Investigation of the tensile strength of the CMT and PCMT joints of AA8011 aluminum alloy

Abstract

The advanced variant of gas metal arc welding (GMAW) known as cold metal transfer (CMT) developed by Fronius in Austria is used to overcome heat-input- and fusion-related issues such as porosity and cracking in welding of AA8011-H18 alloy sheets. AA8011-H18 alloy sheets 3 mm thick were welded using normal CMT-GMAW and pulsed CMT (PCMT)-GMAW processes. The microstructure of the weld metal and heat-affected zone was analyzed using an optical microscope. The tensile properties and hardness of joints were evaluated and compared. The results revealed that the PCMT-GMAW joints showed 26.45, 48.97 and 40.42% improvements in tensile strength, yield strength and elongation, respectively, compared with CMT-GMAW joints. The superior tensile performance of PCMT-GMAW joints compared with that of CMT-GMAW joints is due to the current pulsing effects along with the wire retraction mechanism, which aids in reducing the heat input and controlled droplet transfer.