Influence of Cu as an impurity in Al/Ti and Al/W thin-film reactions

Thin-film reactions of Al/Ti and Al/W with 3 at. % Cu in Al were investigated by glancing-angle x-ray diffraction and Rutherford backscattering for vacuum annealing in the temperature range 300–500 °C. In the Al/Ti system, the intermetallic phase Al3Ti grows as (time)1/2. The presence of Cu in Al retards the growth rate by an order of magnitude at 400 °C and increases the activation energy from 1.8±0.1 to 2.4±0.1 eV. In the Al/W system, the presence of Cu retards the penetration of W into Al.