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© 2021 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (https://creativecommons.org/licenses/by/4.0/). Notwithstanding the ProQuest Terms and Conditions, you may use this content in accordance with the terms of the License.

Abstract

The local dry underwater laser welding of cp-Ti, with air as an assisting gas, and in a simulated underwater facility was researched, aiming to find a viable and economical method for repairing titanium alloy underwater vehicles in situ in the future. Macro-morphology, microstructure, and microhardness of the cp-Ti laser welds, as a function of welding parameters, were experimentally characterized. The oxidation and hardening behaviors of the welds were also studied in detail. It was found that local dry underwater laser welding with air assisted blowing is feasible for obtaining a complete and glossy weld. Compared with a weld in atmosphere, the cross-section morphology of the weld was almost unaffected by the special underwater welding environment. The weld presented a three-layer structure. High temperature and high pressure water vapor and local blowing are the direct causes of weld oxidation, and porosity defects further aggravate the oxidation behavior. The oxygen-enriched areas were mostly concentrated in the top area of the weld center and near the fusion zone, because of the higher number of grain boundaries and phase boundaries. In addition, the partial oxidation caused by local blowing and water vapor atmosphere, and also the higher strength acicular martensite caused by the rapid cooling effect of water, will lead to weld hardening. However, adjusting the welding process parameters, such as increasing the welding speed, can effectively reduce the microhardness of the weld. Our findings can provide an understanding of the influence of water environment on underwater laser welding, and verify the feasibility of a more economical method for the in situ repair of large underwater facilities.

Details

Title
Underwater Laser Welding of Pure Ti: Oxidation and Hardening Behaviors
Author
Luo, Manlelan 1 ; Wei, Pengyu 2 ; Li, Quanhong 1 ; Hu, Renzhi 1 ; Huang, Anguo 1   VIAFID ORCID Logo  ; Pang, Shengyong 1 

 State Key Laboratory of Materials Processing and Die & Mould Technology, Huazhong University of Science and Technology, Wuhan 430074, China; [email protected] (M.L.); [email protected] (Q.L.); [email protected] (R.H.); [email protected] (A.H.) 
 China Ship Scientific Research Center, Wuxi 214082, China 
First page
610
Publication year
2021
Publication date
2021
Publisher
MDPI AG
e-ISSN
20754701
Source type
Scholarly Journal
Language of publication
English
ProQuest document ID
2530184531
Copyright
© 2021 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (https://creativecommons.org/licenses/by/4.0/). Notwithstanding the ProQuest Terms and Conditions, you may use this content in accordance with the terms of the License.