Search

In this study, using a solution casting process, thermoplastic polyurethane elastomer (TPU) composites containing different contents of lead zirconate titanate (PZT) ferroelectric particles were produced. The damping treatment of composites at high volume of fillers was investigated. SEM micrographs showed that PZT particles had a proper distribution in the PU matrix. Differential scanning calorimetry (DSC) thermograms indicates that melting enthalpy decreases by raising PZT filler content. The results of the dynamic mechanical thermal analysis (DMTA) proved that the magnitude of loss factor (tan δ) strongly depends on PZT content, and it decreased from 0.51 to 0.27 as PZT content increased. The value of E 0 increases to 0.32 GPa in the composite reinforced with 50 v% of PZT. The role of PZT on the acoustic behavior of TPU was measured using the acoustic absorption coefficient (a). The results showed that as PZT content increased from 0 to 50%, the acoustic absorption coefficient reached 0.25 at 6000 Hz frequency. The composites of PZT/PU with 0–3 connectivity were poled, and the optimal poling conditions that could be applied without sample breakdown were studied. Moreover, we prepared composites containing 70 vol% PZT particles by modifying the particles. Modification of PZT particles caused a decrease in both d 33 and g 33 constants of the PZT/PU composites. [ABSTRACT FROM AUTHOR]

Abstract: Accumulative roll-bonding process is a severe plastic deformation process capable of developing grains below 1μm in diameter. In this study, microstructure, mechanical properties and electrical conductivity of commercial pure copper strips processed by accumulative roll-bonding were investigated. Transmission electron microscopic micrographs of the strips produced by eight cycles of accumulative roll-bonding process showed ultra-fine grains ∼180nm in size with high angle grain boundaries. Also tensile strength and microhardness of the accumulative roll-bonding processed samples increased with increasing the number of accumulative roll-bonding cycles. Whereas, the elongation dropped abruptly at the first cycles, above which it increased slightly. The electrical conductivity decreased with increasing accumulative roll-bonding cycles up to 6 cycles and then increased up to 8 cycles of accumulative roll-bonding process. [Copyright &y& Elsevier]