Stress corrosion crack sensitivity of ultra-thick TC4 titanium alloy electron beam welding joints

被引：0

作者：

Fang W. ^{[1
]}

Xiao T. ^{[2
]}

Zhang Y. ^{[1
]}

Xu W. ^{[1
]}

Yi Y. ^{[1
]}

机构：

[1] Guangdong Provincial Key Laboratory of Advanced Welding Technology, Guangdong Welding Institute, Guangzhou

[2] Institute of Metal Research Chinese Academy of Sciences, Shenyang

来源：

Hanjie Xuebao/Transactions of the China Welding Institution | 2019年 / 40卷 / 12期

关键词：

Electron beam welding; Fracture morphology; Microstructure; Stress corrosion crack; Titanium alloy;

D O I：

10.12073/j.hjxb.2019400324

中图分类号：

学科分类号：

摘要：

Slow strain rate tensile method was adopted to evaluate the stress corrosion crack (SCC) sensitivity of 100 mm ultra-thick TC4 titanium alloy electron beam welded (EBW) joints under artificial seawater. The corrosion mechanism was studied by observing the microstructure and fracture morphology of the joint. The results showed that the base metal have no SCC sensitivity in seawater. However, the upper, middle and lower parts of the weld showed slight SCC sensitivity at room temperature under the condition of strain rate ε=1×10-6 s-1. In seawater, anodic dissolution accursed in the weld metal, which increased the Ti ion concentration in the solution at the crack tip, then, H atoms are evolved and absorbed at the crack tip. The diffused hydrogen then promotes dislocation emission and increases the dislocation density at the α' phase boundaries and in the α' phase. The crack initiation and propagation are results of the accumulation of highly hydrogen. At the same time, hydrogen enhances mobility of dislocations, then the crack propagates at a lower stress level. © 2019, Editorial Board of Transactions of the China Welding Institution, Magazine Agency Welding. All right reserved.

引用

页码：121 / 128

页数：7

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