微观结构对TIG焊接1579合金耐腐蚀性的影响

Effect of Microstructure on the Corrosion Resistance of TIG Welded 1579 Alloy.

作者信息

Gnedenkov Andrey S, Sinebryukhov Sergey L, Mashtalyar Dmitry V, Imshinetskiy Igor M, Vyaliy Igor E, Gnedenkov Sergey V

机构信息

Institute of Chemistry of FEB RAS, 159 Pr. 100-letiya Vladivostoka, Vladivostok 690022, Russia.

School of Engineering, Far Eastern Federal University, 8 Sukhanova St., Vladivostok 690950, Russia.

出版信息

Materials (Basel). 2019 Aug 16;12(16):2615. doi: 10.3390/ma12162615.

DOI:10.3390/ma12162615

PMID:31426372

原文链接:https://pmc.ncbi.nlm.nih.gov/articles/PMC6721039/

Abstract

The paper studies microstructure, chemical composition and corrosion activity of the tungsten inert gas welded joint of the Al-Mg-Sc alloy. An intensive corrosion attack of the heat affected zone (HAZ) was found due to precipitation of secondary phases at recrystallized grain boundaries. The ccorrosion process initiated along the boundary of α-Al grains, where a high concentration of anodic (MgSi and MgAl) and cathodic phases ((MnFe)Al) was observed. Increased temperatures during welding led to coalescence of the anodic phases in HAZ. Additionally, HAZ was found to be enriched with hard intermetallic compounds (MgSi and (MnFe)Al). This area had a higher microhardness (930 MPa) compared to base metal (BM, 895 MPa) and fusion zone (FZ, 810 MPa). The volume fraction of secondary phases was 26% in BM, 28% in FZ and 38% in HAZ. The average grain size increased in the following order: (9 ± 3) µm (BM) < (16 ± 3) µm (HAZ) < (21 ± 5) µm (FZ). A plasma electrolytic oxidation (PEO) coating of aluminum-based material was applied to protect the weld from oxidation. The PEO-coating provided a high corrosion protection in the aggressive Cl-containing environment.

摘要

本文研究了Al-Mg-Sc合金钨极惰性气体焊接接头的微观结构、化学成分和腐蚀活性。由于在再结晶晶界处析出第二相，发现热影响区（HAZ）受到强烈的腐蚀侵蚀。腐蚀过程沿着α-Al晶粒的边界开始，在那里观察到高浓度的阳极相（MgSi和MgAl）和阴极相（(MnFe)Al）。焊接过程中温度升高导致热影响区阳极相的合并。此外，发现热影响区富含硬质金属间化合物（MgSi和(MnFe)Al）。与母材（BM，895MPa）和熔合区（FZ，810MPa）相比，该区域具有更高的显微硬度（930MPa）。第二相的体积分数在母材中为26%，在熔合区中为28%，在热影响区中为38%。平均晶粒尺寸按以下顺序增加：(9±3)µm（母材）<(16±3)µm（热影响区）<(21±5)µm（熔合区）。采用铝基材料的等离子体电解氧化（PEO）涂层来保护焊缝免受氧化。PEO涂层在腐蚀性含氯环境中提供了高度的腐蚀防护。