The effect of thermal frequency and current amplitude on weldability, microstructural evolution and mechanical properties of AA7075 alloy joint in DP-GMAW process

Feasibility and travel speed influence on welding AA7075-T651 using cold wire pulsed gas metal arc welding (Cold Wire-P-GMAW)

“…Table 1) which is a Al-Mg that does not possess the same chemistry of the weld metal, therefore during welding a dilution of the weld metal occurs impairing its mechanical strength. This is consistent with the results obtained by Soltani et al [3] which welded using dual-pulsed gas metal arc welding (DP-GMAW),…”

“…Towards the heat affected zone the hardness increases reaching on average 148.1 HV, for the specimen manufactured using travel speed of 90 cm/min, and 154.6 HV for the specimen manufactured using travel speed of 100 cm/min. This is attributable both to the re ning of grains caused by the welding cycle in the heat affected zone [3]. Moreover, despite the increase in travel speed, the hardness measured at the specimen manufactured with the travel speed of 90 cm/min is not statistically different from the hardness measured in the specimen manufactured with travel speed of 100 cm/min.…”

“…These regions exhibit a tendency for the precipitation of these phases both inside the grains and along their boundaries, often near the junctions. This speci c precipitation behavior contributes to the manifestation of Solidi cation Cracking (SC) within the fusion zone and Liquation Cracking (LC) within the partially melted zone (PMZ) [3,4,20,21].…”

“…However, this alloy is prone to solidi cation and liquation cracking when welded due to its maximum copper concentration of 2 wt.%, which widens the solidi cation temperature and reduces the solidus temperature, thus increasing the tendency towards solidi cation cracking upon cooling [3]. In addition, the partially melted zone (PMZ) adjacent to the fusion line, which is locally melted during welding, is sensitive to liquation cracking due to heating above the eutectic temperature and the presence of precipitates, as AA7075 T-651 is within the solid solubility limit [4].…”

Investigation of the Difference in the Pulse Current in the Double Pulsed Gas Metal Arc Welding of Aluminum Alloys

“…Wu et al [ 14 , 15 ] also analyzed the influence of current phase on weld seam formation and metal transfer behavior under different pulse phases in double-wire DP-GMAW. Soltani et al [ 16 ] studied the effect of thermal frequency and current amplitude on the weldability, microstructural evolution and mechanical properties of AA7075 alloy joints welded by DP-GMAW. Liu et al [ 17 ] believed that increasing the base current amplitude or the thermal frequency of the current effectively enhanced the oscillation of the molten pool in the DP-GMAW of an AA6061-T6 aluminum alloy.…”