Influence of the kissing bond defect on the fatigue life in friction stir welds of 2024 aluminium alloy

AbstractMechanical alloying can be carried out by a method known as friction stir processing, whereby solid Zn particles in a solution are distributed onto an aluminium alloy plate. The aim of this study was to determine the effects of a volume of Zn particles on the mechanical and physical properties of aluminium 1xxx alloy that had been subjected to friction stir processing. The specimens were plates composed of 1xxx series aluminium. A groove, measuring 12 mm in diameter, was pierced to various depths, and the Zn particles in these containers were then subjected to friction stir processing using a pin-less tool with a diameter of 15 mm. The results showed that the highest hardness was found in the uppermost layer of the workpiece, and this gradually decreased with thickness. An increase in the amount of Zn particles caused an increase in material hardness. The highest hardness of 87.1 HV in the friction stir-processed AA1100 was obtained at the highest volume of Zn compared to the hardness of 44.5 HV, which was obtained for the specimen without the addition of Zn.

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Fatigue Modeling and Numerical Analysis of Re-Filling Probe Hole of Friction Stir Spot Welded Joints in Aluminum Alloys

Materials ◽

10.3390/ma14092171 ◽

2021 ◽

Vol 14 (9) ◽

pp. 2171

Author(s):

Armin Yousefi ◽

Ahmad Serjouei ◽

Reza Hedayati ◽

Mahdi Bodaghi

Keyword(s):

Experimental Data ◽

Tensile Strength ◽

Fatigue Life ◽

Fatigue Strength ◽

Fatigue Behavior ◽

Element Model ◽

Plastic Strain Amplitude ◽

Friction Stir ◽

Probe Hole ◽

Good Agreement

In the present study, the fatigue behavior and tensile strength of A6061-T4 aluminum alloy, joined by friction stir spot welding (FSSW), are numerically investigated. The 3D finite element model (FEM) is used to analyze the FSSW joint by means of Abaqus software. The tensile strength is determined for FSSW joints with both a probe hole and a refilled probe hole. In order to calculate the fatigue life of FSSW joints, the hysteresis loop is first determined, and then the plastic strain amplitude is calculated. Finally, by using the Coffin-Manson equation, fatigue life is predicted. The results were verified against available experimental data from other literature, and a good agreement was observed between the FEM results and experimental data. The results showed that the joint’s tensile strength without a probe hole (refilled hole) is higher than the joint with a probe hole. Therefore, re-filling the probe hole is an effective method for structures jointed by FSSW subjected to a static load. The fatigue strength of the joint with a re-filled probe hole was nearly the same as the structure with a probe hole at low applied loads. Additionally, at a high applied load, the fatigue strength of joints with a refilled probe hole was slightly lower than the joint with a probe hole.

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Mechanical and Microstructural Characterization of Friction Stir Welded SiC and B4C Reinforced Aluminium Alloy AA6061 Metal Matrix Composites

Materials ◽

10.3390/ma14113110 ◽

2021 ◽

Vol 14 (11) ◽

pp. 3110

Author(s):

Kaveripakkam Suban Ashraff Ali ◽

Vinayagam Mohanavel ◽

Subbiah Arungalai Vendan ◽

Manickam Ravichandran ◽

Anshul Yadav ◽

...

Keyword(s):

Wear Rate ◽

Aluminium Alloy ◽

Metal Matrix Composites ◽

Metal Matrix ◽

Weld Zone ◽

Base Material ◽

Matrix Composites ◽

Wear Properties ◽

Friction Stir ◽

Behavioural Aspects

This study focuses on the properties and process parameters dictating behavioural aspects of friction stir welded Aluminium Alloy AA6061 metal matrix composites reinforced with varying percentages of SiC and B4C. The joint properties in terms of mechanical strength, microstructural integrity and quality were examined. The weld reveals grain refinement and uniform distribution of reinforced particles in the joint region leading to improved strength compared to other joints of varying base material compositions. The tensile properties of the friction stir welded Al-MMCs improved after reinforcement with SiC and B4C. The maximum ultimate tensile stress was around 172.8 ± 1.9 MPa for composite with 10% SiC and 3% B4C reinforcement. The percentage elongation decreased as the percentage of SiC decreases and B4C increases. The hardness of the Al-MMCs improved considerably by adding reinforcement and subsequent thermal action during the FSW process, indicating an optimal increase as it eliminates brittleness. It was seen that higher SiC content contributes to higher strength, improved wear properties and hardness. The wear rate was as high as 12 ± 0.9 g/s for 10% SiC reinforcement and 30 N load. The wear rate reduced for lower values of load and increased with B4C reinforcement. The microstructural examination at the joints reveals the flow of plasticized metal from advancing to the retreating side. The formation of onion rings in the weld zone was due to the cylindrical FSW rotating tool material impression during the stirring action. Alterations in chemical properties are negligible, thereby retaining the original characteristics of the materials post welding. No major cracks or pores were observed during the non-destructive testing process that established good quality of the weld. The results are indicated improvement in mechanical and microstructural properties of the weld.

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Influence of Impact-Oscillatory Loading on Fatigue Life of Aluminium Alloy 2024-T351

Iranian Journal of Science and Technology Transactions of Mechanical Engineering ◽

10.1007/s40997-021-00443-3 ◽

2021 ◽

Author(s):

Mykola Chausov ◽

Elena Zasimchuk ◽

Pavlo Maruschak ◽

Oleg Khyzhun ◽

Andrii Pylypenko ◽

...

Keyword(s):

Fatigue Life ◽

Aluminium Alloy

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