Joining of yttria stabilised zirconia to Ti6Al4V alloy using novel CuO nanostructure reinforced Cu foam interlayer.

• YSZ and Ti6Al4V were successfully brazed using an N-Cu foam as the interlayer. • The shear strength of joints was improved by 83.1% when N-Cu foam was introduced. • The 3D structure and secondary phases could relieve the residual stress in the joint. This paper introduces a novel method to moderate the residual stress in a YSZ/Ti6Al4V alloy by using novel CuO nanostructure reinforced Cu foam (N-Cu foam) interlayer. The microstructure of the CuO nanostructure reinforced Cu foam interlayer and the achieved brazing joint is characterised via scanning electron microscope (SEM), X-ray diffraction (XRD) and transmission electron microscopy (TEM). It is found that nano-CuO structures can be successfully fabricated on the skeleton of the Cu foam and the 3D porous structure of which survives after the brazing process. The achieved brazing seam mainly consists of Ag solid solution (Ag(s,s)), Cu solid solution (Cu(s,s)) and fine Ti 3 Cu 3 O secondary phases, which is found to be beneficial to release the thermal stress. The strength of the joint achieved with an N-Cu foam interlayer is 95.6 MPa, which is 83.1% higher than the joints brazed without interlayers. [ABSTRACT FROM AUTHOR]