The microstructure and property of W/Ti multilayer composites prepared by spark plasma sintering

The W/Ti multilayer composites are prepared by spark plasma sintering. The original constituents are cold-rolled W foils with elongated grains and annealed Ti-1.5Al foils with fine equiaxed grains. After diffusion bonding, both elongated grains and fine equiaxed grains can be seen in the W layers. The diffusion rate of W in Ti is much faster than that of Ti in W due to different methods of diffusion. The detailed microstructure of W/Ti laminates can be divided into four types at different regions including pure W, mixture of α-W and β-Ti with light and dark lamellas, pure β-Ti and Ti-rich Widmanstäten α-β structure with alternative light and dark lamellas. Compared with the microhardness of original materials, the microhardness of W layers slightly decreases and the microhardness of Ti layers increases dramatically.