Thermophysical Properties of Five Binary Copper–Nickel Alloys

Abstract

Thermophysical properties (e.g., specific enthalpy, heat of fusion, electrical resistivity, thermal volume expansion) are measured in the liquid phase up to very high temperatures by an extreme fast pulse-heating method. Heating rates of about 10 8 K · s −1 are applied by self-heating of wire-shaped metallic specimens with a current of approximately 10,000 A. Pure elements seem to be still close to thermal equilibrium as the obtained results are in good agreement with those obtained by static methods. However, this situation might be different for alloys. The rapid volume heating can shift diffusion-controlled phase transitions at heating to higher temperatures or even make them not noticeable anymore. The simple binary Cu-Ni system was chosen to test the heating rate dependence; this system is well known and shows complete miscibility in the liquid and solid ranges of interest. This study is a further step to test the performance of the fast pulse-heating method being applied to simple and more complex alloys. Measured results of enthalpy, heat of fusion, heat capacity, and electrical resistivity in the vicinity of the melting range are presented. The results of enthalpy and heat capacity agree with simple mixing rules. The measured electrical resistivity of different compositions is compared to results obtained by electromagnetic levitation measurements.

Study on the thermal load of the laser impulse metal bonding process to the metallized thermal sensitive substrate

“…A molar enthalpy of fusion of 13 kJ mol −1 is used for the calculations. The heat capacity for the liquid phase is approximated to 636 J kg −1 K −1 according to [16].…”

Study of the effect of growth kinetic and nucleation law on grain structure simulation during gas tungsten arc welding of Cu-Ni plate

“…For Cu30Ni, the solidus is around 1200 • C and the liquidus is around 1250 • C. Thermo-physical properties were found in [17]. It was assumed in the previous section that the material properties only depend on the solid fraction that depends on partition coefficient k (see Eq.…”

“…where C ps is the solid specific heat, L the latent heat, C pl the liquid specific heat, T s the solidus temperature and T l the liquidus temperature, f l = 1 − f s is the liquid fraction, Thermo-physical parameters are taken from [17] ρ s is the specific mass of the solid phase, ρ l the specific mass of the liquid phase, ρ 0 and h 0 are respectively the specific mass and the enthalpy at ambient temperature (T 0 ).…”