Interfacial microstructures and infiltrated cracks in tin bronze/steel bimetallic materials fabricated by arc cladding.

Tin bronze was cladded on bare steel and nickel-plated steel to fabricate the tin bronze/steel bimetallic materials. The interfacial microstructures and infiltrated cracks in the bimetallic materials were investigated. As the tin bronze was cladded on the bare steel, metallurgical bonding was achieved, and a transition layer with BCC-Fe structure was generated at the tin bronze/steel interface. Infiltrated cracks originated from the interface and propagated into the interior of the steel along the grain boundaries. The main infiltrated crack had branch infiltrated cracks and most of the infiltrated cracks were less than 100 μm. The composition of infiltrated crack was similar to the tin bronze layer, and the infiltrated crack was composed of α-Cu (Sn) phase and δ-Cu41Sn11 phase. The infiltrated cracks could not deform synchronously with the steel matrix, and infiltrated cracks could evolve into macro cracks under lower stress and strain during the in situ tensile experiment. Cracking occurred not only in the boundary between the tin bronze and steel but also occurred in the interior of the tin bronze. Two kinds of fracture zone existed in the fracture including the ductile fracture zone and brittle fracture zone. As the tin bronze was cladded on the nickel-plated steel, a transition layer with BCC-Fe structure was also generated between the tin bronze and steel. Nickel was enriched at the interface and grain boundaries. The infiltrated cracks were eliminated. The nickel-segregated grain boundary could not evolve into macro crack during the in situ tensile process. [ABSTRACT FROM AUTHOR]