Investigation of Interface Characteristics in Duplex Stainless Steel/Low‐Carbon Steel Bimetallic Composites

In this study, the microstructure, elemental distribution, and bonding characteristics of duplex stainless steel/low‐carbon steel (2205/AH36) bimetallic composites are analyzed using electron backscatter diffraction and transmission electron microscopy. The results reveal that the matrix AH36 steel possesses a larger grain size, while the composite layer of 2205 steel features smaller grains and a higher density of recrystallized equiaxed grains. The distribution of C and Mn across both sides of the interface is uniform, whereas the concentration gradients of Cr and Ni are consistent with the phase characteristics of the duplex stainless steel. The AH36 steel matrix exhibits a ferritic microstructure. The 2205 steel layer consists of plate‐like austenite and ferrite phases, along with twin martensite and high‐density faulted austenite. Oxide layers are observed at some regions of the interface, and oxide types are amorphous Si 2 MnO 4 and Al 2 MnO 4 . The kernel average misorientation and other data indicate a higher propensity for slip on both the austenitic side of the 2205 steel and the AH36 steel. The lattice at the interface demonstrates a high degree of matching, indicating that the composite layer has been successfully bonded through phase transformation and elemental diffusion.