Semi-solid Pressing Bonding Strength between Steel and Cu-graphite Composite

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.

Influence of Rolling Treatment on Interfacial Shear Strength of Steel-mushy Al-7graphite Bonding Plate

At room temperature, the rolling treatment of steel-mushy A1-7graphite bonding plate was carried out under different relative reduction. The influence of rolling on interracial mechanical property of this bonding plate was studied. The results show that, for steel-mushy AI-7graphite bonding plate which is made up of 1.2 mm in thickness 08AI steel plate and 2.0 mm in thickness AI-Tgraphite layer, there is a nonlinear relationship between interracial shear strength of bonding plate and relative reduction of rolling. When relative reduction of rolling is smaller than 2.59%, with the increasing of relative reduction, interracial shear strength of bonding plate increases gradually. When relative reduction of rolling is bigger than 2.5g%, with the increasing of relative reduction, interracial shear strength of bonding plate decreases continuously. When relative reduction of rolling is 2.59%, the largest interracial shear strength 77.0 MPa can be obtained.

Influence of Diffusion Time on Steel-Aluminum Solid to Liquid Bonding Interfacial Structure

The bonding of steel plate to aluminum liquid was conducted using rapid solidification.The influence of diffusion time on interfacial structure was studied.The results showed that under the condition of 750℃ for the temperature of aluminum liquid and 200℃ for the preheat temperature of steel plate,when diffusion time was shorter than 4.3s,there was only Fe-Al solid solution at the interface.When diffusion time was longer than 4.3s,Fe-Al compound began to form at the interface.The relationships between diffusion time t and thickness of Fe-Al compound layer H are H=-9.72+2.62t-0.08t^2(4.3s≤t≤15s)and H=2.79+0.647t=0.033t^2(t>15s).

Influence of Solid Fraction on Structure of QTi3.5-15/Graghite Slurry

The electromagnetic-mechanical stirring technology was used to prepare QTi3.5-15/graghite slurry. The distribution of graphite particles in QTi3.5-15/graghite slurry was studied using cold quenching method. The results show that solid fraction of QTi3.5-15/graphite slurry increases with the decreasing of stirring temperature. There is a linear relationship between solid fraction and stirring temperature. With the increasing of solid fraction, the distribution of graphite particles in slurry becomes uniform gradually. When the solid fraction is larger than 45%, the rising of graphite particles in slurry can be restricted, and QTi3.5-15/graghite slurry with uniform distribution of graphite particles can be prepared.

Interfacial Structure of Steel-Mushy Al-20Sn Bonding Plate

Fe-Al compound at the interface of steel-mushy Al-20Sn bonding plate was studied quantitatively. The relationship between ratio of Fe-Al compound at interface and bonding parameters (such as preheat temperature of steel plate,solid fraction of Al-20Sn slurry and rolling speed) was established by artificial neural networks perfectly. The results show that when the bonding parameters are 505℃ for preheat temperature of steel plate, 34.3% for solid fraction of AI-20Sn slurry and 10 mm/s for rolling speed, the reasonable ratio of Fe-Al compound corresponding to the largest interfacial shear strength of bonding plate is obtained. Its value is 72%. This reasonable ratio of Fe-Al compound is a quantitative criterion of interracial embrittlement, that is, when the ratio of Fe-Al compound at interface is larger than 72%, interracial embrittlement will occur.

Study on Mechanical Property in Steel-Aluminum Solid to Liquid Bonding

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.

Thickness of compound layer in steel-aluminum solid to liquid bonding

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.