Brazing ZTA ceramic to TC4 alloy using the Cu foam as interlayer

In this study, a Cu foam was used as the interlayer to enhance the brazing strength of ZTA/TC4 joints. Scanning electron microscopy (SEM), energy disperse spectroscopy (EDS), X-ray diffraction (XRD) and transmission electron microscopy (TEM) were used to characterize the interfacial microstructure of the joints, which is determined to be ZTA ceramic/Ag(s,s)+Cu(s,s)/TiO + Ti3(Cu,Al)3O/Ti2Cu3/TiCu/Ti2Cu/α+β-Ti/TC4 alloy. The effects of brazing temperature and holding time on the microstructure and mechanical properties of the joints are investigated. With the increase of brazing temperature and the holding time, Ti-Cu intermetallic compound layers thickens and the brazing seam narrows. When the joints are brazed at 850 °C for 10 min, the shear strength of the joints reaches the maximum value of 84.5 MPa, displaying a 95% increase compared to the joints without the Cu foam interlayer.