The bonding of a steel plate to A1-20Sn slurry was conducted using the casting rolling technique. The surface of the steel plate was defatted, descaled, immersed (in K2ZrF6 flux aqueous solution) and stoved. A1-20Sn slurry was prepared using the electromagnetic mechanical stirring method. The interfacial mechanical property of the bonding plate was researched to determine the relationship between the diffusion time and the interfacial shear strength. In order to identify the mechanism of bonding, the interfacial structure of the bonding plate was studied. The results show that at a preheat temperature of the steel plate of 505℃ and a solid fraction of A1-20Sn slurry of 35%, the relationship between the interfacial shear strength S and the diffusion time t is S=28.8+4.3t-0.134t2 +0.0011t3. When the diffusion time is 22 s, the largest interfacial shear strength is 70.3 MPa, and the corresponding interface is a new one which is made up of Fe-A1 compound and Fe-Al solid solution alternatively and in a right proportion.In this interfacial structure, the interfacial embrittlement does not happen and Fe-Al compound can play its role in strong combination adequately.
The bonding of solid steel plate to liquid al uminum was studied using rapid solidification. The relationship models of interf acial shear strength and thickness of interfacial layer of bonding plate vs bond ing parameters (such as preheat temperature of steel plate, temperature of alumi num liquid and bonding time) were respectively established by artificial neural networks perfectly.The bonding parameters for the largest interfacial shear stre ngth were optimized with genetic algorithm successfully. They are 226℃ for preh eating temperature of steel plate, 723℃ for temperature of aluminum liquid and 15.8s for bonding time, and the largest interfacial shear strength of bonding pl ate is 71.6 MPa . Under these conditions, the corresponding reasonable thickne ss of interfacial layer (10.8μm) is gotten using the relationship model establi shed by artificial neural networks.
The bonding of solid steel plate to liquid Al was conducted using rapid solidification. The influence of thickness of FeAl compound layer at the interface on interfacial shear strength of bonding plate was studied. The results show that the relationship between thickness of Fe-Al compound layer and interfacial shear strength is S=30.4+8.51 h-0.51 h2+0.007 ha (where h is thickness of Fe-Al compound layer, S is interfacial shear strength). When thickness of Fe-Al compound layer is 10.7μm, the largest interfacial shear strength is 71.6 Mpa.
The bonding of solid steel plate to liquid aluminum was studied using rapid solidification. The surface of solid steel plate was defatted, descaled, immersed (in K2ZrF6 flux aqueous solution) and stoved. In order to determine the thickness of Fe-A1 compound layer at the interface of steel-aluminum solid to liquid bonding under rapid solidification, the interface of bonding plate was investigated by SEM (Scanning Electron Microscope) experiment. The relationship between bonding parameters (such as preheat temperature of steel plate, temperature of aluminum liquid and bonding time) and thickness of Fe-Al compound layer at the interface was established by artificial neural networks (ANN) perfectly. The maximum of relative error between the output and the desired output of the ANN is only 5.4%. From the bonding parameters for the largest interfacial shear strength of bonding plate (226℃ for preheat temperature of steel plate, 723 ℃ for temperature of aluminum liquid and 15.8 s for bonding time), the reasonable thickness of Fe-A1 compound layer 10.8 μm was got.
The pressing bonding of steel plate to QTi3.5-3.5 graphite slurry was conducted. Under the conditions of 530 ℃ for the preheat temperature of dies, 45% for the solid fraction of QTi3.5-3.5 graphite slurry, 50 MPa for the pressure and 2 min for the pressing time, the relationship between the preheat temperature of steel plate and interfacial mechanical property of bonding plate was studied. The results show that when the preheat temperature of steel plate is lower than 618 ℃, the interfacial shear strength of bonding plate increases with the increasing of the preheat temperature of steel plate. When the preheat temperature of steel plate is higher than 618 ℃, the interfacial shear strength decreases with the increasing of the preheat temperature of steel plate. When the preheat temperature of steel plate is 618 ℃, the highest interfacial shear strength of bonding plate of 127.8 MPa can be got.
The pressing bonding of steel plate with QTi3.5-3.5graphite slurry was studied. The relationship among preheating temperature of steel plate, preheating temperature of dies, solid fraction of QTi3.5-3.5graphite slurry, and interfacial shear strength of bonding plate could be established with artificial neural networks perfectly. This model could be optimized with a genetic algorithm. The results show that the optimum bonding parameters are: 618℃ for preheating temperature of steel plate, 526℃ for preheating temperature of dies and 46.2% for solid fraction of QTi3.5-3.5graphite slurry, and the largest interfacial shear strength of bonding plate is 128.3 MPa.