铝锂合金晶间腐蚀敏感性与时效阶段的相关性  

Dependence of Intergranular Corrosion Sensitivity of Al-Li Alloys on Aging Stage

作　　者：蔡超[1] 李劲风[2] 王恒[1] 方娜[1] 许龙[2] 

机构地区：[1]宁夏大学,宁夏银川750021 [2]中南大学,湖南长沙410083

出　　处：《稀有金属材料与工程》2015年第10期2523-2528,共6页Rare Metal Materials and Engineering

基　　金：宁夏自然科学基金(NZ13012)

摘　　要：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（IGC） behaviors of Zn free and Zn micro-alloyed Al-3.7Cu-1.15Li-0.5Mg alloys with T6 aging at 150 and 175 °C for various time was investigated, and a corrosion diagram associated with aging process was established. The results show that the IGC sensitivity of the Zn microalloyed Al-Li alloy is a little lower than that of the Zn free Al-Li alloy. With aging progress, the corrosion mode changes in the following order： pitting and local IGC（initial aging stage）, general IGC（under-aging stage）, local IGC（near peak-aging stage） and pitting（over-aging stage） again. With aging time extension, the IGC depth is increased firstly and then decreased. The grain boundary precipitates are coarsened and their spacing is increased with aging process. In addition, the grain potential is decreased due to the precipitation of T1 and θ phases within grains, and the potential difference between grain and grain boundary is therefore lowered. These two factors result in the above IGC sensitivity variation with aging process.

关 键 词：铝锂合金 晶间腐蚀 时效 

分 类 号：TG166.3[金属学及工艺—热处理] TG146.21[金属学及工艺—金属学]