Mechanical and microstructural characterization of aluminium micro-pins realized by cold metal transfer

Author:

Schneider-Bröskamp Christian1ORCID,Schnall Martin,Birgmann Alois,Ucsnik Stephan

Affiliation:

1. LKR Leichtmetallkompetenzzentrum Ranshofen GmbH

Abstract

Abstract Advanced and reliable joining technologies for ultra-light weight structures combining aluminium with carbon fibre reinforced plastics (CFRP) are of great interest for aerospace industries. The combination of superior mechanical properties and low density offer a wide range of possible application. The European collaborative research project ADALFIC (Advanced Aluminium Fittings in CFRP tubes) focuses on the design, analysis, manufacturing and testing of ultra-lightweight CFRP tubes with integrated aluminium end fittings. These aluminium end fittings are equipped with very small, minimum-mass, spike-head pins realized by Fronius' cold-metal-transfer (CMT) Print welding technology. These pins are optimized for form-locked joints between aluminium and CFRP components. In this work the aluminium pins are characterized on a macroscopic and microscopic level using light optical microscopy and hardness testing. To evaluate the behavior of the pins under mode II load conditions a new shear testing method for pins was developed and implemented. With this test equipment the maximum shear force and ultimate shear strength of individual pins was measured at different temperatures and heat treatment conditions. The failure modes and fracture surfaces were analyzed via scanning electron microscopy. The results demonstrate that CMT aluminium pins are a viable, flexible and lightweight option for form-locked aluminium-CFRP joints.

Publisher

Research Square Platform LLC

Reference36 articles.

1. Zhang, Guotao and Zhao, Hang and Xu, Xianghe and Qiu, Guohua and Li, Yongbing and Lin, Zhongqin (2019) {Metallic bump assisted resistance spot welding (MBaRSW) of AA6061-T6 and bare DP590: Part I-printing of metallic bump}. Journal of Manufacturing Processes 44: 427--434 https://doi.org/10.1016/j.jmapro.2019.05.042, Elsevier Ltd, aug, Bond strength,Dissimilar materials joining,Metallic bump printing,Resistance spot welding, 15266125, :C$$\backslash$$:/Users/SchneiderC/AppData/Local/Mendeley Ltd./Mendeley Desktop/Downloaded/Zhang et al. - 2019 - Metallic bump assisted resistance spot welding (MBaRSW) of AA6061-T6 and bare DP590 Part I-printing of metallic bu.pdf:pdf, A novel joining method, i.e., metallic bump assisted resistance spot welding (MBaRSW) was proposed, in which, a third-party aluminum metallic bump was printed on either aluminum alloy or steel sheet through modifying the Fronius cold metal transfer (CMT) pin process, and then a resistance spot weld was made via the bump to solve the problems of low joint strength and severe weld thinning in conventional Al/steel resistance spot welds. This two-part paper aims at investigating the mechanism of the novel RSW process. In this part, Fronius CMT pin process was first investigated to examine its control mechanism on pin-like or bump-like morphology of products, and then an exclusive bump printing process was developed. Results showed that due to better wettability the bumps printed on Al substrate were bigger, shorter and much stronger than that on steel substrate in which intermetallic compound (IMC) layer formed along bump/steel interface. The study laid a foundation for development of the novel Al-steel MBaRSW process.

2. Hauser, Tobias and Reisch, Raven T. and Breese, Philipp P. and Lutz, Benjamin S. and Pantano, Matteo and Nalam, Yogesh and Bela, Katharina and Kamps, Tobias and Volpp, Joerg and Kaplan, Alexander F.H. (2021) {Porosity in wire arc additive manufacturing of aluminium alloys}. Additive Manufacturing 41: 101993 https://doi.org/10.1016/j.addma.2021.101993, Elsevier B.V., may, Anomaly,Computer vision,Monitoring,Robot-based,WAAM, 22148604, :C$$\backslash$$:/Users/SchneiderC/AppData/Local/Mendeley Ltd./Mendeley Desktop/Downloaded/Hauser et al. - 2021 - Porosity in wire arc additive manufacturing of aluminium alloys.pdf:pdf, Wire Arc Additive Manufacturing is a near-net-shape processing technology which allows cost-effective manufacturing of large and customized metal parts. Processing of aluminium in Wire Arc Additive Manufacturing is quite challenging, especially in terms of porosity. In the present work, pore behaviour in Wire Arc Additive Manufacturing of AW4043/AlSi5(wt{%}) was investigated and a post-process monitoring approach was developed. It has been observed that as the shielding gas flow rate increases, the porosity in aluminium parts also increases due to the rapid solidification of the melt pool by forced convection. The higher convection rate seems to limit the escape of gas inclusions. Furthermore, gas inclusions escaping from the melt pool leave cavities on the surface of each deposited layer. Process camera imaging is used to monitor these cavities to acquire information about the porosity in the part. The observations were supported by Computational Fluid Dynamics simulations which show that the gas flow rate correlates with the porosity in aluminium parts manufactured by Wire Arc Additive Manufacturing. Since a lower gas flow rate leads to reduced convective cooling, the melt pool remains liquid for a longer period allowing pores to escape for a longer period and thus reducing porosity. Based on these investigations, a monitoring approach is presented.

3. Klein, Thomas and Schnall, Martin and Gomes, Bianca and Warczok, Piotr and Fleischhacker, Dominik and Morais, Paulo J. (2021) {Wire-arc additive manufacturing of a novel high-performance Al-Zn-Mg-Cu alloy: Processing, characterization and feasibility demonstration}. Additive Manufacturing 37(July 2020): 101663 https://doi.org/10.1016/j.addma.2020.101663, https://doi.org/10.1016/j.addma.2020.101663, Elsevier B.V., Heat treatment,High-performance aluminum alloys,Mechanical properties,Microstructure evolution,Wire-arc additive manufacturing, 22148604, :H$$\backslash$$:/Literatur/Mendeley//Klein et al. - 2021 - Wire-arc additive manufacturing of a novel high-performance Al-Zn-Mg-Cu alloy Processing, characterization and fea.pdf:pdf, Wire-arc additive manufacturing (WAAM) is a feasible technology for manufacturing of metallic components of medium complexity with a high deposition rate. Manufacturing of aluminum alloys for e.g. structural components of the aero plane fuselage by this technology has been impeded by the unavailability of high-performance alloys with good processability and low susceptibility to hot cracking. Therefore, a novel alloy system has been developed based on the Al-Zn-Mg-Cu system and successfully processed by WAAM without the occurrence of any hot cracks. Heat treatment strategies were developed allowing for optimum mechanical properties. A homogeneous grain structure was observed with few elongated grains. Upon heat treatment, the formation of T phases was verified with a precipitate size in the range of {\ {}}10 nm. These are responsible for the observed pronounced age-hardening response of this alloy. An isotropic proof stress of up to {\ {}}340 MPa and a fracture strain of up to {\ {}}11{%} are evidence of the high quality of the WAAM deposited material allowing for an extended use of these alloys for advanced applications. Finally, the applicability and processability of the alloy was proven by fabrication of a motorcycle piston.

4. Ucsnik, S and Schnall, M and Birgmann, A (2021) {Load transfer behaviour of ultra-light-weight CFRP-metal struts under elevated and cryogenic working temperatures}. online, Euromat

5. Kirth, Rudolf and Ebel, Christoph (2012) {ARRANGEMENT FOR CONNECTING AN ELONGATE ELEMENT TO A FURTHER COMPONENT}. EP2162634 https://lens.org/074-679-443-516-099, Granted Patent

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