摘要
The intergranular corrosion behavior of 2050 Al-Li alloy subjected to non-isothermal aging(NIA)treatment with varying pre-deformation amounts was investigated.Results indicate that the resistance to intergranular corrosion improves with increasing pre-deformation amouts.However,when the pre-deformation amount reaches 20%,the corrosion resistance deteriorates.Microstructural analyses via transmission electron microscopy(TEM)and electron backscatter diffraction(EBSD)reveal that as pre-deformation amount increases,the fraction of high-angle grain boundaries(HAGBs)decreases,while the proportion of low-angle grain boundaries(LAGBs)increases.This change provides additional nucleation sites for precipitates,leading to a reduction in T1 phase size and an increase in T1 phase density.The finer T1 phases contribute to a lower localized potential difference within the grains,slowering corrosion propagation.Furthermore,during corrosion,preferential dissolution of Li results in Cu enrichment along grain boundaries,which further reduces the intergranular corrosion resistance.
研究了不同预变形量2050 Al-Li合金经非等温时效处理后的晶间腐蚀行为。结果表明,随着预变形量的增加,合金的腐蚀性能得到提高。然而,当预变形量增加到20%时,晶间腐蚀抗力降低。透射电子显微镜和背散射电子衍射等显微组织测试表明,随着预变形量的增加,大角度晶界比例降低,小角度晶界比例增加。析出相的形核位置增加,导致T1相尺寸减小、密度增加。细小的T1相导致晶内局部电势差下降,从而减慢腐蚀进程。此外,在腐蚀过程中Li元素的优先腐蚀导致Cu元素在晶界处富集,从而降低合金的晶间腐蚀性能。
基金
supported by the Postdoctoral Fellowship Program of CPSF,China(No.GZC20242033)
the National Science and Technology Research Program of China(No.JPPT2023PXY01).
