Lap joining of Ti6Al4V titanium alloy by vortex flow-based friction stir welding

IF 4.8 2区材料科学 Q1 MATERIALS SCIENCE, CHARACTERIZATION & TESTING

Materials Characterization Pub Date : 2024-10-18 DOI:10.1016/j.matchar.2024.114462

Wentao Li , Tairui Zhang , Xiaochao Liu , Minghang Cheng , Xianjun Pei , Xincheng Wang , Ping Zhang , Wenwen Sun , Yong Wu , Zhikang Shen , Xin Ma , Zhonghua Ni

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引用次数: 0

Abstract

The current study uses a novel vortex flow-based friction stir lap welding (VFSLW) process to weld 1.4 mm thick Ti6Al4V sheets, trying to replace the diffusion bonding in the superplastic forming/diffusion bonding process. The mechanical properties and joining mechanism of the VFSLW joint were investigated. Good weld formation was obtained at 300–350 rpm and 80 mm/min. No hook defect was formed in the lap interface. The lap joint fractured across the stir zone (SZ) in the top plate under the optimal parameters. The cracks initiated from the oxidation defect, where the oxides on the workpiece surface were involved in the SZ by the vortex during the welding. It suggests that a good argon shield is very important for the VFSLW of titanium alloy. The highest tensile strength reaches ∼890 MPa, up to 95 % of the base material. The formation of an α + β lamellar structure in the SZ is due to the peak welding temperature exceeding the β-transus temperature. In the bonded zone (BZ), a very thin layer with ultrafine α grains was formed by dynamic recrystallization in the α phase field, although its two sides are α + β lamellar structures. This is because of the oxidation on the workpiece surface during the welding process and the O element is a strong α stabilizer.

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通过涡流搅拌摩擦焊搭接 Ti6Al4V 钛合金

本研究采用一种新型涡流搅拌摩擦搭接焊（VFSLW）工艺来焊接 1.4 mm 厚的 Ti6Al4V 板材，试图取代超塑性成形/扩散粘接工艺中的扩散粘接。研究了 VFSLW 接头的机械性能和连接机制。在 300-350 rpm 和 80 mm/min 的转速下，焊缝形成良好。搭接界面没有形成钩状缺陷。在最佳参数下，搭接接头在顶板的搅拌区（SZ）断裂。裂纹源于氧化缺陷，工件表面的氧化物在焊接过程中被涡流卷入了 SZ。这表明良好的氩气保护对钛合金的 VFSLW 非常重要。最高抗拉强度达到 ∼890 MPa，达到母材的 95%。SZ 中形成 α + β 层状结构的原因是峰值焊接温度超过了 β 传递温度。在结合区 (BZ) 中，虽然其两侧为 α + β 层状结构，但在α 相场中通过动态再结晶形成了具有超细α 晶粒的极薄层。这是因为在焊接过程中工件表面会发生氧化，而 O 元素是一种很强的 α 稳定剂。

本文章由计算机程序翻译，如有差异，请以英文原文为准。

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来源期刊

Materials Characterization 工程技术-材料科学：表征与测试

CiteScore

7.60

自引率

8.50%

发文量

746

审稿时长

36 days

期刊介绍： Materials Characterization features original articles and state-of-the-art reviews on theoretical and practical aspects of the structure and behaviour of materials. The Journal focuses on all characterization techniques, including all forms of microscopy (light, electron, acoustic, etc.,) and analysis (especially microanalysis and surface analytical techniques). Developments in both this wide range of techniques and their application to the quantification of the microstructure of materials are essential facets of the Journal. The Journal provides the Materials Scientist/Engineer with up-to-date information on many types of materials with an underlying theme of explaining the behavior of materials using novel approaches. Materials covered by the journal include: Metals & Alloys Ceramics Nanomaterials Biomedical materials Optical materials Composites Natural Materials.