Damping capacity of BaTiO3/Al composites fabricated by hot extrusion
(State Key Laboratory of Metal Matrix Composites, Shanghai Jiao Tong University, Shanghai 200240, China)
Abstract: To develop new type of high damping metal matrix composites, large grain size barium titanate (BaTiO3) ceramic was sintered and added into Al powder to fabricate BaTiO3/Al composites through the powder metallurgy method and hot extrusion. The damping properties of BaTiO3 ceramic, Al matrix and BaTiO3/Al composites were examined by dynamic mechanical analysis in the temperature range from 273 K to 573 K. The results show that although BaTiO3 exhibits high damping (tan δ=0.12) below 400 K, the damping capacity of 10%BaTiO3/Al (mass fraction) composites below 400 K is not increased as compared to the Al matrix. On the other hand, the damping capacity above 450 K is greatly enhanced due to the motion of dislocations at the interfaces between ceramic particles and Al matrix. The failure of exerting the intrinsic damping of BaTiO3 particles in the composites is attributed to the poor interface bonding between the particles and the matrix. The tensile strength of the composite is 42% higher than that of the Al matrix, which indicates the possibility of obtaining high strength and high damping composites via interface improvement and the addition of high volume fraction of large grain BaTiO3 particles.
Key words: high damping materials; metal matrix composites; barium titanate; mechanical properties; interface