The effect of composition on microhardness and determination of electrical and thermal properties in the Sn-Cu alloys

Tin-copper of (99.99%) high purity alloys were directionally solidified upward with different compositions, C o , Sn-(1.2, 3, 6 and 15)wt% Cu under two different solidification conditions (temperature gradient ( G ) = 8 K/mm, growth rate ( V) = 7 μm/s and G = 4 K/mm, V = 130 μm/s) using a Bridgman type directional solidification apparatus. The measurements of microhardness of directionally solidified samples were obtained by using a microhardness test device. The dependence of microhardness HV (Vickers Hardness) on composition was analyzed. According to these results, it has been found that the values of HV increase with the increasing Cu content ( C o ). Variation of electrical resistivity ( ρ ) and electrical conductivity ( σ ) with the temperature were also measured by using a standard d.c. four-point probe technique. The enthalpy of fusion ( ∆H ) and specific heat ( Cp ) of the Sn-Cu alloys were determined from heating curve during the transformation from solid to liquid phase by using differential scanning calorimeter (DSC).