Study On The Casting Process And The Interfacial Microstructure And Mechanical Properties Of Ti/Al Clad Plate

Ti/Al clad plate have nice corrosion resistance,biological non-toxic of Ti alloy,but also have nice thermal conductivity,light weight of A1 alloy,Ti/Al have been widely used in marine engineering,shipping and other fields.At present,people generally use the rolling clad and explosive clad method for the production of Ti/Al clad plate.However,the explosive compounding method has the disadvantage of low production efficiency and rolling compounding method,which has the disadvantage of smaller thickness of the product.Compared with the rolling compounding method and explosive compounding method,the casting compounding method has higher production efficiency and wide applicable thickness,and can be applied to product different thickness of the plate.In this study,the effect of pouring temperature of molten aluminum and the cooling strength of solidification process on the microstructure and interfacial properties of Ti/Al were investigated by scanning electron microscopy,EDS and XRD.By changing the composition of aluminum alloy,studied the effects of Zn and Si on the microstructure and properties of Ti/Al cast clad interface.Get the following conclusion:(1)With the increase of pouring temperature,the intermetallic compounds distribute continuously along the Ti/Al clad interface and the more uniform the thickness,the lower the bonding strength of the clad interface.When the pouring temperature rose from 700℃ to 800℃,the bonding strength of clad interface decreased from 43.3MPa to 21.3MPa.(2)The cooling strength in the cast clad significantly affects the morphology of the Ti/Al clad interface and the thickness of the intermetallic compound layer.When the pouring temperature is 740℃,the Ti/Al intermetallic compound is continuous and uniform in thickness and has a thickness of 0.32p.m.When air cooling is applied,the intermetallic compounds distribute discontinuously along the clad interface and the thickness is very thin uniform,the thickness of 0.49μm.(3)With the increase of diffusion annealing temperature and holding time,the thickness of intermetallic compound layer at Ti/Al interface is increasing.After 550℃×2h diffusion annealing it is 0.61 μm,after 12h it is 1.2μm;after 620℃×2h diffusion annealing it is 2.1μm,after 12h it is 15.7μm;its main phase composition is TiAl3.(4)Zn can significantly reduce the inter-atomic diffusion of Ti/Al clad interface and inhibit the growth of intermetallic compounds.Compared with Ti/Pure-Al clad plate,after diffusion annealing at 550℃ for 2h,the total diffusion distance of Ti of Ti/Al-1.07Zn clad plate decreased from 1.7μm to 0.7μm and the total diffusion distance of Al of Ti/Al-1.07Zn clad plate decreased from 2.9μm to 1.9μm,The intermetallic compound layer thickness decreased from 0.61 μm to 0.34 μm.(5)Si reduces the diffusion of Al at the Ti/Al clad interface and suppresses the growth of the intermetallic compound.Compared with Ti/Pure-Al clad plate,after diffusion annealing at 550℃ for 2h,the total diffusion distance Al of Ti/Al-1.22Si clad plate decreased from 2.9μm to 2.2μm,and the intermetallic compound layer thickness decreased from 0.61 μm to 0.55μm.With the extension of diffusion holding time,the segregation of Si toward the Ti/Al-Si clad interface was segregated.With the increasing of Si content,the segregation phenomenon intensified and the bonding strength of the clad interface decreased significantly.