The corrosion behaviors of 1420 and 2195 Al-Li alloys under 308 and 490 MPa tensile stress respectively in neutral 3.5% NaCl solution were investigated using electrochemical impedance spectroscopy(EIS) and scanning el...The corrosion behaviors of 1420 and 2195 Al-Li alloys under 308 and 490 MPa tensile stress respectively in neutral 3.5% NaCl solution were investigated using electrochemical impedance spectroscopy(EIS) and scanning electron microscope(SEM). It is found that the unstressed 1420 alloy is featured with large and discrete pits, while general corrosion and localized corrosion including intergranular corrosion and pitting corrosion occur on the unstressed 2195 alloy. As stress is applied to 1420 alloy, the pit becomes denser and its size is decreased. While, for the stressed 2195 alloy, intergranular corrosion is greatly aggravated and severe general corrosion is developed from connected pits. The EIS analysis shows that more severe general corrosion and localized corrosion occur on the stressed 2195 Al-Li alloy than on 1420 Al-Li alloy. It is suggested that tensile stress has greater effect on the corrosion of 2195 Al-Li alloy than on 1420 Al-Li alloy.展开更多
The stress corrosion cracking(SCC) susceptibility of an Al-Li-Cu-Mg-Zr alloy(2091), heat-treated under different regime,has been investigated hy means of tensile tests at slow strain rate.The microstructure has been e...The stress corrosion cracking(SCC) susceptibility of an Al-Li-Cu-Mg-Zr alloy(2091), heat-treated under different regime,has been investigated hy means of tensile tests at slow strain rate.The microstructure has been examined with TEM.The deformation characteristic has also been analysed.The stress corrosion resistance of the alloy was revealed to be mainly affected by the covering rate of T_2-phase over grain boundaries and by the average distance between T_2-phase particles. SCC resistance can be obviously improved by predeforming the alloy at room temper- ature to reduce the precipitation of T_2-phase along grain boundaries.展开更多
采用等温热压缩测试和TEM分析研究铝锂合金的流变行为与组织演化规律。结果表明:合金的热塑性变形过程受热激活控制,当变形温度低于410℃时,流变曲线具有明显的峰值应力,曲线由加工硬化、动态软化和稳定阶段3个阶段组成;当变形温度高于...采用等温热压缩测试和TEM分析研究铝锂合金的流变行为与组织演化规律。结果表明:合金的热塑性变形过程受热激活控制,当变形温度低于410℃时,流变曲线具有明显的峰值应力,曲线由加工硬化、动态软化和稳定阶段3个阶段组成;当变形温度高于410℃后,峰值应力不明显。随应变量的增加,合金组织演化规律为产生大量无规则缠结位错→"多边化"形成"位错墙"→分割原始晶粒成若干亚晶→亚晶合并长大并同时经受变形→重复上述过程。应变量的增加导致大量空位产生,刃型位错更易攀移、重组和对消,晶内形成亚晶组织。求解得到合金的材料常数如下:结构因子A为2.787×1016;变形激活能Q为217.397 k J/mol;应力指数n为6.11656;应力水平参数α为0.012568 mm2/N。应变速率和温度对合金流变应力的影响可以用包含Arrhenius等式的Z参数表示。展开更多
基金Project(50401012) supported by the National Natural Science Foundation of China
文摘The corrosion behaviors of 1420 and 2195 Al-Li alloys under 308 and 490 MPa tensile stress respectively in neutral 3.5% NaCl solution were investigated using electrochemical impedance spectroscopy(EIS) and scanning electron microscope(SEM). It is found that the unstressed 1420 alloy is featured with large and discrete pits, while general corrosion and localized corrosion including intergranular corrosion and pitting corrosion occur on the unstressed 2195 alloy. As stress is applied to 1420 alloy, the pit becomes denser and its size is decreased. While, for the stressed 2195 alloy, intergranular corrosion is greatly aggravated and severe general corrosion is developed from connected pits. The EIS analysis shows that more severe general corrosion and localized corrosion occur on the stressed 2195 Al-Li alloy than on 1420 Al-Li alloy. It is suggested that tensile stress has greater effect on the corrosion of 2195 Al-Li alloy than on 1420 Al-Li alloy.
文摘The stress corrosion cracking(SCC) susceptibility of an Al-Li-Cu-Mg-Zr alloy(2091), heat-treated under different regime,has been investigated hy means of tensile tests at slow strain rate.The microstructure has been examined with TEM.The deformation characteristic has also been analysed.The stress corrosion resistance of the alloy was revealed to be mainly affected by the covering rate of T_2-phase over grain boundaries and by the average distance between T_2-phase particles. SCC resistance can be obviously improved by predeforming the alloy at room temper- ature to reduce the precipitation of T_2-phase along grain boundaries.
文摘采用等温热压缩测试和TEM分析研究铝锂合金的流变行为与组织演化规律。结果表明:合金的热塑性变形过程受热激活控制,当变形温度低于410℃时,流变曲线具有明显的峰值应力,曲线由加工硬化、动态软化和稳定阶段3个阶段组成;当变形温度高于410℃后,峰值应力不明显。随应变量的增加,合金组织演化规律为产生大量无规则缠结位错→"多边化"形成"位错墙"→分割原始晶粒成若干亚晶→亚晶合并长大并同时经受变形→重复上述过程。应变量的增加导致大量空位产生,刃型位错更易攀移、重组和对消,晶内形成亚晶组织。求解得到合金的材料常数如下:结构因子A为2.787×1016;变形激活能Q为217.397 k J/mol;应力指数n为6.11656;应力水平参数α为0.012568 mm2/N。应变速率和温度对合金流变应力的影响可以用包含Arrhenius等式的Z参数表示。
