较好的综合力学性能，其抗拉强度和屈服强度分别为509 MPa和452 MPa，伸长率为10.1%；在180℃、12 h时效条件下处理后，合金中的S'相会明显粗化，屈服强度和抗拉强度大幅下降，伸长率升高，表现出明显的过时效特征。

The effects of aging temperature and aging time on the mechanical properties and electrical conductivity of 2A14 aluminum alloy were investigated by microhardness test, electrical conductivity test, tensile test and transmission electron microscopy (TEM). The results show that the electrical conductivity of the sample increases gradually with increasing temperature or aging time when the aging time or aging temperature are constant. The Al 12 (MnCu) 3 Si 2 particles found in the solid solution 2A14 alloy has a similar crystal structure with Al6Mn, the Al12(MnCu)3Si2 particles affect the migration of grain boundary during recrystalline process and restrain the grain growth during solid solution. For the 2A14 alloy, theS'phase is the mainly strengthening precipitates. However, for the sample aged at 140℃ (or lower than 140℃) for 12 h, the mechanical properties are close to the sample in solution-treated condition due to less strengthening phase. After aging at 160℃ for 12 h, the alloy shows better combination mechanical properties, the ultimate tensile strength (UTS), yield strength (YS) and elongation are 509 MPa, 452 MPa and 10.1%, respectively. After aging at 180℃ for 12 h, with the increase of aging temperature and extension of aging time, the precipitate size ofS' phase increases and the mechanical properties decrease obviously, which is a typical phenomena of over aging.