TY - JOUR
T1 - Cracks propagation mechanism of intergranular corrosion in Al–Cu–Li AA2195 alloys governed by constant relative humidity
AU - Zhao, Jingxin
AU - Dan, Zhenhua
AU - Chang, Hui
AU - Zhou, Lian
N1 - Publisher Copyright:
© 2024 The Authors
PY - 2024/9/1
Y1 - 2024/9/1
N2 - Atmospheric corrosion of Al–Cu–Li AA2195 alloys was investigated in constant relative humidity (RH) controlled by saturated salt solutions. Corrosion process was governed by RH, especially for the transformation of corrosion products and crack growth. The deceleration corrosion kinetics and maximum pit depth were found to be in accordance with the power laws. The corrosion products gradually transformed from γ-Al(OH)3 and γ-AlOOH into NaAlCO3(OH)2 and γ-Al(OH)3 affected by RH and exposure time. The localized formation of pitting, filiform and exfoliation corrosion was induced by the presence of Cu/Mg/Li-containing secondary precipitates, including T1(Al2CuLi), θ'(Al2Cu) and S'(Al2CuMg) phases. Secondary precipitates with lower potential were prone to triggering intergranular corrosion. The primary cracks penetrated into the internal matrix along large angular grain boundaires. Secondary cracks propagated along corrosion channels of the stress-concentrated triple grain boundaries with higher schimd factors, larger Kernel average misorientation and higher geometrically necessary dislocation densities. A crack propagation mechanism controlled by RH was proposed.
AB - Atmospheric corrosion of Al–Cu–Li AA2195 alloys was investigated in constant relative humidity (RH) controlled by saturated salt solutions. Corrosion process was governed by RH, especially for the transformation of corrosion products and crack growth. The deceleration corrosion kinetics and maximum pit depth were found to be in accordance with the power laws. The corrosion products gradually transformed from γ-Al(OH)3 and γ-AlOOH into NaAlCO3(OH)2 and γ-Al(OH)3 affected by RH and exposure time. The localized formation of pitting, filiform and exfoliation corrosion was induced by the presence of Cu/Mg/Li-containing secondary precipitates, including T1(Al2CuLi), θ'(Al2Cu) and S'(Al2CuMg) phases. Secondary precipitates with lower potential were prone to triggering intergranular corrosion. The primary cracks penetrated into the internal matrix along large angular grain boundaires. Secondary cracks propagated along corrosion channels of the stress-concentrated triple grain boundaries with higher schimd factors, larger Kernel average misorientation and higher geometrically necessary dislocation densities. A crack propagation mechanism controlled by RH was proposed.
KW - Al-Cu-Li AA2195 alloys
KW - Constant relative humidity
KW - Intergranular corrosion crack propagation
KW - Secondary precipitated phase
KW - Thin electrolyte layers
UR - http://www.scopus.com/inward/record.url?scp=85199479641&partnerID=8YFLogxK
U2 - 10.1016/j.jmrt.2024.07.145
DO - 10.1016/j.jmrt.2024.07.145
M3 - 文章
AN - SCOPUS:85199479641
SN - 2238-7854
VL - 32
SP - 165
EP - 176
JO - Journal of Materials Research and Technology
JF - Journal of Materials Research and Technology
ER -