Akademik Veri Yönetim Sistemi
International Journal of Minerals, Metallurgy and Materials, cilt.18, sa.6, ss.659-664, 2011 (SCI-Expanded)
Zn-5wt% Al eutectic alloy was directionally solidified with different growth rates (5.32-250.0 μm/s) at a constant temperature gradient of 8.50 K/mm using a Bridgman-type growth apparatus. The values of eutectic spacing were measured from transverse sections of the samples. The dependences of the eutectic spacing and undercooling on growth rate are determined as λ=9.21V -0.53 and ΔT=0.0245V 0.53 , respectively. The results obtained in this work were compared with the Jackson-Hunt eutectic theory and the similar experimental results in the literature. Microhardness of directionally solidified samples was also measured by using a microhardness test device. The dependency of the microhardness on growth rate is found as Hv=115.64V 0.13 . Afterwards, the electrical resistivity (r) of the casting alloy changes from 40×10 -9 to 108×10 -9 Ω•m with the temperature rising in the range of 300-630 K. The enthalpy of fusion (ΔH) and specific heat (C p ) for the Zn-Al eutectic alloy are calculated to be 113.37 J/g and 0.309 J/(g•K), respectively by means of differential scanning calorimetry (DSC) from heating trace during the transformation from liquid to solid. © 2011 University of Science and Technology Beijing and Springer-Verlag Berlin Heidelberg.