拉应力对6N01铝合金蠕变时效组织与性能的影响

Effect of tensile stress on microstructures and properties of creep aged 6N01 aluminum alloy

采用单轴蠕变拉伸试验研究6N01铝合金蠕变时效后组织与性能的变化规律,并结合金相(OM)、扫描电镜(SEM)和透射电镜(TEM)的组织分析与维氏硬度、室温拉伸的力学性能分析,研究蠕变过程中加载的拉应力对6N01铝合金组织与性能的影响。研究结果表明:在180℃/6 h的蠕变时效条件下,加载60 MPa拉应力的试样室温拉伸抗拉强度最大,为341.6 MPa;蠕变时效处理时,加载应力小于60 MPa的试样抗拉强度略比加载应力为60 MPa的试样抗拉强度低;当加载拉应力大于60 MPa时,合金抗拉强度明显下降;当加载拉应力超过60 MPa时,会引起铝基体中析出相粗化,甚至析出相的分布出现应力位向效应,导致合金性能各向异性严重,综合性能变差。

The changing regularity of microstructures and properties of 6 N01 aluminum alloys after the uniaxial tensile-creep test were studied. After creep aging under different tensile stresses, the microstructures of samples were analyzed by optical microscope（OM）, scanning electron microscope（SEM） and transmission electron microscope（TEM）, while the mechanical properties were tested by Vickers hardness and tensile tests. The results show that the sample with 60 MPa loading creep stress has the highest tensile strength（341.6 MPa） after creep aging at 180 ℃ for 6 h, if the loading creep stress of CA treatment is below 60 MPa, the tensile strength would decreases slightly compared with that of 60 MPa loading creep stress. However, when the creep stress exceeds 60 MPa, tensile strength decreases sharply. This is because a greater creep stress would make precipitates coarsen in the aluminum matrix. What＇s more, stress-orienting effect of precipitation may appear, which makes anisotropic performance worse, and therefore, the mechanical properties of the material become worse.