摘要
The microstructure-dependent corrosion resistance of dual structured fine-grained Mg-7.5 Li-3 Al-lZn has been investigated.The alloys were extruded using extrusion with a forward-backward rotating die(KoBo,a newly developed SPD method)at two different extrusion ratios.The fine-grained microstructures formed in the alloys were characterized,and the influence of grain refinement on corrosion resistance was analyzed.For fine-grained(α+β)Mg-Li alloys,a higher extrusion ratio led to more intensive grain refinement;however,this relationship did not improve their corrosion resistance in a chloride-containing solution.The corrosion resistance of the alloys was mainly controlled by the refinement ofα(Mg)andβ(Li),along with the distribution of second phases.The presence of MgLi_(2) Al at grain boundaries facilitated their dissolution.
