Sn含量对轧制Mg-6Bi-Sn合金组织演变和腐蚀性能的影响

研究了轧制态Mg-6Bi-xSn (x=0，1，2，3，%，质量分数) 4种合金的组织演变和腐蚀性能。结果表明：研究合金均表现出等轴晶组织和少量的孪晶组织，随着Sn含量的增加，平均晶粒尺寸分别为 (15.63±1.37)，(13.71±1.15)，(10.86±1.39) 和 (12.29±1.15) μm；第二相体积分数分别为 (3.56±0.06)%，(3.67±0.09)%，(3.76±0.36)%和 (9.58±0.69)%。另外，随着Sn含量的增加，腐蚀速率先减小再增大，这是因为晶粒细化和第二相颗粒增加竞争机制的结果，Mg-6Bi-2Sn合金由于其均匀的微观组织而表现出最佳的耐腐蚀性能。

Effect of Sn Content on Microstructure Evolution and Corrosion Properties of Rolling Mg-6Bi-Sn Alloy

The microstructure evolution and corrosion properties of as-rolled Mg-6Bi-xSn (x=0, 1, 2 and 3, %, mass fraction) were studied. The results revealed that the alloy shows the equiaxial crystal structure combined with small fraction of twinning, with the increase of Sn contents, the average grain size (AGS) was about (15.63±1.37), (13.71±1.15), (10.86±1.39), (12.29±1.15) μm and the volume fraction of the second phase particles was (3.56±0.06)%, (3.67±0.09)%, (3.76±0.36)% and (9.58±0.69)%, respectively. In addition, the corrosion rate decrease firstly and then increase later with increasing Sn contents is mainly due to the competitive between grain refinement which reduce the corrosion rate and more second phase particles which increases the corrosion rate. Finally, Mg-6Bi-2Sn alloy shows the best corrosion resistant performance due to its uniform structure.