Study On The Bonding Interface And Mechanical Properties Of Steel Fiber Reinforced Steel/aluminum Composite Plate

Steel/aluminum composites prepared by explosive welding are widely used in protective engineering due to their excellent corrosion resistance of aluminum and high strength of steel.In addition,during explosive welding,the strengthening effect of metal materials promotes their strength to a certain extent,with austenitic steel being most significantly strengthened by explosion.Steel fiber has the advantages of small mass,high strength,fatigue resistance,high elastic modulus,etc.It also has great potential in improving the mechanical properties of metal matrix composite.Therefore,in this paper,steel fiber reinforced steel/aluminum composite plates were prepared by explosive welding,and the element transition,wavy interface,and mechanical properties of the bonding interface region between steel fiber and composite plates were deeply studied.The specific research is as follows:(1)The process of successfully fabricating steel fiber reinforced steel/aluminum composite plates by explosive welding is described in detail.The effect of steel fiber addition on the vortex region generated at the interface of the steel/aluminum composite plate is studied using the smooth particle hydrodynamics(SPH)method,and the process of defect generation in the vortex region is successfully reproduced.The addition of steel fiber prevents the continuous action of j et particles on the surface of the substrate and clad plate,It forms a certain angle with the substrate and clad plate,causing a large number of high-temperature jet particles to accumulate on the single side of the steel fiber,resulting in a high-temperature,high-pressure,and high strain rate environment on the single side of the steel fiber,leading to vortex regions and defects.(2)By using scanning electron microscopy(SEM)and energy dispersive spectroscopy(EDS)to analyze the vortex region,the following conclusion was drawn:under high temperature,high pressure,and high strain rate environments,brittle iron and aluminum intermetallic compounds were generated in the vortex region,leading to the appearance of cracks,pores,and pores.The experimental results were highly similar to the simulated vortex region.(3)The element transition at the bonding interface of composite plates was studied.The results showed that the element transition region at the bonding interface of steel/aluminum composite plates was 4 um.The element transition region at the bonding interface of steel fiber reinforced steel/aluminum composite plate is only 2 um.Compared to adding steel fiber,the element transition in the group without adding steel fiber is more obvious,and the mixing amount of the two elements in the transition zone is larger.(4)Although the addition of steel fibers leads to defects at the bonding interface,tensile experiments show that in the direction of steel fibers parallel to the tensile load,when the diameter of steel fibers is 0.25 mm,the tensile resistance increases the lowest,increasing by 7%.When the diameter of steel fibers is 0.5 mm,the tensile elongation increases the highest,increasing by 38.6%;In the direction of steel fiber perpendicular to the tensile load,when the diameter of steel fiber is 0.25 mm,the tensile resistance increases the lowest,increasing by 2.2%.When the diameter of steel fiber is 0.5 mm,the tensile resistance increases the highest,increasing by 11.2%.In summary,the addition of steel fibers can improve the tensile resistance of steel/aluminum composite panels to a certain extent,and the larger the fiber diameter,the more obvious the improvement in tensile resistance.(5)The microhardness of the sample with a diameter of 0.5 mm of steel fiber was tested and the fracture surface of the sample after tensile fracture was scanned by SEM.The following conclusions were drawn:Due to the presence of intermetallic compounds and the main composition of the vortex region being 2A12 aluminum,the microhardness of the vortex region decreased.However,due to the obvious explosive strengthening effect on SS-304 stainless steel,the microhardness of the steel substrate layer has increased to 419 Hv.Therefore,obvious tear edges and holes can be observed in the steel substrate layer,so the steel layer undergoes quasi cleavage fracture.However,explosive strengthening has almost no effect on the hardness of 2A12 aluminum.From the fracture morphology of 2A12 aluminum layer,it can be observed that the fracture surface is porous and has an obvious dimple morphology,so the fracture of 2A12 aluminum layer belongs to ductile fracture.