Fracture Characteristics Of Electron Beam Welding Of T2 Copper-45 Steel Bi-material

The bi-material composite structure has been widely used in aerospace,heat exchange equipment and other industries.This is because the bi-material structure not only has the advantages of a single material,but also has special mechanical properties.If the characteristics of the two different materials are combined,it means that it has a large application space in the actual industry.Bi-materials usually contain two different materials,their physical properties and chemical compositions are very different from their application prospects.Therefore,there is still a lot of space for the study of bimaterials.At the same time,a large number of studies have shown that the subject has always been the focus of scholars.Based on the specimen preparation,experimental discussion and numerical simulation of electron beam welding copper/steel bi-materials,the mechanical properties and fracture characteristics of copper/steel materials were discussed.The main contents and results of this paper are as follows:(1)Combining orthogonal experiment method to set the welding test parameter set,discuss the influence of electron beam welding process parameters on the mechanical properties of copper/steel double materials,and obtain better process parameter sets and welded joints with better tensile properties.(2)The ultimate tensile test and three-point bending test were carried out.The crack propagation direction of copper/steel bi-materials was analyzed.The fracture modes of copper/steel bi-materials were analyzed by comprehensive macroscopic and micro fracture morphology and the fracture toughness of copper/steel bi-materials was determined according to the standard.(3)Small punch tests were carried out on copper/steel bi-materials using three small punching positions,and the main reasons for the small punch test of copper/steel bi-materials were analyzed.The applicability of the fracture toughness of copper/steel bi-material based on small punching test data is discussed.The fracture toughness value of copper/steel bi-material is obtained,which is better than the traditional three-point bending test.The potential for determining fracture toughness using a small punch test was verified.(4)Based on the theory of welding heat transfer and damage fracture,a numerical simulation model of small punch test is constructed by using finite element analysis software ABAQUS.The distribution of stress and strain fields is analyzed and some exploratory research work is carried out.