Al-Cu-Mg-Ag-(Sc)合金的显微组织与腐蚀性能

采用铸锭冶金工艺,制备不同钪含量的Al-Cu-Mg-Ag合金.通过金相显微镜、扫描电镜、透射电镜、晶间腐蚀及剥落腐蚀等实验方法,研究钪对Al-5.3Cu-0.8Mg-0.6Ag合金的组织和腐蚀性能影响.结果表明:添加0.3%～0.5% Sc可明显细化铸态合金的晶粒,平均晶粒尺寸从300 μm降低到60 μm,而添加0.1%～0.3% Sc有助于提高挤压态合金抗腐蚀性能.但当添加0.5% Sc时,合金中形成粗大的Al3(Sc, Zr)稀土化合物相,导致合金的抗蚀性能降低.

Microstructure and corrosion properties of Al-Cu-Mg-Ag-(Sc) alloys

The Al-Cu-Mg-Ag alloys with different scandium contents were prepared by ingot metallurgy technology. The effect of scandium addition on microstructure and corrosion properties of Al-5.3Cu-0.8Mg-0.6Ag-0.2Zr alloy was investigated using optical microscope, scanning electron microscope (SEM), transmission electron microscope (TEM), intergranular corrosion and exfoliation corrosion. The result shows that 0.3%?0.5% Sc addition refines the grains of the casting alloys and the average grain size decreases from 300 μm to 60 μm. Increasing Sc content from 0.1% to 0.3% increases corrosion-resistance properties of the extruded alloys. However, the coarsening Al3(Sc, Zr) compounds in the extruded alloys with 0.5% Sc decrease corrosion-resistant properties seriously.