Sr对AZ31B镁合金微观组织和腐蚀性能的影响

摘要

研究了Sr对AZ31B镁合金显微组织和腐蚀性能的影响。当AZ31B中加入的Sr含量大于0.3％时，合金组织中β相(Mg17Al12)减少，分布更加弥散和均匀，并且在晶界上形成了断续网状分布的Al4Sr相，合金组织明显细化。当AZ31B中加入的Sr含量达到0.9％时腐蚀速率下降为AZ31B的50％。但Sr含量达到1.2％时，晶界处出现共晶组织呈断续网状分布，合金晶粒再度增大。%The effect of strontium on microstructure and corrosion resistance of magnesium alloy was studied. When the addition of Sr was more than 0. 3%, the amount of Mgn AI12 phase in the alloy decreased, and distribution became more uniform, reticular Al4Sr at grain boundaries formed and microstructure of the alloy was also refined obviously. The corrosion rate of AZ31 alloy with an addition of 0. 9% Sr decreased to 50%. This was mainly caused by the formation of reticular AL4Sr phase, which acted as an effective barrier against corrosion and made the corrosion potential increased and the corrosion current density decreased. But when the Sr addition was more than 1. 2%, eutectic structure distributed along with grain boundaries to form discontinued net-like structure and the grain size increased agaia.