Effects Of Si Addition On The Growth Behavior Of Intermetallic Compound Layer At Aluminum/steel Rolling Interface

Since aluminum/steel laminated composites have wear resistance, good mechanical properties, low density, high electrical conductivity and thermal conductivity, they have been widely used in the automobile industry, aerospace, mechanical industry, chemical industry, daily life, et al. The brittle intermetallic phases will form when the material is produced or used at high temperature. In this paper, Al-Si alloy/low-carbon steel clad plates was produced by cold-rolling. Under different annealing conditions, Silicon’s effect on the formation of the intermetallic compound (IMC) in the interface was investigated by using a combination of optical microscopy(OM), scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy(EDS) and X-ray diffraction (XRD).The main conclusions are as follows:(1)The relationship between the critical forming temperature of IMC and content of Si was investigated. With the increase of Si content, the critical temperature rises, and then falls. When Si addition reaches0.67wt.%, the critical temperature is615℃(2)Si addition changes the order of phase formation in Fe-Al binary system. When content of Si is less than0.91wt.%,0(FeAl3) is the first phase formed during annealing. With the elongation of annealing time, η(Fe2Al5) is formed. When content of Si is from1.62to2.25wt.%, τ6(Al8Fe2Si) is the first phase formed during annealing. With the elongation of annealing time, τ5(A145FeSi) is formed, and η(Fe2Al5) is last formed. When the annealing time is enough long, the structure of IMC is τ5(Al4.5FeSi)-η(Fe2Al5).(3)The addition of Si to Aluminum was found to accelerate the IMC growth under annealing condition. At615℃, the growth constant(k) of Al-1.62wt.%Si/steel clad plate is7.3426×10-12m2/s; while the constant(k) of pure-Al/steel is9.6833×10-14m2/s.(4)The growth activation energy (Q) for the growth of the IMC is calculated. When content of Si is0.10wt.%,0.67wt.%,0.91wt.%and 1.62wt.%, the growth activation energy (Q) is215.85KJ/mol,335.58K J/mol,289.56KJ/mol, and203.13KJ/mol, respectively. When the addition of Si is between0.67and0.91wt.%, the growth activation energy of IMC increases, which restrains the growth of IMC.