Effect Of V-Ni And V-Ti Alloy Powder Interlayer On Diffusion Bonding Of W/MA956 Steel

In this paper,tungsten and MA956 steel were joined by diffusion bonding,V-Ni and V-Ti composite powder interlayer were used respectively to explore the influence of different interlayer and process parameters on diffusion bonding.The V-Ni composite powder was evenly mixed with 40wt%Ni content.Under different interlayer thickness of 50?m,100?m,150?m by vacuum diffusion bonding,the optimal interlayer thickness was 100?m and the shear strength was 150MPa.Under the optimal interlayer thickness,the shear strength of the joint reached 286mpa at60wt.%with the increase of Ni content.When the Ni content is 40wt.%by spark plasma sintering technology,the best holding time of diffusion bonding is 20min and the shear strength is 225MPa in different holding time of 10min,20min and 30min.The middle layer of V-Ti composite powder was fully mixed with the powder in the ratio of 1:1,and the optimal diffusion temperature was determined in the welding temperature range of 800?,850?and 900?,respectively.Under the optimal diffusion temperature,the optimal holding time was explored by holding for 5 min,20min and 35 min,respectively.When the diffusion temperature is 850?and the holding time is 20 min,the quality of the welded joint is the highest,and the shear strength of the joint reaches 289 MPa.In addition to a large amount of W,a small amount of V and Ti were also detected on the fracture surface.For V-Ti-Y₂O₃composite powder interlayer with Y₂O₃addition,under the optimal diffusion temperature of 850?and holding time of 20min,0.5wt.%,1wt.%,2wt.%Y₂O₃powder was added to the intermediate layer of V-Ti composite powder and mixed fully.When Y₂O₃content is0.5wt.%,the quality of welded joint is the highest,and the shear strength of welded joint reaches 296MPa.In the test,the highest hardness is in the middle layer area,and there is about 100?m softening zone near the middle layer.In the shear test,the fracture position of the joint is the side of the interlayer close to the tungsten,which indicates that the most vulnerable part of the mechanical properties test of the diffusion joint is the side of the interlayer close to the tungsten matrix.