Continuous nanoscale Al2Fe transition layer strengthened magnesium-steel spot joints

Abstract Cold metal transfer welding was employed to produce Mg to steel spot joints. A continuous and compact plate-like intermetallic Al 2 Fe layer, with a thickness of 100–300 nm, was formed at the interface between solidified AZ61 Mg filler alloy and Zn-coated DP600 steel sheet, resulting in a very high tensile-shear strength of up to 180 MPa. On the contrary, when 100 nm thick, island-type Al 2 Fe was observed at the interface between Mg and uncoated DP600 steel sheet, a much lower joint strength was observed regardless of energy input.