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研究了不含Zn及0.72%Zn微合金化的Al-3.7Cu-1.15Li-0.5Mg合金T6态时效(150及175℃)不同时间后的晶间腐蚀行为,建立了其腐蚀-时效进程状态图。结果表明,Zn微合金化铝锂合金晶间腐蚀敏感性略低于不含Zn微合金化的铝锂合金。随时效进程的发展,铝锂合金腐蚀类型变化规律为:孔蚀或局部晶间腐蚀(时效早期),全面晶间腐蚀(欠时效阶段),局部晶间腐蚀(近峰时效阶段),孔蚀(过时效阶段)。晶间腐蚀深度随时效时间延长呈先增加而后降低的规律。时效时间延长,一方面晶界析出相逐渐粗化并且呈不连续分布,另一方面晶内T1相及θ相析出,晶内电位降低,晶界及晶内电位差减小,从而导致上述腐蚀类型的变化。
The intergranular corrosion behavior of Al-3.7Cu-1.15Li-0.5Mg alloy aged at different temperatures (150 and 175 ℃) was investigated in a T-free state of Zn-free and 0.72% Figure The results show that the susceptibility to intergranular corrosion of Zn microalloyed Al-Li alloy is slightly lower than that of Al-Li alloy without Zn microalloying. With the development of aging process, the variation law of the corrosion types of Al-Li alloys is as follows: pitting corrosion or local intergranular corrosion (early aging), intergranular corrosion (under aging), local intergranular corrosion (near peak aging), pitting corrosion (Over-aging stage). The depth of intergranular corrosion increases with the aging time first increased and then decreased. On the other hand, T1 phase and θ phase are precipitated in the grain, the potential in the crystal decreases, and the potential difference between the grain boundary and the crystal decreases, resulting in the above-mentioned corrosion Type of change.