PSI- Issue 9

Mohammad Jameel Zedan et al. / Procedia Structural Integrity 9 (2018) 37–46 Mohammad Jameel Zedan, et al. / Structural Integrity Procedia 00 (2018) 000–000

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 The hole on aluminum plate side provides a passage for the molten metal to be inside this hole. Otherwise, the molten metal (expulsion) will spread between the dissimilar alloys, which causes outward pressure between them and forms a thin layer that prevents welding process 3.2. Tensile force of RSW joint Figures 3 and 4 show the relationship between the RSW factors and fracture load. The values of the tensile load increase significantly when the electrode force increases from 1500 N to 2400 N, welding current from 11.25 to 14.25 KA, and welding time from 25 to 40 Cycle. The results also were presented in previous studies for RSW of similar metals, see Refs. (Al-Mukhtar 2015, 2016; A. Al-Mukhtar and Doos 2013; A. M. Al-Mukhtar and Doos 2013; Daws et al. 2003). The pullout failure mode was noticed in current work and no interfacial failure mode. Because the hole provides a suitable cavity for desired weld nugget. Failure occurs around HAZ on the aluminum alloy side, see Fig. 5. The fracture from HAZ in spot weld is predominated due to the defect, and lower fracture toughness (Al-Mukhtar 2016, 2015; A. M. Al-Mukhtar and Doos 2013). However, the margin of weld like weld toe suffering cracking, and the crack propagated very likely, see Refs (A.M. Al-Mukhtar 2011; A. Al-Mukhtar 2013; A. Al-Mukhtar et al. 2010; A. M. Al-Mukhtar 2013a, 2013b; A. M. Al-Mukhtar et al. 2010; Al-Mukhtar 2015; Al-Mukhtar et al. 2009, 2011; Mukhtar et al. 2009)

Fig. 3. The relationship between electrode force and tensile force, welding currents 14.25 KA.

Fig. 4. The relationship between welding currents and tensile force, electrode force 2400 N.