摘要
采用显微硬度计、拉伸试验机、电导率测试仪、透射电镜、晶间腐蚀和电化学腐蚀等手段,研究了单级时效、双级时效和回归再时效对Al-6.6Zn-2.2Mg-2.0Cu-0.1Zr合金组织、力学性能和耐腐蚀性能的影响。结果表明,T6态合金的硬度、抗拉强度和规定塑性延伸强度高于双级时效态合金;随着回归时间的延长,合金的硬度先增加而后减小、电导率逐渐增加,抗拉强度和规定塑性延伸强度都呈现单调递减趋势,RRA工艺下试验合金的强度要低于T6态,但是明显高于双级时效态。T6态合金的晶间腐蚀最严重,RRA 175℃×3 h和RRA 195℃×1 h合金的晶间腐蚀较轻且与双级时效态相当,除T6态合金的腐蚀等级为4级外,RRA态和双级时效态合金的腐蚀等级都为3级。RRA 175℃×3h、RRA 195℃×1h合金和双级时效态合金的极化曲线相似、腐蚀电位较为接近,且腐蚀电位都较T6态合金发生正向移动,而腐蚀电流密度都明显低于T6态合金;RRA 175℃×3 h、RRA 195℃×1 h合金和双级时效态合金的耐腐蚀性能相当,且都明显高于T6态合金。
The effects of single-stage aging,double-stage aging and regression re-aging on the microstructure,mechanical properties and corrosion resistance of Al-6.6 Zn-2.2 Mg-2.0 Cu-0.1 Zr alloy were studied by means of microhardness tester,tensile testing machine,conductivity tester,transmission electron microscope,and intergranular corrosion as well as electrochemical corrosion tests.The results show that the hardness,tensile strength and yield strength of the alloy in double-stage aging state are higher than that in the T6 state.With the prolongation of regression time,the hardness of the alloy increases first and then decreases,the electrical conductivity increases gradually,and the tensile strength and yield strength of the alloy show a monotonic decreasing trend.The strength of the alloy in RRA states is lower than that in the T6 state,but significantly higher than that in the double-stage aging state.The intergranular corrosion in the T6 state is the most serious,that in both the RRA 175℃×3 h and the RRA 195℃×1 h states is lighter and comparable to that in the two-stage aging state.Except that in T6 state is grade 4,the corrosion grade of the alloy in all the other states is grade 3.For the RRA 175℃×3 h and RRA 195℃×1 h and two-stage ageing states,the polarization curves and corrosion potentials are similar,while the corrosion potentials are close to that in the T6 state,and the corrosion current density is lower than that in the T6 state.The corrosion resistance of the alloy in the RRA 175℃×3 h and RRA 195℃×1 h states as well as the two-stage aging states are similar,and all are significantly higher than in the T6 state.
作者
李小霞
柯新泽
Li Xiaoxia;Ke Xinze(Department of Civil Engineering,Henan Vocational and Technical College of Architecture,Zhengzhou Henan 450007,China;Department of Materials Engineering,Zhongyuan Institute of Technology,Zhengzhou Henan 450007,China;College of Materials Science and Engineering,Zhengzhou University,Zhengzhou Henan 450001,China)
出处
《金属热处理》
CAS
CSCD
北大核心
2019年第7期62-67,共6页
Heat Treatment of Metals
基金
河南教育教学改革项目(ZJC2000707067)
