Investigation on microstructure and internal friction for low density TiB2/ZL114 composites

TiB2/ZL114 composites with the density of 2.733 g/cm3 were fabricated through reaction of K2TiF4 and KBF4 (LSM method). The composites were characterized by X-ray diffraction (XRD) and scanning electron microscope (SEM). The internal friction measurements were performed on DTM-II-J dynamic modulus damping analyzer and the mechanisms were investigated. Experimental results indicate that reinforced particles are well-distributed in the matrix and the internal friction value of TiB2/ZL114 composites is up to a maximum of 9.04 × 10−3, almost twice that of ZL114. The internal friction results form dislocation vibration within the material, the sliding of grain boundary and phase interface, and together with the micro-plastic deformation caused by difference in coefficients of thermal expansion and elasticity modulus of various phases. The average internal friction values of samples with the sizes of 40 mm × 4 mm × 2 mm, 40 mm × 8 mm × 2 mm and 40 mm × 25 mm × 2 mm are 8.83 × 10−3, 8.89 × 10−3, and 8.93 × 10−3, respectively. Thus, the developed composites are of low density, high internal friction, and the sizes of samples have no relation to the internal friction behavior.