Analysis on black line defects in 7055 aluminum alloy extrusion profiles

doi:10.13251/j.issn.0254-6051.2020.01.048

Abstract

Abstract: “Black line”defects on the surface of 7055 aluminum alloy extrusion profiles after anodic oxidation were identified by high-magnification optical microscope combined with energy spectrum analysis. The results show that the “black line” defects are caused by AlZr aggregation. Such defects can be eliminated by strictly controlling the quality of raw materials, improving the microstructure of AlZr master alloy, properly reducing the content of Zr element in the alloy composition range, increasing the heating temperature and time in the melting process, and melting the Al ₃ Zr particles.

Key words: 7055 aluminum alloy, anodic oxidation, AlZr master alloy, black line defects

CLC Number:

TG115

Zhang Jiangbin, Chen Yuanqing, He Kezhun, Li Jian. Analysis on black line defects in 7055 aluminum alloy extrusion profiles[J]. HTM, 2020, 45(1): 251-253.

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