Diffusion bonding of a superplastic Inconel 718SPF superalloy by electroless nickel plating

Although intimate contact can be obtained for diffusion bonding of a superp lastic Inconel 718SPF superalloy under a low pressure of 7 MPa, the precipi tates formed at the interface retarded achievement of a sound joint. The sh ear strength was only 41.5 MPa for an overlap length of 12 T(T = 1.3 mm, sh eet thickness). The diffusion bondability of this Inconel 718SPF superalloy was enhanced by electroless nickel plating. In this situation, the bonding shear strength increased to 70.4 MPa for the same overlap length of 12 T u nder the same bonding condition, regardless of the roughness of the surface to be bonded. Upon decreasing the overlap length from 12 to 6 T, the bondi ng strength remained constant.