Transient liquid phase diffusion bonding of a single crystal superalloy DD6

DD6 alloy was bonded by transient liquid phase(TLP) diffusion bonding.The main compositions of the interlayer alloy were similar to those of the DD6,base metal,and a certain amount of element B was added as the melting point depressant.The results show that it is difficult to obtain the joints with the microstructures completely homogeneous.For the joint TLP diffusion bonded at 1 290 ℃ for 12 h,about half areas of the beam possessed a γ+γ' microstructure,nearly identical with that of the base metal,and the other local areas consisted of γ-solution,borides,etc.Prolonging the bonding time to 24 h,the inhomogeneous areas in the joint reduced,and the joint property improved.The joint stress-rupture strength at 980 ℃ and 1 100 ℃ reached 90%-100% and 70%-80% of those of the base metal respectively.