The experimental study of CFRP interlayer of dissimilar joint AA7075-T651/Ti-6Al-4V alloys by friction stir spot welding on mechanical and microstructural properties

• Published in: Nanotechnology reviews (Berlin) 2021-01, Vol.10 (1), p.401-413
• Main Authors: Nasir, Tauqir, Kalaf, Omer, Asmael, Mohammed, Zeeshan, Qasim, Safaei, Babak, Hussain, Ghulam, Motallebzadeh, Amir
• Format: Article
• Language: English
• Subjects: Addition polymerization; Alloys; aluminum alloys; Aluminum base alloys; Carbon fiber reinforced plastics; Carbon fiber reinforcement; carbon fiber-reinforced polymer; Dissimilar material joining; Dissimilar metals; Dwell time; Fiber reinforced polymers; Friction; friction stir spot welding; Friction stir welding; Hardness; interlayer; Interlayers; Intermetallic compounds; Mechanical properties; Microhardness; Polymers; Scanning electron microscopy; Shear; Spot welding; titanium alloys; Titanium aluminides; Titanium base alloys; Titanium compounds; Welded joints; Welding; Welding parameters
• ISSN: 2191-9097; 2191-9089; 2191-9097
• DOI: 10.1515/ntrev-2021-0032

The present study focused on two dissimilar metal alloys: AA7075-T651 and Ti-6Al-4V alloys with additional carbon fiber-reinforced polymer (CFRP) as an interlayer were welded together by friction stir spot welding (FSSW). The effect of welding parameters (rotational speed and dwell time) and carbon fiber-reinforced polymer on mechanical and microstructural properties of a weld joint was investigated. The obtained results explore the parametric effects on mechanical properties of the weld joint. The maximum tensile shear load 2597.8 N was achieved at the rotational speed of 2,000 rpm and dwell time of 10 s. While at the same rotational speed, 54.7% reduction in the tensile shear load was attained at shorter dwell time of 5 s. Therefore, dwell time plays an important role in the tensile shear load of a weld joint. The scanning electron microscope (SEM-EDS) results show the formation of intermetallic compound of Ti Al and Ti-Al-C that significantly affect the mechanical and microstructural properties of the weld joint. Moreover, the effect of the rotational speed on micro-hardness was found at significant than dwell time. The micro-hardness of the weld joint increase by 18.90% in the keyhole rather than the stir zone and the thermomechanical affected zone, which might be due to the presence of ternary (Ti-Al-C) intermetallic compound.