Friction Stir Spot Welding-Brazing of Al and Hot-Dip Aluminized Ti Alloy with Zn Interlayer

Xingwen Zhou,Shuhan Li,Yongde Huang,Yuhua Chen,Kun Hao,Peng Peng

doi:10.3390/met8110922

Abstract

Friction stir spot welding (FSSW) of Al to Ti alloys has broad applications in the aerospace and automobile industries, while its narrow joining area limits the improvement of mechanical properties of the joint. In the current study, an Al-coating was prepared on Ti6Al4V alloy by hot-dipping prior to joining, then a Zn interlayer was used during friction stir joining of as-coated Ti alloy to the 2014-Al alloy in a lap configuration to introduce a brazing zone out of the stir zone to increase the joining area. The microstructure of the joint was investigated, and the joint strength was compared with the traditional FSSW joint to confirm the advantages of this new process. Because of the increase of the joining area, the maximum fracture load of such joint is 110% higher than that of the traditional FSSW joint under the same welding parameters. The fracture load of these joints depends on the joining width, including the width of solid-state bonding region in stir zone and brazing region out of stir zone.

Highlights

Lightweight hybrid structures have attracted increasing attention in the aerospace and automobile industries to enhance performance efficiency as well as to reduce environmental impact [1,2,3,4]
The Zn interlayer and Al coating have no significant influence in the stir zone of the friction stir spot welding (FSSW)-B joint
This study provides an improved friction stir spot joining process for the joining of Al and

Summary

Introduction

Lightweight hybrid structures have attracted increasing attention in the aerospace and automobile industries to enhance performance efficiency as well as to reduce environmental impact [1,2,3,4]. In this context, the dissimilar joining of aluminum (Al) and titanium (Ti) alloys has been widely used in the manufacturing of lightweight hybrid structures [4,5,6]. Many reports on FSSW of similar or dissimilar metals mainly focus on the process, microstructural characteristics, and numerical simulations to Metals 2018, 8, 922; doi:10.3390/met8110922 www.mdpi.com/journal/metals

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