Fatigue Life Assessment of Refill Friction Stir Spot Welded Alclad 7075-T6 Aluminium Alloy Joints
Refill Friction Stir Spot Welding (RFSSW) shows great potential to be a replacement for single-lap joining techniques such as riveting or resistance spot welding used in the aircraft industry. In this paper, the fatigue behaviour of RFSSW single-lap joints is analysed experimentally in lap-shear spe...
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MDPI AG
2020-05-01
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| Online Access: | https://www.mdpi.com/2075-4701/10/5/633 |
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| author | Andrzej Kubit Mateusz Drabczyk Tomasz Trzepiecinski Wojciech Bochnowski Ľuboš Kaščák Jan Slota |
| author_facet | Andrzej Kubit Mateusz Drabczyk Tomasz Trzepiecinski Wojciech Bochnowski Ľuboš Kaščák Jan Slota |
| author_sort | Andrzej Kubit |
| collection | DOAJ |
| description | Refill Friction Stir Spot Welding (RFSSW) shows great potential to be a replacement for single-lap joining techniques such as riveting or resistance spot welding used in the aircraft industry. In this paper, the fatigue behaviour of RFSSW single-lap joints is analysed experimentally in lap-shear specimens of Alclad 7075-T6 aluminium alloy with different thicknesses, i.e., 0.8 mm and 1.6 mm. The joints were tested under low-cycle and high-cycle fatigue tests. Detailed observations of the fatigue fracture characteristics were conducted using a scanning electron microscope (SEM) with energy dispersive X-ray spectroscopy (EDS). The locations of fatigue failure across the weld, fatigue crack initiation, and propagation behaviour are discussed on the basis of the SEM analysis. The possibility of predicting the propagation of fatigue cracks in RFSSW joints is verified based on Paris’s law. Two fatigue failure modes are observed at different load levels, including shear fracture mode transverse crack growth at high stress-loading conditions and at low load levels, and destruction of the lower sheet due to stretching as a result of low stress-loading conditions. The analysis of SEM micrographs revealed that the presence of aluminium oxides aggravates the inhomogeneity of the material in the weld nugget around its periphery and is a source of crack nucleation. The results of the fatigue crack growth rate predicted by Paris’s law were in good agreement with the experimental results. |
| first_indexed | 2024-03-10T19:52:54Z |
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| institution | Directory Open Access Journal |
| issn | 2075-4701 |
| language | English |
| last_indexed | 2024-03-10T19:52:54Z |
| publishDate | 2020-05-01 |
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| record_format | Article |
| series | Metals |
| spelling | doaj.art-becc2cdb3e13472f90c17019761d5bcb2023-11-20T00:16:05ZengMDPI AGMetals2075-47012020-05-0110563310.3390/met10050633Fatigue Life Assessment of Refill Friction Stir Spot Welded Alclad 7075-T6 Aluminium Alloy JointsAndrzej Kubit0Mateusz Drabczyk1Tomasz Trzepiecinski2Wojciech Bochnowski3Ľuboš Kaščák4Jan Slota5Department of Manufacturing and Production Engineering, Rzeszow University of Technology, al. Powst. Warszawy 8, 35-959 Rzeszów, PolandInstitute of Technology, Faculty of Mathematics and Natural Sciences, University of Rzeszów, al. Rejtana 16c, 35-959 Rzeszow, PolandDepartment of Materials Forming and Processing, Rzeszow University of Technology, al. Powst. Warszawy 8, 35-959 Rzeszów, PolandCentre for Innovative Technologies, University of Rzeszów, ul. Pigonia 1, 35-959 Rzeszów, PolandInstitute of Technology and Material Engineering, Faculty of Mechanical Engineering, Technical University of Košice, Mäsiarska 74, 040 01 Košice, SlovakiaInstitute of Technology and Material Engineering, Faculty of Mechanical Engineering, Technical University of Košice, Mäsiarska 74, 040 01 Košice, SlovakiaRefill Friction Stir Spot Welding (RFSSW) shows great potential to be a replacement for single-lap joining techniques such as riveting or resistance spot welding used in the aircraft industry. In this paper, the fatigue behaviour of RFSSW single-lap joints is analysed experimentally in lap-shear specimens of Alclad 7075-T6 aluminium alloy with different thicknesses, i.e., 0.8 mm and 1.6 mm. The joints were tested under low-cycle and high-cycle fatigue tests. Detailed observations of the fatigue fracture characteristics were conducted using a scanning electron microscope (SEM) with energy dispersive X-ray spectroscopy (EDS). The locations of fatigue failure across the weld, fatigue crack initiation, and propagation behaviour are discussed on the basis of the SEM analysis. The possibility of predicting the propagation of fatigue cracks in RFSSW joints is verified based on Paris’s law. Two fatigue failure modes are observed at different load levels, including shear fracture mode transverse crack growth at high stress-loading conditions and at low load levels, and destruction of the lower sheet due to stretching as a result of low stress-loading conditions. The analysis of SEM micrographs revealed that the presence of aluminium oxides aggravates the inhomogeneity of the material in the weld nugget around its periphery and is a source of crack nucleation. The results of the fatigue crack growth rate predicted by Paris’s law were in good agreement with the experimental results.https://www.mdpi.com/2075-4701/10/5/633aircraft industryaluminium alloyfriction stir spot weldingmechanical engineeringsingle-lap joints |
| spellingShingle | Andrzej Kubit Mateusz Drabczyk Tomasz Trzepiecinski Wojciech Bochnowski Ľuboš Kaščák Jan Slota Fatigue Life Assessment of Refill Friction Stir Spot Welded Alclad 7075-T6 Aluminium Alloy Joints Metals aircraft industry aluminium alloy friction stir spot welding mechanical engineering single-lap joints |
| title | Fatigue Life Assessment of Refill Friction Stir Spot Welded Alclad 7075-T6 Aluminium Alloy Joints |
| title_full | Fatigue Life Assessment of Refill Friction Stir Spot Welded Alclad 7075-T6 Aluminium Alloy Joints |
| title_fullStr | Fatigue Life Assessment of Refill Friction Stir Spot Welded Alclad 7075-T6 Aluminium Alloy Joints |
| title_full_unstemmed | Fatigue Life Assessment of Refill Friction Stir Spot Welded Alclad 7075-T6 Aluminium Alloy Joints |
| title_short | Fatigue Life Assessment of Refill Friction Stir Spot Welded Alclad 7075-T6 Aluminium Alloy Joints |
| title_sort | fatigue life assessment of refill friction stir spot welded alclad 7075 t6 aluminium alloy joints |
| topic | aircraft industry aluminium alloy friction stir spot welding mechanical engineering single-lap joints |
| url | https://www.mdpi.com/2075-4701/10/5/633 |
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