Effect of the annealing process on the microstructure and mechanical properties of multilayered Zr/Ti composites

To explore the potential application of Zr-based alloys as structural materials, multilayered Zr/Ti composites were fabricated by a vacuum diffusion annealing bonding process. Scanning electron microscopy (SEM) in tandem with energy dispersive spectroscopy (EDS) and electron backscatter diffraction (EBSD) was used to characterize the microstructures and chemical elemental distributions of the Zr/Ti laminated metal composites (LMCs). Micro-hardness and in-plane compression tests were conducted to evaluate the mechanical properties of the Zr/Ti LMCs. It is revealed that the microstructure of the Zr/Ti LMCs is composed of alternating Zr layers, Ti layers and Zr-Ti mutual diffusion layers (interface layers). The width of the interface layer increases with increased annealing temperature and time. The micro-hardness test results show that the hardness distribution is uneven among the different layers and that the interface layer has the highest hardness. Compression results indicate that the strength of the Zr/Ti LMCs are higher than that of the constituent materials due to the contribution of the interface layer. The diffusion coefficient and the relation between the microstructure and yield strength are also discussed in this study.