Study On Mechanical Properties And Failure Mechanism Of Vibration Cast-Rolling Ti/Al Composite Strip

Ti/Al layered composite plate is one of the popular new composite materials nowadays.Due to the large difference in the properties of Ti and Al,their composite technology has always been a research hotspot,and the layered structure also makes their mechanical properties and failure mechanisms different from single metals.In this paper,on the basis of the twin-roll casting-rolling composite process,mechanical vibration is added to prepare the Ti/Al composite strip,and it is compared with the non-vibration cast-rolling composite strip to obtain the effect of vibration on the mechanical properties and failure mechanism of the composite strip.Non-vibration and vibration casting-rolling composite tests were carried out using the twin-roll thin strip casting mill modified by our team.After many tests,the optimal vibration parameters were determined,and Ti/Al composite strips with good composite quality were obtained under the two working conditions.The microstructure characteristics of the composite strip under two working conditions were obtained through the microscopic characterization test.The two metals at the interface formed a metallurgical bond.Compared with the non-vibration composite strip,the interface of the vibration casting-rolling composite strip is straight and the thickness of the diffusion layer is reduced,and the grains on the aluminum side appear as equiaxed grains with smaller size.The mechanical properties of the composite strip are tested.The microhardness test results show that the interface hardness of the composite strip is between the two substrates.The addition of vibration makes the interface hardness value of the composite strip and the hardness value of the aluminum side higher,and less fluctuation of the hardness test curve.The tensile test results show that the vibration casting-rolling composite strip has better ductility and higher strength.In addition,the three-point bending test results show that the cast-rolling composite strip has excellent bending performance,and the addition of vibration makes it more resistant to bending.In addition,the three-point bending test results show that the cast-rolling Ti/Al composite strip has excellent bending properties,and the vibration cast-rolling composite strip has stronger bending resistance.The failure mechanism of the composite strip under different loads was studied based on the results of the mechanical test results and the microscopic characterization results.The fracture type of the cast-rolling Ti/Al clad strip under overload fracture is ductile fracture,showing the characteristics of cutting fracture,and the fracture mechanism is micro-pore aggregation type.The fracture of the specimen is accompanied by interface separation,but the nodes where the interface separation occurs are different for the specimens of the two working conditions.The failure mechanism of prefabricated notched specimens of cast-rolling clad strips under bending load is micropore aggregation type.The component metal of the vibrating composite plate is not damaged,only micro-holes appear at the interface under the action of additional stress,and the holes expand and connect to form cracks,resulting in interface debonding failure.The finite element analysis was carried out for the tensile test of the composite strip under two working conditions,the comparison results show that the simulation model established by the Ductile Damage damage failure model for the matrix and the cohesive force model for the interface layer is effective.This model can calculate the internal strain and stress field data of the composite plate that cannot be obtained by the test,and quantify the damage process.