Effect of Heat Treatment on the Mechanical Properties and Interface Structure of 3-ply Ti/Cu/Ti Clad Composite

The effect of heat treatment on the mechanical properties and interface structure of 3-ply Ti/Cu/Ti clad composite was investigated. Strength decreased and the ductility increased with increase of heat treatment temperature. The gradual increase of hardness at 700°C and 800°C indicates the growth of intermetallic compounds at the interface. No visible intermetallic compound formation was observed up to 400°C. The intermetallic layer grew very rapidly above 600°C and its thickness reached ~10μm after heat treatment at 800°C. The absence of cracks emanating from the corners of the indentation mark indicates that intermetallics in Ti/Cu/Ti clad are ductile enough to accommodate the micro-plastic flow from indentation. Four intermetallic layers at the interface were confirmed to be Cu4Ti, Cu3Ti2, CuTi and CuTi2 based on the EDS spectra, XRD and phase diagram analyses.