Friction stir alloying of AZ61 and mild steel with Al-CNT additive

The friction stir alloying (FSA) procedure successfully produced dissimilar joints between AZ61 magnesium alloy and mild steel with Al-CNT additions. Before welding, Al-CNT additives were placed in a gap between the AZ61 and steel specimens. The experimentation was performed using different welding speeds while tool rotational speed was kept constant for varying weight percentages of carbon nanotubes (CNT) in Al powder. The influence of additives and welding speed on tensile strength and characterisation across the welding interface was studied. Tensile strength of joint with 3% CNT improved up to 222 MPa. Al-rich intermetallic compounds were found at the welding contact, while the formation of Al2MgC2 carbide was detected, which contributed to CNT strengthening effects all to improved welding strength.