Growth kinetics of intermetallic compounds in Cu–Ti diffusion couples

Abstract

Cu–Ti diffusion couples have been designed in the temperature range from 1013 K to 1163 K. Ensuing intermetallic compounds, including Cu4Ti, Cu4Ti3, CuTi, and the elusive CuTi2, have been identified in the diffusion zone. Growth kinetics and interdiffusion coefficients of involved Cu–Ti intermetallics have been quantified based on the measured compositional profiles using electro-probe microanalyzer. Moreover, activation energies required for the growth of these intermetallics have been confirmed to be 85.9 kJ mol−1 atom (Cu4Ti), 101.0 kJ mol−1 atom (Cu4Ti3), 70.0 kJ mol−1 atom (CuTi), and 64.9 kJ mol−1 atom (CuTi2), respectively. Our current findings could enable a rational design towards fully utilizing encrypted phases which are otherwise difficult to obtain.