Microstructure and mechanical properties of transient liquid phase bonded TiCP/AZ91D joints using copper interlayer

Compositional changes, microstructural evolution and mechanical properties of transient liquid phase bonded TiCP/AZ91D joints depend on both bonding time and bonding temperature. With an increase in times from 1 min to 60 min at 510 °C, Cu content in the joint centerline decreased and the joint microstructure changed from Cu solid solution, Cu2Mg, Mg solid solution and CuMg2 to Mg solid solution, CuMg2 and TiC. Increasing the temperature to 530 °C resulted in a joint microstructure consisting of Mg solid solution, CuMg2 and TiC. Also, TiC particulates were found to aggregate along the joint centerline when the time was 20 min and 60 min. The increased amount of CuMg2 and aggregation of TiC particulates were the main reason for decreasing the joint shear strength. At 530 °C for 20 min, the joint shear strength reached 69.19 MPa which is 77.74% of original TiCP/AZ91D material strength.