腐蚀条件对Al-Zn-Mg铝合金强韧性能的影响

Effect of corrosion conditions on strength and toughness of Al-Zn-Mg aluminum alloys

采用硬度、电导率、拉伸和卡恩撕裂性能测试,结合差示扫描量热法(DSC)、金相显微镜(OM)、扫描电镜(SEM)和透射电镜(TEM)研究不同腐蚀条件对Al-Zn-Mg铝合金强韧性能的影响。结果表明:经(25℃,3.5%NaCl;50℃,3.5%NaCl;100℃,3.5%NaCl;25℃,6%NaCl)腐蚀液浸泡后,材料的强度受腐蚀液温度和浓度的影响,随着3.5%NaCl腐蚀液温度的升高,材料的强度呈现一种先降低后升高的趋势,相对于未腐蚀材料,当温度从50℃变化到100℃时,3.5%NaCl腐蚀液浸泡后的材料强度上升比较明显,为11.51 MPa;当温度为25℃时,6%NaCl腐蚀液中材料强度下降较大为10.25 MPa;材料的韧性则随着腐蚀液温度、浓度的升高而降低;经(100℃,3.5%NaCl)腐蚀液浸泡后,材料的韧性与未腐蚀材料有明显差别,韧性值下降10.4%,挤压方向与垂直挤压方向的韧性差值由原来的13.4 N/mm增大为32.4 N/mm。

The effect of different corrosion conditions on the strength and toughness of Al-Zn-Mg aluminum alloys was investigated by hardness, electrical conductivity, tensile test, Kahn tear test, differential scanning calorimetry（DSC）, optical microscopy（OM）, scanning electron microscopy（SEM） and transmission electron microscopy（TEM）. The results show that, after immersion in（25 ℃, 3.5%NaCl; 50 ℃, 3.5%NaCl; 100 ℃, 3.5%NaCl; 25 ℃, 6%NaCl） etching solution, the temperature and concentration of etching solution have effects on the strength of the material. With the temperature rise of 3.5%NaCl etching solution, the strength decreases firstly, and then increases, and the strength increases by 11.51 MPa when the temperature varies from 50 ℃ to 100 ℃. While the material is soaked in etching solution at the temperature of 25 ℃, the strength of material soaked in 6%NaCl etching solution decreases by 10.25 MPa compared with that of the free-corrosive material. The toughness decreases with the temperature rise of the etching solution and etching solution concentration. There are obvious differences between free-corrosive material and the material soaked in 3.5%NaCl etching solution at the temperature of 100 ℃, the toughness decreases by 10.4%, and the toughness difference varies from 13.4 N/mm to 32.4 N/mm between the extrusion orientation and vertical extrusion orientation.