Effect of Growth Velocity on Solute Distribution and Electrical Conductivity in a Directionally Solidified Cu–8 %Ag Alloy

Abstract A Cu–8 %Ag alloy was directionally solidified at different growth velocities to investigate the relationship between the solute distribution and the electrical conductivity of the material. The temperature gradient was fixed at 6.1 K/mm, and the growth rate was varied from 1 µ m/s to 200 µ m/s The planar interface was not observed in this experimental range, although cellular and dendritic interface morphologies were observed. As the growth velocity was increased, the initial silver content decreased, while the silver content near the dendrite boundary increased. The lattice parameter of the Cu – Ag alloy increased with increases in the number of silver sites in the copper lattice as measured via a calculation using the VASP (Vienna Ab-initio Package Simulation) code. The lattice parameter also decreased with increases in the growth velocity due to the decrease in silver content in the matrix. Higher electrical conductivity was obtained with higher growth velocities.