Search

Tungsten fiber reinforced tungsten (W f /W) composite is one of the candidates to improve the toughness of tungsten materials. Powder metallurgy is a potential method to produce W f /W composites, but it may cause the recrystallization and grain growth of the reinforcing fibers during the high temperature sintering process. In the present work, a layer of Y 2 O 3 is coated on the fiber surface by magnetron sputtering to protect the fibers and prevent recrystallization and abnormal growth of grains. W f /W composites with and without Y 2 O 3 coating were fabricated by a field assisted sintering technology (FAST) process. Microstructure and mechanical properties were characterized. The influence of the Y 2 O 3 coating on the properties of the fiber was discussed in detail. The Y 2 O 3 coating can effectively prevent recrystallization and abnormal grain growth of fibers during the sintering process. The W f /W composites with Y 2 O 3 coating shows higher strength and pseudo-ductile behavior. • Continuous fiber reinforced W f /W composites are fabricated via PM. • Y 2 O 3 coating can prevent recrystallization and abnormal grain growth of fibers during the sintering process. • The improvement of the toughness is mainly contributed by the high strength of the fiber. [ABSTRACT FROM AUTHOR]

Abstract 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. Highlights • W/Ti multilayer composites are prepared by spark plasma sintering. • The detailed microstructure of W/Ti laminates can be divided into four layers. • The formation mechanism of the microstructure is determined. • The strengthening mechanism in the Ti layer is proposed. [ABSTRACT FROM AUTHOR]