Effect of bonding temperature on microstructure and mechanical properties of dissimilar joint between Ti–6Al–4V and Co–Cr–Mo biomaterials

Abstract

Transient liquid phase (TLP) technique has excellent potential for producing bimetallic devices in medical applications. TLP bonding between Co–Cr–Mo and Ti–6Al–4V metallic biomaterials was carried out using copper interlayer with a thickness of 10 μm at the bonding temperature of 900, 920, 940, and 960 °C. The effect of bonding temperature on the microstructural and mechanical characteristics was investigated. The results showed that the increase in the bonding temperature leads to the enlargement of the interfacial brazing zone (IBZ). Also, the reactive layer width is enlarged due to the increase in the eutectic liquid volume. Several intermetallic compounds such as Ti(Co, Cu), Ti2(Co, Cu), and CoCr(Ti, Mo) are identified in the IBZ. The bonded joint at 920 °C has the maximum strength equal to 277 MPa. The cleavage pattern dominates on the fracture surfaces owing to the formation of brittle phases in the dissimilar joints. The diffusion layer of the Co–Cr–Mo base metal has the highest hardness in the IBZ.