时效状态对Al⁃5.9Zn⁃0.8Mg合金压溃性能的影响

Effect of ageing temper on the crushing property of Al-5.9Zn-0.8Mg alloy

摘要:

通过电子万能试验机、透射电镜等，研究了不同时效状态对半连续铸造的Al-5.9Zn-0.8Mg合金压溃性能的影响．结果表明：T4（30 d常温停放）状态试样的抗拉强度接近于T6（T4+120 ℃/24 h）状态试样的抗拉强度，合金表现出强烈的自然时效效应；T7（T6+170 ℃/10 h）状态试样抗拉强度低于T6状态试样，但两状态屈服强度接近；各状态试样的断后综合延伸率（A50）数值在15%~16%之间，T4，T6和T7的均匀延伸率（Ag）分别为15.2%，13.1%和8.5%；均匀塑性变形程度最高的T4状态试样在压溃过程中发生脆性开裂，而出现严重颈缩现象的T7状态试样则能在压溃过程中均匀折皱，其压溃性能最优．

Abstract:

The effects of different aging temper on the crushing behavior of semi-continuous casting Al-5.9Zn-0.8Mg alloy were studied by Electronic Universal Testing machine and Transmission Electron Microscope. The results show that the tensile strength of T4 （30 days at room temperature） is close to that of T6 （T4+120 ℃/24 h） state sample. This alloy shows a strong natural aging behavior. The tensile strength of T7 （T6+170 ℃/10 h） specimen is lower than that of T6 specimen， but the yield strength of the two states is close. The value of comprehensive elongation after fracture （A50） of samples in each temper is 15%-16%. The uniform elongation （Ag） of T4， T6 and T7 specimens are 15.2%， 13.1% and 8.5%， respectively. The T4 temper specimen with the highest uniform plastic deformation undergoes brittle cracking during the crushing process， while the T7 temper specimen with severe necking can wrinkle uniformly in the crushing process. The crushing property of T7 temper is the best.