预拉伸对Al-Li合金应力腐蚀行为的影响

 在时效前对Al-Li-Cu-Mg-Zr合金进行拉伸变形,用慢应变速率拉伸试验和恒应变三点弯曲试验研究了合金的在3.5％NaCl水溶液中的应力腐蚀行为,并测定了合金的拉伸性能。表明预拉伸变形提高了合金的应力腐蚀抗力和强度。预拉伸变形量4％时,合金具有最低的应力腐蚀开裂敏感性和最高的断裂延伸率。预拉伸变形量从4％至8％时,对合金应力腐蚀开裂敏感性影响不大,合金的延伸率下降也不明显。用透射电镜分析了合金的显微组织与应力腐蚀性能及拉伸性能之间的关系。

EFFECT OF STRETCHING DEFORMATION PRIOR TO AGING ON STRESS CORROSION CRACKING BEHAVIOR OF Al-Li ALLOY

The stress corrosion cracking (SCC) Behavior in 3.5% NaCl solution of Al-Li-Cu-Mg-Zr alloy stretched prior to aging has been studied by the slow strain rate and constant strain test, and its tensile properties have been tested. The results show that the predeformation raises the SCC resistance and strength of the alloy. The alloy predeformed 4% for strecth has the lowest susceptibility on the SCC and the highest utmost elongation. Increasing the stretch from 4% to 8% has no observable effect on the SCC susceptibility and causes no obvious decrease of the elongation of the expriment alloy. The correlation between the SCC behavior, tensile properties and the micorstructure of the alloy was inverstigated by means of transmission electron microscopy (TEM).