Precipitate-mediated mechanical-corrosion property trade-offs in TIG-welded Al-3.2Cu-1.48Li alloy joint

IF 7.4 1区材料科学 Q1 MATERIALS SCIENCE, MULTIDISCIPLINARY

Corrosion Science Pub Date : 2025-07-16 DOI:10.1016/j.corsci.2025.113197

Caimei Wang , Ziqun Jiang , Yifeng Zhang , Jiqiang Huang , Feng Han , Long Xue , Yu Zhang

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Abstract

The Al-3.2Cu-1.48Li alloy was joined by tungsten inert gas (TIG) welding using 4505 filler wire. The microstructure, mechanical and corrosion properties of the welded joint were systematically investigated. The fusion zone (FZ) exhibited Cu segregation at grain boundaries. Three distinct heat-affected zone (HAZ) regions were identified. HAZ1 exhibited fine T₁ (Al₂CuLi) phase, whereas HAZ2 contained coarsened T₁ with discontinuous θ' (Al₂Cu) phase at grain boundaries. HAZ3 exhibited high density of nanoscale T₁ phase. Microhardness variations correlated strongly with precipitate distributions. HAZ showed hardness fluctuations corresponding to precipitate evolution. FZ softening (77.8 % of base metal (BM) hardness) was inevitable but minimized due to θ' phase strengthening. Tensile fractures consistently initiated at FZ boundaries due to porosity formation in these regions. Intergranular corrosion (IGC) and exfoliation corrosion are used to investigate the corrosion properties of different areas in the welded joint. HAZ3 suffered (the lowest Volta potential) severe IGC due to micro-galvanic effects between T₁ precipitates and Al matrix, and macro-galvanic coupling with other regions. HAZ2 demonstrated reduced IGC sensitivity due to coarse grain boundary precipitates. FZ exhibited superior corrosion resistance due to the cathodic protection from its highest Volta potential. BM and HAZ1 maintained superior corrosion resistance.

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tig焊接Al-3.2Cu-1.48Li合金接头中沉淀介导的机械腐蚀性能权衡

采用4505焊丝对Al-3.2Cu-1.48Li合金进行钨极惰性气体（TIG）焊接。系统地研究了焊接接头的显微组织、力学性能和腐蚀性能。熔合区（FZ）在晶界处表现出Cu偏析。确定了三个不同的热影响区（HAZ）。HAZ1为细T1 （Al2CuLi）相，HAZ2为粗T1，晶界处为不连续的θ′（Al2Cu）相。HAZ3表现出高密度的纳米级T1相。显微硬度变化与析出相分布密切相关。HAZ显示硬度波动与析出相的演化相对应。FZ软化（占母材（BM）硬度的77.8% %）是不可避免的，但由于θ′相强化而使其最小化。由于这些区域的孔隙形成，拉伸裂缝始终在FZ边界处开始。采用晶间腐蚀（IGC）和剥落腐蚀研究了焊接接头不同部位的腐蚀性能。由于T1析出相与Al基体之间的微电效应以及与其他区域的宏观电耦合，HAZ3发生了严重的IGC（最低伏特电位）。由于粗大的晶界沉淀，HAZ2表现出IGC敏感性降低。FZ表现出优异的耐腐蚀性能，这是由于其最高伏特电位的阴极保护。BM和HAZ1保持了优异的耐腐蚀性。

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来源期刊

Corrosion Science 工程技术-材料科学：综合

CiteScore

13.60

自引率

18.10%

发文量

763

审稿时长

46 days

期刊介绍： Corrosion occurrence and its practical control encompass a vast array of scientific knowledge. Corrosion Science endeavors to serve as the conduit for the exchange of ideas, developments, and research across all facets of this field, encompassing both metallic and non-metallic corrosion. The scope of this international journal is broad and inclusive. Published papers span from highly theoretical inquiries to essentially practical applications, covering diverse areas such as high-temperature oxidation, passivity, anodic oxidation, biochemical corrosion, stress corrosion cracking, and corrosion control mechanisms and methodologies. This journal publishes original papers and critical reviews across the spectrum of pure and applied corrosion, material degradation, and surface science and engineering. It serves as a crucial link connecting metallurgists, materials scientists, and researchers investigating corrosion and degradation phenomena. Join us in advancing knowledge and understanding in the vital field of corrosion science.