| The bi-material structure is more and more widely applied in modern industry,such as automotive industry,refrigeration equipment,machinery manufacturing,etc.With the excellent structural characteristics and mechanical properties,this kind of composite structure not only has the advantage of the single material,but also include the strength of two kinds of materials,reflecting in its application status and using value as industrial materials.Duing to the contrast of the physicochemical property of the composition material and widely application prospect,the interface properties of bi-material always has been contain great optimization potential,it has been one important direction of academic research topic.Through to the experimental research and theoretical analysis of the aluminum/non-metal bi-material,its interface strength and failure mechanism are discussed in this paper;According to the experimental study,assess acceptance,microstructure characterization,and simulation results of the T2copper/45#steel bi-material,its interface performance of the weld zone and mechanics characteristics are discussed.(1)The interface strength of aluminum/nonmetal bi-material and the parameters of parent metal are got from the tensile experiment,then,the relationship and change rule are compared and analyzed,among the interface strength of two kinds bonding bi-material,elastic modulus,and the parameters of the material itself,under the precondition of the contrast of the weak-strong bonding sample;With the analysis of load displacement curve,the failure process of the bi-material are described;By employing the interface mechanics theory,the butt joint interface model and interface stress singularity displacement function of aluminum/nonmetal bi-material are derived,explanation and illustration of experimental special case and interface damaging are acquired,and the load displacement curve is explained base on the fracture morphology.(2)The parameter,including yield strength,tensile strength and elastic modulus,of the T2copper/45#steel is measured through tensile experiment;On the basis of the compact tensile test,the interfacial fracture of the bi-material is obtained from the three point bending test.By SEM,EDS and XRD experiment,the microscopic characteristics and chemical composition of weld zone are characterized,and the defect distribution location of porosity and micro cracks are determined in the weld zone;The fractography and fracture type of tensile test and three point bending test are decided by SEM experiment.Combination the interface failure characteristics and crack propagation direction of tensile test and three point bending test,the crack propagation and defection of the T2copper/45#steel are summed up under the condition of quasi-static loading.(3)The defect evaluation results of T2copper/45#steel bi-material are accepted,according to the impact energy from the Charpy pendulum impact test and BS7910 defect evaluation standards.Through the SEM experiment to determine the micro characteristics of bi-material and fracture type,it is concluded the crack deflection of T2copper/45#steel bi-material under impact load.(4)The XFEM method is used to simulate crack propagation of T2copper/45#steel bi-material with experimental conditions and boundary conditions;The SEAM method is utilized simulate to calculate the fracture toughness of T2copper/45#steel bi-material.The results of contrast experiment results and simulation show the interface crack path and deflection of bi-material.In summary,the research results of interface fracture morphology,mechanical properties and failure form plays an important role for improving the structural stability and bearing capacity.The bi-material interface failure mechanism and failure form reached by relevant experimental study and theoretical analysis,lays the foundation for further research,having the certain guiding role. |
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