Fabrication of Aluminum Tubes Filled with Aluminum Alloy Foam by Friction Welding.

Yoshihiko Hangai,Yukiko Nakano,Osamu Kuwazuru,Soichiro Kitahara,Nobuhiro Yoshikawa,Shinji Koyama

doi:10.3390/ma8105373

Yoshihiko Hangai, Yukiko Nakano + Show 4 more

Open Access

https://doi.org/10.3390/ma8105373

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Journal: Materials	Publication Date: Oct 23, 2015
Citations: 16	License type: CC BY 4.0

Affiliation: Kiryu University, Gunma University, University of Fukui

Abstract

Aluminum foam is usually used as the core of composite materials by combining it with dense materials, such as in Al foam core sandwich panels and Al-foam-filled tubes, owing to its low tensile and bending strengths. In this study, all-Al foam-filled tubes consisting of ADC12 Al-Si-Cu die-cast aluminum alloy foam and a dense A1050 commercially pure Al tube with metal bonding were fabricated by friction welding. First, it was found that the ADC12 precursor was firmly bonded throughout the inner wall of the A1050 tube without a gap between the precursor and the tube by friction welding. No deformation of the tube or foaming of the precursor was observed during the friction welding. Next, it was shown that by heat treatment of an ADC12-precursor-bonded A1050 tube, gases generated by the decomposition of the blowing agent expand the softened ADC12 to produce the ADC12 foam interior of the dense A1050 tube. A holding time during the foaming process of approximately tH = 8.5 min with a holding temperature of 948 K was found to be suitable for obtaining a sound ADC12-foam-filled A1050 tube with sufficient foaming, almost uniform pore structures over the entire specimen, and no deformation and minimum reduction in the thickness of the tube.

Highlights

Aluminum foam is lighter than dense aluminum (Al) and exhibits superior energy absorption and sound insulation properties [1,2]; it is expected to be used in components of automobiles and construction materials
The images were reconstructed from cross-sectional X-ray computed tomography (CT) images of the entire specimen using ImageJ image processing software. tin is the tool indentation time from when the tool first came into contact with the surface of the ADC12 precursor
Note that these images do not show the same sample, for example, for the sample with tin = 2 min, a new ADC12 precursor and A1050 tube were prepared, the tool indentation was conducted from tin = 0 min to tin = 2 min

Summary

Introduction

Aluminum foam is lighter than dense aluminum (Al) and exhibits superior energy absorption and sound insulation properties [1,2]; it is expected to be used in components of automobiles and construction materials. A fabrication process for Al-foam-filled dense steel tubes with metal bonding has been developed [19,20] In this process, using a friction-based process such as friction welding [21,22] or friction stir back extrusion [23,24,25,26,27], a solid Al composite in which blowing agent powder is uniformly distributed, called the precursor, is first bonded with a dense steel tube. In a previous study on Al foam core sandwich panels comprising one Al foam core layer and two dense SPCC low-carbon steel face sheet layers, an Fe-Al intermetallic compound layer with a thickness of several tens μm was generated at the interface, the bonding of the interface exhibited higher strength than that of the Al foam itself [17]. The distribution of elemental Si, which only exists in ADC12 Al alloy at a concentration of approximately 10 mass %, was observed by electron probe microanalysis (EPMA)

Results and Discussion

Experimental Section

Conclusions