淬火水温对Al-Mg-Si系合金力学性能和耐腐蚀性的影响

采用拉伸性能测试、光学显微镜、扫描电镜和电化学性能测试等方法研究了固溶处理时冷却水温度对Al-Mg-Si系合金性能的影响。结果表明:固溶处理时,随着淬火水温的升高,合金的抗拉强度、屈服强度变化不明显,而合金的伸长率与硬度有所降低,即20 ℃水温淬火时合金具有良好的综合力学性能,显微硬度为129.4 HV0.3,抗拉强度为 352.2 MPa,屈服强度为 300.9 MPa;同时合金的抗晶间腐蚀性逐渐下降,而抗剥落腐蚀性影响不大,均为PC等级。因此,20 ℃水温淬火时合金具有最佳的抗晶间腐蚀性能,最大腐蚀深度为231.4 μm,这与电化学性能测试结果相对应,此时的腐蚀电位最大,为-0.834 V。

Effect of quenching water temperature on mechanical properties and corrosion resistance of Al-Mg-Si series alloy

Effect of water temperature on properties of Al-Mg-Si series alloy during solution treatment was studied by means of tensile properties test, optical microscope, scanning electron microscopy, and electrochemical performance test. The results show that with the increase of quenching water temperature during solution treatment, the tensile strength and yield strength of the alloy are not changed significantly, and the elongation and hardness of the alloy are decreased, that is, the alloy has good comprehensive mechanical properties when quenched at 20 ℃, the microhardness, the tensile strength and the yield strength are 129.4 HV0.3, 352.2 MPa, 300.9 MPa, respectively.Meanwhile, the resistance to intergranular corrosion of the alloy is gradually decreased, but the resistance to spalling corrosion is changed a little, which are both PC grades. Therefore, the alloy has the best resistance to intergranular corrosion when quenched in water at 20 ℃, and the maximum corrosion depth is 231.4 μm, which is in accord with the results of electrochemical performance test, the maximum corrosion potential is -0.834 V.