| The metal composite plate makes full use of the physical, chemical and mechanical properties ofdissmilar materials, and simultaneously it can greatly decrease the consumption of precious metals，consequently, the metal composite plates are extensively used in many fields such as petroleumchemical industry, shipbuilding, military industry and atomic energy, etc, due to its combination ofboth performance and cost. The same or different kinds of metal plates can be firmly bonded eachother instantaneously by the using of explosive welding, which is an important manufacturetechnology for meatl composite plates, and it is widely used in the industry production. There aremany factors which affect the quality of explosive composite plates. If the technology is not wellcontrolled during explosive welding, the weld defects such as lack of fusion, inclusion andmicro-crack, etc, are generated in the bonding interface of composite plate, as a result, it will greatlydecrease the performance of composite plate. Based on these, in this paper, the TA2-Q345compositeplate and B30-Q345composite plate which are widely used in industry fields are producedrespectively with explosive welding. The mechanical properties and microstructure of compositeplates are systematically analyzed, and the explosive technology parameters are optimized under theexperimental condition. It is expected to provide theoretical guidance and technical support for thepractical application of dissimilar metal composite plate.The results of mechanical properties tests show that the tensile strength of the two kinds ofcomposite plates reaches550MPa and483.3MPa respectively, which is higher than that of compositeplate with theoretical calculation. The shear strength of composite plates reaches222.3MPa and220.1MPa respectively. The results of180°bend test show that there is no crack on the surface ofcomposite plates, and the separation does not generate at the interface between cladding plate andbase plate after bending. The test results of microhardness distribution show that the highestmicrohardness appears in the interface of composite plate, and the microhardness becomes lower asthe distance is farther away from the interface. The main reason for the increase of microhardness isthe work hardening effect caused by plastic deformation.The microstructure observation, chemical composite analysis, phase structure constitution testand submicrostructure analysis of bonding interface of the two kinds composite plates are conductedby means of optical microscopy(OM), X-ray diffractometer(XRD), scanning electronmicroscope(SEM), togethering with transmission electron microscope(TEM) respectively. Results show that the bonding interface of the two kinds of composite plates presents the pattern ofperiodically wavy connection. The bonding interface of Titanium-Steel composite plate belongs to thethe pattern of big wave combination, and with the characteristics of wave front swirl, while theCopper-Steel composite plate presents the pattern of small wave combination. Great plasticdeformation occurs in both sides metals of bonding interface, and the adiabatic shear bands (ASB) aregenerated in the TA2base metal, which is caused by intense plastic deformation under the conditionof high strain rate. At the same time, the ASB is also a kind of crack source. The element linescanning analysis indicates that the main alloy elements obviously present the characteristic ofgradient distribution in bonding interface, and the diffusion phenomenon occurs among alloy elements.However, there is no hard intermetallic compound precipitation in the bonding interface according tothe results of XRD and TEM analyses.The electrochemical corrosion resistance of two kinds of composite plates is evaluated inartificial sea water with the measurements of dynamic potential polarization curve andelectrochemical impedance spectroscopy(EIS) respectively, and the results are compared to theelectrochemical corrosion resistance of TA2pure titanium and B30cupronickel respectively. Resultsshow that boths of the cladding metal and composite plate present passivity, the corrosion rates of allmaterials are low and no obvious pitting corrosion occurs. But in comparison, the corrosion current ofcladding metal is lower, and the corrosion resistance of cladding metal is excellent, while thecorrosion resistance of composite plate decreases slightly. The tests of electrochemical impedancespectroscopy(EIS) show that the passivation films on the surface of TA2pure titanium and B30cupronickel are more stability, the results is consistent with dynamic potential polarization curve.Compared to the corrosion resistance of cladding metals, the corrosion resistance of the two kinds ofcomposite plates slightly decreases under the experimental condition, but the decrease extent is little,which can satisfy the requirement of corrosion resistance to practical engineering structure. |
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