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本文利用扫描电镜,光学显微镜和表面3D显微镜、晶间腐蚀和剥落腐蚀试验方法等研究两种厚度的5083 H116铝合金板微观腐蚀行为,结果表明:铝板不同厚度处其微观组织特征不同,如晶粒形状,β相(Mg2Al3或Mg5Al8)尺寸和含量等;β相含量较高的试样对晶间腐蚀比较敏感,发生再结晶的表面区域晶界上容易沉积连续的β相,晶间腐蚀试验后可观察到网状晶界;β相含量较低且均匀弥散分布的表面区域表现出较低的晶间腐蚀敏感性,冷变形后形成的平直且定向分布的晶界有利于晶间腐蚀向深处发展;铝板近表面β相较细小且分布均匀的区域表现出良好的抗剥落腐蚀性能,中心区域β相尺寸稍大,剥落腐蚀试验面腐蚀深度稍有增加,β相尺寸增大、含量增多则容易诱发点蚀。
In this paper, the microscopic corrosion behavior of 5083 H116 aluminum alloy plates with two thicknesses was investigated by means of SEM, optical microscope and surface 3D microscope, intergranular corrosion and exfoliation corrosion test. The results show that the microstructure of the aluminum plate is different under different thickness, Grain shape, β-phase (Mg2Al3 or Mg5Al8) size and content, etc .; samples with higher β-phase content are more susceptible to intergranular corrosion; continuous β phase is easy to deposit on the recrystallized grain boundaries, intergranular corrosion test And the reticular grain boundaries can be observed. The surface areas with low and uniform β phase content exhibit lower susceptibility to intergranular corrosion. The flat and oriented grain boundaries formed after cold deformation are conducive to intergranular corrosion And developed to the deep. The region with thin and uniform distribution of β on the surface of aluminum plate showed good anti-spalling corrosion performance. The β phase size in the central region was slightly larger, the corrosion depth of the flaking corrosion test surface slightly increased, the β phase size increased, Increased content is easy to induce pitting.