2099铝锂合金挤压材料组织与抗腐蚀性能的各向异性研究

Research on Anisotropy of Microstructure and Corrosion Resistance Extruded 2099 Al-Li Alloy

通过金相观察以及晶间腐蚀和剥落腐蚀实验等手段研究了2099铝锂合金挤压材料的组织、抗晶间腐蚀与抗剥落腐蚀性能的各向异性。结果表明:在2099铝锂合金挤压材料中与挤压方向垂直的面上,粗大不(难)溶第二相分布离散,晶粒组织方向性较低,晶间腐蚀深度大、密度低,剥落腐蚀坑离散分布;而在与挤压方向平行的面上,粗大不(难)溶第二相沿挤压方向排列,晶粒沿挤压方向呈带状分布,并在局部区域发生再结晶,晶间腐蚀深度浅、密度高,剥落腐蚀坑密度高。粗大不(难)溶第二相和晶粒分布的各向异性与其抗晶间和剥落腐蚀性能的各向异性是一致的。

The anisotropy of microstructure and corrosion resistance extruded 2099 Al-Li alloy were investigated by OM, intergranular and exfoliation corrosion test. The results show that, in the surfuce perpendicular to the extrusion direction, bulky insoluble second phase is dispersive and grain structure has not obvious orientation. The surfuce intergranular corrosion has great depth but low density and exfoliation corrosion pits have a discrete distribution. In the swrfuce parallel to the extrusion direction, bulky insoluble second phase arranges along the extrusion direction. Grain structure presents zonal distribution along the extrusion direction. It also has recrystallization grains in local area. The surfuce intergranular corrosion has shallow depth but high density. Its exfoliation corrosion pits also have a high density. The anisotropy of both bulky insoluble second phase and grain distribution has a consistency with the anisotropy of both intergranular corrosion and exfoliation corrosion.