摘要
采用硬度测试、恒温浸泡方法、金相和透射电镜技术研究不同温度不同时间的单级时效处理对7050铝合金的力学性能和晶间腐蚀性能的影响。结果表明:当时效温度由120℃升高至180℃时,合金时效硬化响应速度明显加快,合金进入过时效状态所需的时间缩短。合金在120℃峰时效时,随时效时间的延长,析出相的粗化、晶界的宽化和无沉淀析出带出现缓慢,合金的硬度能长时间维持在较高水平。合金的晶间腐蚀敏感性与晶界析出相和无沉淀析出带(PFZ)的特征有关;晶界析出相呈链状分布时合金的腐蚀敏感性强,晶界析出相大,分布不连续,PFZ的宽化,则合金的腐蚀敏感性低。
The mechanical properties and intergranular corrosion performance of 7050 A1 alloy were investigated at different aging temperature and time by hardness tests, constant temperature immersion corrosion method, polarization curve measure, optical microscopy and transmission electron microscopy （TEM）. The results show that the aging response rate is greatly accelerated with elevating the aging temperature from 120 ℃ to 180 ℃, and the time achieved to overaged stage is remarkably decreased. Alloy in 120 ℃ peak time, along with the aging time increase, the equilibrium phase＇ coarsening, grain boundaries＇ widening and precipitated free zone （PFZ）＇ appearing change slowly, the hardness of the alloy can long time maintain at high levels. Corrosion sensibility of alloy is related to characteristics of equilibrium phase and precipitated free zone （PFZ） at grain boundaries. When grain-boundary equilibrium phase have reticulate or chain distribution, the corrosion sensibility of alloy is high. On the contrary, with the equilibrium phase discontinuous and PFZ widening, the corrosion sensibility of the alloy decreases.
出处
《热加工工艺》
CSCD
北大核心
2012年第22期194-197,共4页
Hot Working Technology
关键词
7050铝合金
硬度
显微组织
晶间腐蚀
7050 A1 alloy
hardness
microscopic structure
intergranular corrosion
