In the present study, surfaces of copper substrates were modified with aluminum plasma using cathodic vacuum arc (CVA) physical vapor deposition based technique. Surface treatments were carried out as a function of bias voltage for various time intervals. The effect of long and short durations of ion bombardment on the resulting microstructural features of the treated surfaces were studied and discussed It was observed that surface alloying and diffusion processes were enhanced by the application of the ion bombardment and thick (10-15 mu m) modified zones were achieved in a relatively short processing time (15-20 min). In the experiment executed with long bombardment duration, the modified zone consisted of a mixture of martensitic beta(1)-AlCu3 phase and (Cu) solid solution, accompanied with a minor amount of gamma(1)-Al4Cu9 intermetallic phase, whereas, in the experiment involving short total bombardment duration, the modified surface predominantly consisted gamma(1)-Al4Cu9 intermetallic phase, accompanied with martensitic beta(1)-AlCu3 phase at the copper aluminum interface. (C) 2010 Elsevier B.V. All rights reserved.