晶界结构在不同热处理下对铝镁合金腐蚀规律的研究现状

铝镁合金是未来应用汽车领域发展具有很大潜力的一类重要材料.通常,在商品中的铝镁合金,镁的质量分数在0.5%～13%.汽车制造商通常选用镁的质量分数在4.5%以上,然而研究发现,当镁的质量分数超过3%的时候,会引起晶界间腐蚀,从而造成应力腐蚀开裂.此现象未见文献对其进行系统的分析和研究.本文主要介绍铝镁合金在不同的热处理...

Localised Corrosion and Stress Corrosion Cracking of Aluminium-magnesium Alloys

Al–Mg 5xxx series alloys containing more than 3% magnesium can become susceptible to intergranular corrosion (IGC) and stress corrosion cracking (SCC) owing to precipitation of β–phase (Al3Mg2) at the grain boundaries. This has limited usage of 5xxx series alloys for load–bearing structures in automotive applications. In this work, the effect of various heat treatments on IGC and SCC susceptibility of AA5182 (Al–4.5% Mg) was investigated, and the relationship between grain boundary crystallography and grain boundary precipitation of β–phase, as well as local corrosion of grain boundaries was also studied.