Residual stress in deuterium implanted nominal copper coatings

The effects of deuterium (D) implantation on the residual stresses in Cu an d CuAl2 phases present in nominal Cu coatings (containing Al) deposited on Al-alloy (Al-6061) substrates were measured using an x-ray diffraction tech nique. The coatings were deposited by radio frequency magnetron sputtering of a pure Cu target under identical conditions and Al was incorporated in t he coatings during growth by diffusion from the substrate. Deuterium was im planted in the coatings at energies of 40 or 40+120 keV with fluences of 1 x 10(21), 2 x 10(21), or 3 x 10(21) D+/m(2). Pole figures of the Cu phase i n the coatings prior to and after implantation indicated no effect of impla ntation on the fibrous texture. Triaxial stress analysis indicated the surf ace normal stress component to be negligible in Cu and slightly tensile in CuAl2 under all conditions. Furthermore, under all conditions, the in-plane residual stresses in both phases were found to be compressive and nearly i sotropic. The magnitude of the isotropic compressive stress was always high er in CuAl2 as compared to Cu. The compressive residual stresses in the Cu phase changed only mildly with increasing coating weight, ion energy, and f luence. However, in the CuAl2 phase the compressive residual stresses chang ed markedly with increasing ion energy (initial decrease followed by leveli ng off) and increasing ion fluence (initial decrease followed by an increas e), but remained unaffected by increasing coating weight. (C) 2000 American Institute of Physics. [S0021-8979(00)07819-1].