Microstructure evolution, elemental diffusion behavior, and bonding strength of TA1/AZ31B laminated composite fabricated by hot pressing

Ti/Mg composites can combine the benefits of Ti and Mg in terms of mechanical properties, cost, and other factors, making them highly valuable for various applications. In this study, Ti/Mg laminate composites were prepared by vacuum hot pressing at temperatures of 350 °C, 400 °C, and 450 °C for 6 h, 8 h, and 10 h, respectively. The study aimed to examine the effect of the diffusion behavior of elements and microstructure on the bonding strength of Ti/Mg laminate composites. The shear strength test results indicated that the laminated composites displayed a strong bonding strength at 400 °C, while a significant decrease in bonding strength was noted at 350 °C and 450 °C. Results of TEM analysis show that when the temperature is 350 °C, the intermetallic compound is not observed at the interface; when the temperature increased to 400 °C, a transition region along the interface is observed, and there is a Ti 3 Al compound in the region, the compound is uniformly distributed along the interface; when the preparation temperature is 450 °C, intermetallic compounds were observed at the interface, and the compounds were TiAl, TiAl was not uniformly distributed along the interface. EBSD analysis showed that in the Mg matrix of the composites, the distribution of coarse crystals and fine crystals was obvious due to the dynamic recrystallization, and such a distribution of grain size was also conducive to the further enhancement of the bonding strength of the composites. It can be concluded that the formation of intermetallic compounds with a continuous distribution of the transition region caused by elemental diffusion and the enhancement of the mechanical properties at the matrix are both effective in improving the bond strength of composites.