| Because of metal composite plates have excellent comprehensive properties, the production costcan be greatly decreased when they are used in practical engineering structure, so they are widelyused in many industry fields such as aerospace, petrochemical, communication transport andarchitecture, etc. At present, explosive welding technology is one of the ways often used infabricating metal composite plates. In this paper, the TA2-2A12composite plate is made by usingexplosive welding, which has great potential in aviation and chemistry industry. Through the testsof mechanical properties and the analysis of microstructure for TA2-2A12composite plate, theexplosive welding parameters are optimized under the experimental condition, it is expected thatthe technical guidance can be provided when the composite plate is applied in practicalproduction.The results of mechanical properties tests show that the tensile strength of TA2-2A12composite plate is424.7MPa, which is a little higher than that of theoretical calculation value,417.7MPa. The shear strength of composite plate is72.1MPa. The bending property of compositeplate is better, and no crack occurred in the interface till the bending angle reachs180°duringbending test. The test of microhardness distribution demonstrates that the hardness value ofinterface is maxium, and the hardness values in both sides of base metals gradually decrease withthe increase of distance from the interface. The work-hardening zone in the side of TA2is widerthan that side of2A12.Metallographic structure observation indicates that the interface of composite plate is bondedwith the pattern of wave, and the adiabatic shear bands (ASB) are generated in local region ofTA2side, which results in adiabatic shear deformation of TA2side during explosive welding. Theform of ASB probably causes to crack. The analysis of alloy element line scanning shows that theelement Ti and Al diffuse each other short distance in the interface, and the diffusion area is about2.1μm. The diffusion between element Ti and Al is advantageous to improving the bondingstrength of composite plate. Results of XRD phase constituent and EDS analysis indicate that nointermetallic compound produces in interface. Tensile fracture scanning observation shows thatthere are many dimples distributed on the fracture surface of composite plate, which it obviouslypresents the characteristics of ductile fracture.TEM observation of substructure verifies that therapidly-melting occurred in the side of TA2nearby interface during explosive welding. There are dislocations with high density in the work-hardening area, and the substructure of twin crystalformed in local work-hardening area.In order to eliminate the residual stress exsited in bonding region of composite plate, and toimprove the microstructure and properties of composite plate, annealing treatment is carried out toTA2-2A12composite plate. The tests of mechanical properties and analyses of microstructure ofcomposite plates are conducted after annealing treatment, including bonding interface observation,tests of microhardness and shear strength, the measurement of intermetallic compounds in theinterface, etc. The heat treatment of440℃×3h is chosen for the TA2-2A12composite plate inthis paper.Static weight loss experiment and electrochemical corrosion test are used respectively toevaluate the corrosion resistance of TA2-2A12composite plate, and which is compared to that ofbase metals. The result of static weight loss experiment shows that the corrosion pits of TA2basemetal are few and shallow, while the2A12base metal are much and deep. The corrosion ofcomposite plate mainly concentrates in interface and the side of2A12. The rank of mass losscorrosion rate is:2A12> TA2-2A12> TA2. According to the dynamic potential polarizationcurves, the result of electrochemical corrosion test indicates that the rank of self-corrosionpotential of three samples is TA2> TA2-2A12>2A12, Namely, the capability of corrosionresistance of three samples is TA2> TA2-2A12>2A12. It is corresponding to the test result ofelectrochemical impedance spectroscopy (EIS). On the whole, the TA2-2A12composite plate hasbetter corrosion resistance under the experimental condition. |
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