高锌超高强铝合金强韧化工艺研究

Research on Strengthening-toughening Techniques of Super-high Strength Aluminum Alloy with High Zinc Content

采用硬度测试、拉伸性能、紧凑型拉伸、透射电子显微镜等方法,研究了单级时效和双峰时效对高锌Al-Zn-Mg-Cu合金强度、断裂韧性的影响。以及时效过程中合金显微组织变化规律。研究结果表明:合金最佳单级时效工艺为120℃/24 h,此时合金晶内析出细小弥散的GP区和η'相,晶界析出相连续分布。此时合金强度最高,断裂韧性较差。最佳的双峰时效工艺为120℃/24 h+190℃/10 min,双峰时效处理后合金晶内分布着细小的η'相和少量GP区,晶界析出相断续分布。此时合金的强度相比于T6状态略有降低,断裂韧性大大提高。

The influence of different ageing treatments on the properties and fracture of super-high strength aluminum alloy with high zinc content were investigated by means of tensile and toughness, TEM. The results show that the optimal single-stage peaked-ageing treatment is 120 ℃/24 h, at that condition, the alloy owned high ulti- mate strength and low fracture toughness. There are plenty of GP zone and ＂η＇phase in the grains, continuous GBPs. The optimal double-peaks ageing treatment is 120 ℃/24 h ＋ 190 ℃/10 min, at that condition , there are η＇phase and GP zone in the grains, unconscious GBPs. The strength of the alloy is lower than that treated by T6 treatment but the fracture toughness is much higher.