as shown in Fig. 3a, the fracture a

as shown in Fig. 3a, the fracture at the upper part of the joint with the 0 mm offset happened in the weld seam of Mg alloy, while the fracture path at the lower part was along the Mg/Fe interface. This fracture characteristic suggested that the bonding of the Mg/Fe interface was more reliable at the upper part than that at the lower part. However, the fracture of the joint with the 0.2 mm offset, shown in Fig. 3b, just happened in the weld seam of Mg alloy instead of the Mg/Fe interface, indicating the intimate and reliable bonding of the interface.rial.