| This paper study on T2 copper and 304L stainless steel vacuum diffusion welding,and its microstructure and mechanical properties,the following conclusions can be drawn:(1)Vacuum diffusion welding of T2 copper to 304L stainless steel was realized under the conditions of vacuum degree of 0.4 Pa,pressure of 20～25 MPa,temperature of 800～950℃ and welding time of 30 minutes.(2)The tensile test results show that the fracture occurred on the copper base metal side,away from the welded joint.The tensile strength of the specimen is 188.81MPa,the average elongation is 39.3%,and the area shrinkage is 64.32%.The impact test results show that the impact energy at the interface is 102.67 J,not less than the impact energy of the T2 copper base metal.The results of 180° bending test show that there is no crack in the joint interface.The results of torsion experiments show that the fracture is far away from the interface and located on the side of the copper matrix.The results of high frequency fatigue test showed that the fracture occurred on the side of the copper base material and away from the interface.At 2 ×106 cycles,the fatigue strength of the fatigue specimens is 55.11MPa and 54.76MPa under the conditions of 50%and 95%survival rate,respectively.(3)The analysis of OM,SEM,EDS,XRD,etc.showed that the interface near the interface area diffusion,the interface appeared a width of 50-60μm Diffusion region.Chromium is diffused from 304L stainless steel to T2 copper,and the interfacial interface is mainly composed of Cu and Cr-Ni-Fe-C phase.(4)The microhardness test results show that the hardness value of the interface is higher than that of T2 copper,which is due to the solid solution strengthening of Cr element.(5)Fatigue crack can be observed in the crack source,the expansion area and the instantaneous fracture area.The fatigue crack originates from the surface of the specimen.Fatigue crack growth zone,step and tear edge exist in the fatigue crack growth area.And micro-craters,and the fracture surface of the fracture zone has a ductile fracture.substrates 304 stainless steel. |
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