Effect of Surface States on Joining Mechanisms and Mechanical Properties of Aluminum Alloy (A5052) and Polyethylene Terephthalate (PET) by Dissimilar Friction Spot Welding

Abstract

Abstract:In this research, polyethylene terephthalate (PET), as a high-density thermoplastic sheet, and Aluminum A5052, as a metal with seven distinct surface roughnesses, were joined by friction spot welding (FSW). The effect of A5052's various surface states on the welding joining mechanism and mechanical properties were investigated. Friction spot welding was successfully applied for the dissimilar joining of PET thermoplastics and aluminum alloy A5052. During FSW, the PET near the joining interface softened, partially melted and adhered to the A5052 joining surface. The melted PET evaporated to form bubbles near the joining interface and cooled, forming hollows. The bubbles have two opposite effects: its presence at the joining interface prevent PET from contacting with A5052, while bubbles or hollows are crack origins that induce crack paths which degrade the joining strength. On the other hand, the bubbles' flow pushed the softened PET into irregularities on the roughened surface to form mechanical interlocking, which significantly improved the strength. The tensile-shear failure load for an as-received surface (0.31 µm R a ) specimen was about 0.4-0.8 kN while that for the treated surface (>0.31 µm R a ) specimen was about 4.8-5.2 kN.

Synthesis of Y2O3 films on an aluminum alloy substrate using flame‐spray apparatus with a H2‐O2 flame

“…In contrast, this diffusion was not observed in the as‐synthesized and annealed films at 400 and 500°C for 1 hour. The melting point of A5052 is 607‐649°C . These results indicate that the synthesized Y 2 O 3 films improve the heat resistance of A5052.…”

“…This large difference in the thermal expansion between the deposited films and the substrates introduces delamination, peeling, and deformation in deposited films. In the cyclic thermal tests, the samples were heated close to the melting point of the A5052 substrate (607‐649°C) . Hence, the Y 2 O 3 films synthesized on A5052 form a ceramic‐metal joining with strong adhesion and thermal shock properties.…”

A Comprehensive Review on Optimal Welding Conditions for Friction Stir Welding of Thermoplastic Polymers and Their Composites

“…Also, there are studies available on the development of thermoplastic-metallic hybrid welds. They include thermoplastic-metallic hybrid welds like PMMA-Cu [80], PP-Mg [81], PMMA-AA5058 Al alloy [82], PP-AA5052 Al alloy [83], and PET-A5052 Al alloy [84]. Other related studies include thermoplastic composite-metallic hybrid welds like CF-PPS/AA6181 Al alloy [85,86], CF-PPS/AA2024 Al alloy [87,88], and CF-PPS and GF-PPS/AZ31 Mg alloys [89].…”

Experimental investigation of friction stir spot welding of polymer-aluminum alloy weldments

“…Yusof et al 17 studied the joining of polyethylene terephthalate (PET) as a high-density thermoplastic sheet and AA5052 aluminum sheets by friction spot welding (FSW) process. During the FSW process, the PET near the joining interface softened, partially melted, and adhered to the A5052 joining surface.…”