Study on Inhibition of Interfacial Compounds and Improvement of Joint Properties by Low Temperature and High-Pressure Process in Diffusion Bonding of Ti/Cu

The vacuum diffusion bonding of Ti/Cu under low temperature and high pressure was prepared to explore a suitable process to inhibit the formation of Ti-Cu intermetallic compounds and thus effectively improve the strength of Ti/Cu joints. The conventional diffusion bonding of Ti/Cu joint was also compared and analyzed. The diffusion process, especially the bonding temperature, significantly influences the morphology of the joint interface. At a lower diffusion temperature (550-580 degrees C) and a larger bonding pressure (30 similar to 40 MPa), the effective bonding of Ti/Cu was realized. Low temperature inhibited the nucleation and growth of intermetallic compounds, and the types and thicknesses of intermetallic compounds at the interface decreased significantly. The interface of the Ti/Cu joint prepared at 55 degrees C- 40 MPa formed an amorphous transition layer with a width of approximately 10 nm, rather than a brittle intermetallic compound layer. The grain size of the transition layer was mainly concentrated in the range of 0.25-1.05 mu m. The hardness distribution of the sample did not show an obvious increase. The shear strength of the Ti/Cu joint at 580 degrees C-30MPa reached 181 MPa.