Interfacial Bonding Behavior of Stainless Steel/Carbon Steel-Laminated Composites Fabricated by Liquid-Solid Bonding

Liquid-solid (L-S) bonding is a promising technique for preparing laminate metal matrix composites, nevertheless, interfacial heat transfer and microstructure evolution are complicated and strongly affect the bonding behavior. Herein, stainless steel (SS)/carbon steel (CS)-laminated composites are fabricated by L-S bonding method under different conditions. The interfacial heat-transfer behavior and microstructure characteristics are investigated by simulations and experiments, and the bonding mechanism are analyzed. Dramatic heat transfer occurs at the cladding interface and results in a vertical temperature gradient, the substrate temperature sharply increases to the peak value and then decreases with reducing cooling rate. Metallurgical bonding cladding interfaces without oxides are obtained under a melt temperature of 1923 K and substrate-preheating temperatures of 773 and 973 K. During the L-S bonding process, an Fe-O oxide layer covering the substrate forms and then spalls from the substrate due to cracking or decomposition due to intense heat flux during the heating stage. Subsequently, solid diffusion or dissolution diffusion initiates at the fresh surface and forms flat or waved cladding interface, and the diffusion distance of Cr is significantly improved by dissolution diffusion, resulting in strengthened cladding interface zone of the SS/CS-laminated composite.