| Explosive welding is a widely used techniques in the manufacture of composite plate.It is well known that explosive welding can directly weld similar metals and dissimilar metals that are not easy to be welded by other technique.Since its introduction into the industry by Phillpchuk,explosive welding has become a widely used technique in the manufacture of composite plates such as ship materials,chemicals,pharmaceuticals,transportation,and aerospace.Today,the explosive welding has developed a relatively complete theoretical system,but the influence of microstructure on its mechanical properties and practical applications is still unclear.This paper produced two kinds of composite plates(5083 aluminum alloy-1060 pure aluminum-CCSB steel,3A21 aluminum alloy-TA1 pure titanium-NiCr low alloy steel),and their bonding interfaces(aluminum-aluminum,Aluminum-steel,aluminum-titanium,and titanium-steel)were observed and analyzed to study the effect of the microstructure of the bonding interface on mechanical properties and practical applications.The microstructure and composition of the bonding interface were analyzed by metallographical microscopic and scanning microscopy with EDS.It is found that composite plates were successfully welded by the explosive welding process.Metallurgical bonding of the explosive welding interface was achieved at bonding interfaces,no macro-cracks appeared.The bonding interface demonstrated a wavy structure and some vortices were formed at the crest of the wave.Different kinds of intermetallic compounds were formed after explosive welding:These intermetallic compounds appeared in the vortex regions enclosed by the matrix or appeared at the bonding interface area.The paper also studied the relationship between microstructure and mechanical properties by hardness analysis,tensile,shear and bending tests.The interface of explosively welded composite plates exhibited reliable shear strength,tensile strength,and bending properties.The cracks could easily generate in the intermetallic compound regions at the vortex region,but the crack propagation was hindered by the refined matrix.The inhomogeneity of the bonding interface ensured that the cracks could not propagate along the bonding interface and enhanced the mechanical properties of the explosively welded composite plates.The mechanical properties and corrosion performance of the composite plate was identified by bending fatigue strength test and salt spray weight loss test.As a result,the interface of the composite plate is stronger under the fatigue load,and no delamination occurs.The 1gN-1gS relationship of the two composite plates was obtained through the fatigue performance test of the composite plate.The curve obtained by the aluminum-aluminum-steel was 1gS=-0.19151·1gN+3.48208,and the curve obtained by the aluminum-titanium-steel was 1gS=-0.20234·1gN+3.48253.The two plates have sufficient fatigue life to meet the requirements of the actual working conditions..The source of the bending fatigue crack is mostly generated on the surface of the substrate of the tension surface and the vertical surface is inwardly expanded,and the crack is not initiated in the weld;Salt spray weight loss experiment suggests that the steel substrates of both composite panels were fully corroded.There is a strong tendency for galvanic corrosion on the composite interface,and also visible crevice corrosion. |
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